JPH0660306A - Rotation scanning type magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To provide functions including a partial rewriting needed at a broadcasting station, etc., without increasing LED train for controlling a drum mounted circuit. CONSTITUTION:An RF detector constituted of a detector amplifier 22, a peak detector 23 and a comparator 24 for detecting a recording RF signal is provided in a recording circuit connected to plural recording heads. Then, only during the period when the recording RF signal is detected, the amplifier 27 of an output stage is made to an active state via an and gate 25 and an output off circuit 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary scanning type magnetic recording / reproducing apparatus such as a VTR, and more particularly to a control apparatus for a recording / reproducing circuit mounted on a rotating drum.

[0002]

2. Description of the Related Art Wide band, high transmission rate VTRs (hereinafter, collectively referred to as wide band / high transmission rate VTRs) such as high definition VTRs for HDTVs and digital VTRs of current television systems have been developed. It has been put to practical use. In order to realize a wide band and a high transmission rate, these VTRs have been devised as follows.

(1) Broad band between the magnetic head and the recording circuit, the wide band of the recording system by directly connecting both without a rotary transformer interfering with a high transmission rate being interposed,
Aim to increase the transmission rate.

(2) The resonance frequency between the magnetic head and the preamplifier is increased to achieve a wide band and a high transmission rate of the reproducing system, so that a good signal-to-noise ratio of the reproduced signal can be obtained on the rotating drum. A reproducing circuit is mounted in the vicinity of the magnetic head, and a minute reproducing signal from the magnetic head mounted on the rotating drum is increased in level and then transmitted to the outside of the rotating drum. This is also effective in reducing external noise.

(3) A rotary transformer for transmitting signals between the inside and outside of the rotary drum, a driver circuit for driving the rotary transformer, and a receiver circuit for receiving signals from the rotary transformer are provided for reducing external noise and widening the band. The scanner is mounted inside a scanner (a generic name for drum mechanicals including rotary drums and fixed drums) in proximity to a rotary transformer.

By the way, in this kind of wide band / high transmission rate VTR, as disclosed in VR87-5 of the Institute of Television Engineers of Japan, at least six magnetic heads are used in addition to those for normal reproduction and special reproduction. Must. For example, D-1 format 525 digital VT
Taking R as an example, 16 magnetic heads are used.
In the case of a digital VTR for HDTV, a total of 18 magnetic heads, 8 for recording and 8 for reproducing, and 2 for flying erase are used. A rotary transformer is usually used for signal transmission inside and outside the rotating drum. The number of channels of the rotary transformer is the same as the number of magnetic heads mounted on the rotary drum.

However, the rotary transformer having the number of channels corresponding to a large number of magnetic heads is mounted on the scanner, and the number of recording circuits and reproducing circuits equal to the number of magnetic heads are mounted on the rotary drum, and the number of channels of the rotary transformer is further increased. If the same number of rotary transformer driver circuits and rotary transformer receiver circuits are mounted in the scanner, the scanner mechanism becomes large and complicated. On the other hand, the rotary transformer is required to have a wide band and low crosstalk between channels, and there is a limit to miniaturization.

[0008] Therefore, the inventors of the present invention, Japanese Patent Application No. 11-12790.
6 and Japanese Patent Application No. 1-127911, a method for reducing the size of the scanner mechanism by reducing the number of rotary transformer driver circuits and rotary transformer receiver circuits and the number of rotary transformer channels was proposed. According to this method, n recording circuits or reproducing circuits or n recording / reproducing circuits are commonly connected to the same transmission channel of the rotary transformer, and these are sequentially and selectively switched to an active / inactive state, whereby It becomes possible to make the number of channels 1 / n of the number of the magnetic head and the recording circuit or the reproducing circuit or the recording / reproducing circuit. Furthermore, the number of driver circuits and receiver circuits of the rotary transformer can be reduced to 1 / n.

For example, when the recording head and the recording circuit are eight, the reproducing head and the reproducing circuit are eight, and the effective recording area angle on the tape is 180 °, two recording circuits and two reproducing circuits are provided for each rotary transformer. If it is connected to the transmission channel of the above, the transmission channel of the rotary transformer may be four channels for each of the recording system and the reproducing system. As a result, the mechanism of the scanner is simplified, the reliability is improved, and at the same time, the system is small and lightweight, and the cost can be reduced. Hereinafter, this known technique will be described.

In the rotary transformer proposed in Japanese Patent Application No. 1-127906, for example, a reproducing system will be described. Two windings are inserted in one winding groove of the rotary side element of the rotary transformer, and these windings are A structure in which reproduction circuits connected to two reproduction heads facing each other by 180 ° are connected, and one circuit winding is inserted in one winding groove of the other fixed drum side element and received by a rotary transformer receiver. Has become. That is, the two regeneration circuits are connected to the same transmission channel of the rotary transformer. With this method, it is not necessary to lengthen the connection wiring between the regenerative circuits in the rotary drum and the rotary transformer, and by pulling out the windings of the rotary transformer at positions close to each of the regenerative circuits facing each other by 180 °, reproduction is performed. The feature is that the connection wiring between the circuit and the rotary transformer becomes simple.

The system described in Japanese Patent Application No. 1-127911 arranges a plurality of LEDs on the fixed side of the scanner and
A photodetector is provided with a rotary drum-mounted circuit in which the same number of photodetectors as heads are arranged at positions on the rotary drum side that can be opposed to this, and the same transmission channel of the rotary transformer is shared by n recording circuits or reproducing circuits or recording / reproducing circuits. This is a system in which the number of channels of the rotary transformer is reduced by sequentially switching to the active / inactive state every 180 ° rotation of the rotary drum by the output. The following is a method of switching the active / inactive state of such a circuit mounted on the rotating drum.
It is called the 80 ° switching method. This 180 ° switching system simplifies the scanner mechanism, improves reliability, and makes it possible to reduce the size and weight and reduce the cost.

Referring to FIGS. 90 (a) and 90 (b), this 18
The outline of the 0 ° switching method will be described. 90A is a sectional view of the scanner unit, and FIG. 90B is a schematic plan view. 1 is a scanner (generic term for a rotary drum and a fixed drum), 2
Is a magnetic tape, 3 is a rotating drum, and 4 is a fixed drum. In this example, photodetectors 5a, 5 for controlling a recording circuit and a reproducing circuit (not shown) on the rotating drum 3 side.
b and 6a and 6b are located inside the recording heads R1 and R2 and the reproduction P1 and P2, respectively, and mounted corresponding to each head. On the fixed drum 4 side, when the effective recording area angle (corresponding to the winding angle) on the tape is 180 °,
A plurality of recording LEDs and reproducing LEDs are arranged in a semi-arc shape over the effective recording area at positions where they can face the photodetector. Hereinafter, the plurality of LEDs for recording and reproducing will be referred to as an LED row.

The recording circuit is controlled according to the recording LED string 7, the reproducing circuit is controlled according to the reproducing LED string 8, and the recording LED string 7 and the reproducing LED string 8 are controlled by the recording / reproducing control circuit 9. To do. The photodetectors 5a, 5b and 6a, 6b on the rotating drum side receive control light from the recording LED array 7 and the reproducing LED array 8 and control the active / inactive state of the recording circuit and the reproducing circuit, for example, the recording circuit. Also, it is performed by turning on / off the power input of the reproducing circuit.

That is, since the rotary drum 3 is rotating in the direction of the arrow, the recording circuit connected to the head R1 is controlled by the output of the photodetector 5a, and the head R
1 is in the active state while passing through the recording area with the recording LED row 7, and is inactive while the head R1 is passing through the area without the recording LED row 7. Similarly, the recording circuit connected to the head R2 is the photodetector 5b.
Controlled by the output of. The reproducing circuit connected to the head P1 is controlled by the output of the photodetector 6a and is in an active state while the head P1 is passing through the recording area having the reproducing LED row 8, and the head P1 does not have the reproducing LED row 8. It becomes inactive while passing through. Similarly, the reproducing circuit of the head P2 is controlled by the output of the photo detector 6b.

In a recent digital VTR, an audio signal is converted into a PCM and recorded on an audio track on the same line as a video track.
CM audio signals are frequently rewritten. Video signals are also less frequent than audio signals, but require partial rewriting. Therefore, this kind of digital VTR
It can be said that the partial rewriting function is indispensable as a function of. However, the normal playback in the above 180 ° switching method,
In addition to the function of normal recording, only the audio track,
In order to perform partial rewriting of only the video track, in addition to the normal recording and normal playback LED rows, the array track diameters of the audio track partial rewrite recording LED row and the video partial rewrite recording LED row are usually set. Arrange the LED array for recording and normal reproduction differently, or set the LED array for normal recording to L for audio only and video only.
It is necessary to take measures such as dividing into ED columns.

FIG. 91 shows the footprint of the D2 format VTR, and FIG. 92 shows the case where the drum mounted circuit control LED row corresponding to the format is divided into the normal recording LED row for audio and video. Note that the footprint of the D-2 format VTR shown in FIG. 92 is described in Technical Description of Television Engineers (Special Issue on Rules), No. 15, P. Quoted from 46. In FIG. 92, the LED array that controls the rotary drum mounting circuit is attached to the fixed drum 4. The recording circuit (not shown) is controlled by the recording LED strings 7a to 7e, and the reproducing circuit (not shown) is controlled by the reproducing LED string 8. During normal recording, all the recording LED rows 7a to 7e are made to emit light.
If you want to rewrite only the audio track,
LE for audio tracks in D2 format
The D columns 7a, 7b, 7d, 7e are made to emit light. Further, when partial rewriting of the recording track for only video is performed, only the recording LED row 7c is caused to emit light. These recording L
The ED columns 7a to 7e and the reproducing LED column 8 are controlled by the LED column control circuit 10.

As shown in this example, in order to partially rewrite only the audio track and the video track, the recording LED strings 7a to 7e are replaced with audio recording LED strings 7a, 7b, 7d and 7e. For recording L
Since it is necessary to divide the ED column 7c, the control thereof becomes complicated, and the configuration of the LED column control circuit 10 becomes complicated accordingly. Also, four audio channels are usually required, and of course partial rewriting is required for each channel. In that case, the audio area of the recording LED array has to be increased by the number of channels, and its control becomes more complicated. Further, depending on the system configuration, it may be necessary to add an erasing function. In that case, an erasing LED array is required, which makes control more and more complicated. Furthermore, not only is it difficult to fabricate the recording LED strings 7a, 7b, 7d, 7e corresponding to the audio tracks divided into relatively short lengths, but also in the gap portion between the audio channels or between the audio channels and the video channels. , It is difficult to prevent the light for recording control from leaking to the channel adjacent to the partially rewritten channel.

On the other hand, regarding reproduction, a signal for controlling the reproduction LED row 8, that is, a signal for generating a 180 ° switching signal must be supplied from the outside of the rotary drum. Usually, in consideration of the function of the VTR, the reproducing circuit is normally activated during simultaneous recording and inactive during simultaneous reproduction. In this case, 18
The reproduction circuit may be switched every 0 ° and the reproduction signal may be transmitted to the outside of the rotary drum by the rotary transformer. Still playback,
Even during special playback such as slow playback, fast forward playback, and fast reverse playback, the playback signal may be partially lost or the playback output may drop, but the control to switch the playback circuit every 180 ° does not change at all. . Therefore, it is desirable that the 180 ° switching signal can be generated inside the rotating drum without transmitting the control signal from the outside.

Further, in the 180 ° switching system as described above, the recording and reproducing LEDs are provided on the fixed side of the scanner.
Rows are required, and in some cases also LED rows for erasing. Further, as many photodetectors as the number of magnetic heads are required on the rotary drum side. As described above, the number of magnetic heads in the wide band / high transmission rate VTR is extremely large, and the photodetector and its accompanying components are further increased. Therefore, the manufacturing cost is increased, the size of the scanner is increased, and the size of the entire VTR device is increased. May be invited. Further, each photodetector is located on a straight line connecting the head gap of the magnetic head connected to the recording circuit and the reproduction circuit controlled by itself and the rotation center of the rotating drum, and the distance from the rotation center of the rotating drum is It must be precisely aligned with each other to be equal to the LED array on the fixed drum to be controlled. For this reason,
The assembly of the scanner becomes complicated, which is disadvantageous in terms of maintenance of the circuit mounted on the rotating drum and manufacturing cost.

On the other hand, a method of transmitting a control signal for 180 ° switching to the rotary drum by utilizing a slip ring, a rotary drum, or optical transmission is also conceivable. However, the method of transmitting the control signal by the slip ring has a complicated structure because the number of channels of the slip ring also increases when the number of channels of the magnetic head increases, and the slip ring has a short life and a lot of sliding noise. , Lacks reliability of signal transmission. The method of transmitting the control signal by the rotary transformer is
When the number of channels of the magnetic head is increased, the control signal of the recording / reproducing circuit corresponding to the multi-channel magnetic head is transmitted by the rotary drum of one channel, and the peripheral circuit becomes very complicated. With the method using optical transmission, since it is difficult to transmit signals with multiple beams, one optical beam from the center of rotation transmits the control signals of the recording / reproducing circuit corresponding to the multi-channel magnetic head. The circuit becomes very complicated.

[0021]

As described above, the conventional drum-mounted circuit control system has a problem that it is very difficult to partially rewrite a recording track because the number of LED rows controlling the drum-mounted circuit increases. Further, regarding reproduction, there is a problem in that a signal for controlling the reproduction LED must be supplied from outside the rotary drum. Furthermore, as a common matter for controlling the recording / reproducing and erasing circuits, a large number of LED arrays and photodetectors corresponding to the number of magnetic heads are required, resulting in an increase in manufacturing cost, an increase in size of the scanner, an increase in size of the entire VTR device, There are problems such as complicated assembly of the scanner, maintenance of the circuit mounted on the rotating drum, and a method of transmitting a control signal for 180 ° switching to the rotating drum by using a slip ring, a rotating drum, or optical transmission. There were major problems in terms of reliability of transmission and complication of peripheral circuits.

The present invention has been made in view of the above problems. A first object of the present invention is to control a drum mounting circuit.
It is an object of the present invention to provide a rotary scanning type magnetic recording / reproducing apparatus that can have a function including partial rewriting required in a broadcasting station without increasing the number of ED rows or using an LED row.

A second object of the present invention is a rotary scanning type which can generate a signal for controlling a reproducing circuit inside a rotary drum without using an LED array for controlling a drum mounting circuit. It is to provide a magnetic recording / reproducing apparatus.

Further, a third object of the present invention is to control a drum mounting circuit such as a recording circuit, a reproducing circuit and an erasing circuit inside the rotary drum without using an LED array for controlling the drum mounting circuit. It is an object of the present invention to provide a rotary scanning type magnetic recording / reproducing apparatus capable of generating a signal.

[0025]

In order to achieve the first object of the present invention, a plurality of recording heads are provided with first detecting means for detecting a period in which each recording head is in contact with a magnetic tape. Second detecting means for detecting an information signal to be recorded transmitted from the outside of the rotary drum to the recording circuit in the recording circuit connected to each recording head, and the recording circuit by the first detecting means. It is detected that the recording head corresponding to is contacting the magnetic tape, and the second
The control means for activating the output stage of the recording circuit is provided only during the period when the information signal is detected by the detection means.

The first detecting means is specifically provided on, for example, a surface of a fixed drum which is arranged so as to face the rotary drum and which faces the rotary drum, and has a predetermined angle range along the rotation direction of the rotary drum. A plurality of rows of light-emitting elements arranged in an annular shape over a plurality of rows, and a plurality of light-receiving elements provided at a position corresponding to each of the recording heads on a surface of the rotating drum facing the fixed drum, The light receiving element outputs a signal indicating the period during which each of the recording heads is in contact with the magnetic tape.

Further, in order to achieve the first object of the present invention, an information signal to be recorded, which is transmitted from the outside of the rotary drum to the recording circuits, is provided in a plurality of recording circuits according to the rotational position of the rotary drum. First detecting means for detecting an amplitude modulation signal which is added and amplitude-modulated to have an amplitude different from that of the information signal; and first detecting means for detecting an information signal to be recorded which is transmitted to the recording circuit from outside the rotary drum. Control for setting the output stage of the recording circuit to the active state only during the period in which the amplitude modulation signal having a predetermined amplitude is detected by the second detecting means and the information signal is detected by the second detecting means. Means are provided.

Further, in order to achieve the first object of the present invention, a recording circuit designating code added to an information signal to be recorded transmitted from the outside of the rotary drum to the recording circuits in a plurality of recording circuits. And a control means for activating the output stage of the recording circuit for a period in which the recording circuit specifying code detected by the detecting circuit matches the unique code defined in the recording circuit. It is characterized by

Further, in order to achieve the first object of the present invention, the sync block number or the sync block number in the sync block added to the information signal to be recorded transmitted from the outside of the rotary drum in the plurality of recording circuits. Detecting means for detecting a code representing at least one of the track number, the segment number and the field number in the sector ID, and the code detected by this detecting means coincides with the unique code defined in each recording circuit. The recording circuit is configured so that at least the output stage of the recording circuit is in an active state for a predetermined period.

In order to achieve the second object of the present invention, a reproducing circuit connected to each of a plurality of reproducing heads is provided in the rotary drum, and the reproducing circuit detects the information signal reproduced by the reproducing head. It is characterized in that a control means for activating only the reproducing circuit is provided.

In order to achieve the third object of the present invention, it is determined whether or not the magnetic tape and the magnetic head are in contact with each other in the vicinity of each of the plurality of magnetic heads for recording, reproducing and erasing the information signal. At least one of a recording circuit, a reproducing circuit, and an erasing circuit among a plurality of drum-mounted circuits including a recording circuit, a reproducing circuit, and an erasing circuit which are respectively connected to the magnetic head and which are provided with a tape-head contact detecting means for detecting In addition, the control for activating at least the output stage of at least one of the recording circuit, the reproducing circuit and the erasing circuit only during the period when the tape-head contact detecting means detects that the magnetic tape and the magnetic head are in contact with each other. Means are provided.

[0032]

By adding the control means for controlling the active / inactive state of the output stage of the recording circuit to the recording circuit in this way, the control of the drum mounting circuit becomes very simple. For example, in the system using the light emitting element array and the light receiving element as the first detecting means, only the recording light emitting element array is prepared as the light emitting element array for controlling the drum mounting circuit, and the normal recording, the video track only, and the audio are recorded. It becomes possible to rewrite only the tracks. In addition, since the number of elements in the light emitting element array is reduced, power consumption can be reduced and cost can be reduced.

Further, the first detecting means detects the amplitude modulation signal added to the information signal and the second detecting means detects the information signal, the recording circuit designating code, the sync block number or the sector ID. In the method of detecting the code representing at least one of the track number, the segment number and the field number,
Normal recording and partial rewriting of only the video track and audio track are possible without using the light emitting element array at all, and 180 ° switching by LED array, photo detector, slip ring, rotating drum, or optical transmission is possible. Since the transmission of a control signal for that is unnecessary, reliability is improved and peripheral circuits are not complicated.

On the other hand, if a circuit for making the output stage of the reproducing circuit active / inactive is added to the reproducing circuit, the control of the drum-mounted circuit becomes very simple, and the light emitting element array becomes unnecessary, resulting in low power consumption. Electricity conversion and cost reduction can be achieved.

Further, the tape-head contact detecting means provided in at least one of the recording circuit, the reproducing circuit and the erasing circuit of the drum mounting circuit detects that the magnetic tape and the magnetic head are in contact with each other. By making at least the output stage of the circuit active for a certain period, it is possible to control 180 ° switching and the like only by the control signal generated inside the rotating drum without using the light emitting element array. The control circuit becomes simple. This facilitates the assembly of the scanner and the maintenance of the drum-mounted circuit, thus reducing the cost, downsizing the scanner, and downsizing the entire VTR device.

[0036]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment 180 of the present invention.
2A and 2B are diagrams schematically showing a configuration of a scanner unit incorporating a switching type rotary drum-mounted circuit control device, in which FIG. 7A is a plan view showing a position of a head, FIG. 9B is a sectional view, and FIG. It is a top view which shows arrangement | positioning of the LED row.
In this embodiment, the effective recording area angle of the magnetic tape 2 is set to 1
A case where normal recording / reproduction is performed at 80 ° will be described. Since the erasing circuit is exactly the same as the recording circuit, it is omitted for simplification of description.

In the scanner 1, the magnetic tape 2 has an effective recording area of information signals of 180 on the peripheral surface of the rotating drum 3.
It is wound so that it becomes °. That is, the winding angle of the tape 2 on the rotary drum is 180 °. A fixed drum 4 is provided coaxially with the rotary drum 3 so as to face the rotary drum 3. A magnetic head is provided on the rotary drum 3 as a recording head 11 (R) as shown in FIG.
1, R2) and the reproducing head 12 (P1, P2) are provided to face each other by 180 °.

Further, in this embodiment, the recording heads R1 and R2 and the reproducing heads P1 and P2 are provided on the rotary drum 3 side.
Of the recording photodetectors 5 (5) located on the inner side of each of the heads and on the same straight line in the radial direction as these heads.
a, 5b) and a reproduction photodetector 6 (6a, 6a)
b) is installed. On the other hand, on the fixed drum 4 side, the recording LED row 7 and the reproducing LED row 8 are effectively arranged along the rotation direction of the rotating drum 3 at positions where they can face the photodetectors 5 and 6 as the rotating drum 3 rotates. They are arranged in a semi-annular shape over the recording area, in this case an angular range of 180 °. Each of the LED rows 7 and 8 has a plurality of LEDs arranged in a semi-annular shape.

The rotary drum 3 has recording circuits 13a, 13
b and the reproducing circuits 14a and 14b are mounted, and the switching control of the active / inactive state of the recording circuits 13a and 13b is performed by the recording LED array 7, and the switching control of the active / control active state of the reproducing circuits 14a and 14b is for the reproduction. This is performed by the LED row 8 or according to the carrier detection result described later. Furthermore, the control of the recording LED row 7 and the reproduction LED row 8 is
This is performed by the recording / reproduction control circuit 9.

The recording circuits 13a and 13b have their inputs connected to a common rotary side element of a rotary transformer, amplify an information signal input from the outside of the rotary drum, and record heads R1 and R2 arranged opposite to each other by 180 °. Drive each.

The information signal recorded on the magnetic tape 2 is
After being reproduced by the reproducing heads P1 and P2 provided opposite to each other by 180 ° and amplified by the reproducing circuits 14a and 14b, the output thereof is transmitted to the outside of the rotating drum by the rotating transformer connected to the common rotating side element. To be done.

FIG. 2 is a circuit diagram showing a more specific structure in the scanner 1 of FIG. The information signal to be recorded on the magnetic tape (hereinafter referred to as a recording RF signal) is amplified by the rotary transformer drive circuit 15 and is then rotated by the rotary transformer 17a.
Is transmitted to the inside of the rotary drum via. The recording RF signal input to the rotary transformer drive circuit 15 includes both information signals recorded by the recording heads R1 and R2.

As the rotary transformers 17a and 17b, the rotary transformers proposed in Japanese Patent Application No. 1-127906 described above are used. That is, in the recording system, one circuit winding is inserted in one winding groove of the fixed side element of the rotary transformer 17a, the recording RF signal is amplified by the rotary transformer drive circuit 15, and the rotary drum is passed through the rotary transformer 17a. Transmit to the inside. Two windings are inserted in one winding groove in the rotary side element of the rotary transformer 17a, and these windings are connected to the recording circuits 13a and 13b, respectively, and the recording RF signals are received by the recording circuits 13a and 13b.

In the reproducing system, two windings are inserted in one winding groove of the rotary side element of the rotary transformer 17b, and these windings are connected to the reproducing circuits 14a and 14b, respectively, and the fixed side element of the rotary transformer 17b is connected. One winding is inserted in one winding groove of the above so that the rotary transformer receiver circuit 16 receives the information signal (hereinafter referred to as a reproduction RF signal) reproduced by the reproduction heads P1 and P2.

FIG. 3 shows a series of time sequences of the switching operation of the recording / reproducing circuit. Recording circuits 13a and 13b
3 are sequentially switched to the active state / inactive state at every 180 ° by the R1 switching signal of FIG. 3 (a) and the R2 switching signal of FIG. 3 (b), and the R of FIG. 3 (c) is input.
The F signal is supplied to the recording head R1 or R2 in the active state, and the RF signal corresponding to the recording current shown in FIGS. 3D and 3E is recorded on the magnetic tape.

On the other hand, the RF signals reproduced from the magnetic tape by the reproducing heads P1 and P2 are reproduced by the reproducing circuits 14a and 14a.
It is amplified by b and transmitted to the outside of the rotary drum through the rotary transformer 17b.

The reproducing circuits 14a and 14b are set to 1 by the P1 switching signal shown in FIG. 3 (f) and the P2 switching signal shown in (g).
The active / inactive state is sequentially switched at intervals of 80 °, and the P1 reproduction signal of (h) and the P2 of (i) reproduced from the reproduction head P1 or P2 in the active state.
From the reproduction signal, the reproduction RF signal of (j) is converted to the rotary transformer 1
It is transmitted from 7b to the outside of the rotary drum. Rotating transformer 17b
The reproduction RF signal transmitted from the receiver is received by the rotary trans-receive circuit 16 and transmitted to the subsequent circuit. The reproduction RF signal output from the rotary trans-receive circuit 16 by this switching operation includes both the RF signals reproduced by the reproduction heads P1 and P2.

A method for simplifying the control of the circuit mounted on the rotary drum and a circuit method for reducing the number of channels of the rotary transformer in this embodiment will be described.

The reproducing circuits 14a and 14b use the rotary transformer proposed in Japanese Patent Application No. 1-127906 of the prior application, so that the reproducing circuits in the inactive state are prevented from deteriorating in frequency characteristics. In this case, keep the output in the high impedance state. FIG. 4 shows a specific example of such a reproducing circuit. Although the output of this reproducing circuit is a balanced output, only one side thereof is shown for the sake of simplicity.

Usually, in this type of reproducing circuit, an emitter follower or a Darlington emitter follower is used in the output stage in order to have a sufficient driving capability for a load. In FIG. 4, the emitter follower Q1 is used.
Transistor Q2, diode D1 and resistors Z1, Z
2 constitutes a constant current circuit, and this constant current circuit supplies a constant current to the emitter follower Q1. Switching of the active / inactive state of the emitter follower Q1 is performed by the transistors Q3 and Q4 and the inverter IN1. When the switching signal is at H (high) level, the transistor Q
The base of 3, Q4 becomes L (low) level and Q3, Q4
Turns off, the emitter follower Q1 operates, and the playback R
Output F signal. When the switching signal is L level, Q
The bases of 3 and Q4 are at the H level, Q3 and Q4 are turned on, the base of the emitter follower Q1 is at the L level, the emitter follower Q1 is turned off, and its output is in the high impedance state.

Next, the recording circuits 13a and 13b will be described. The recording circuits 13a and 13b have a function of detecting the presence or absence of a recording RF signal, that is, a carrier detection function.
FIG. 5 is a diagram showing a specific example of a recording circuit having such a carrier detecting function. Although the recording circuit 13a is shown here, the recording circuit 13b has the same configuration.

In FIG. 5, the recording RF signal transmitted from the rotary transformer (not shown) is the recording circuit 13.
It is input to the input 1 and the input 2 of a. Recorded RF input
The signal is branched into two, one of which is input to the emitter follower 21 for current amplification of the recording RF signal, and the other of which is input to the detector amplifier 22. The detector amplifier 22 has a recording R
The F signal is amplified so as to have a predetermined signal amplitude and sent to the peak detector 23 at the next stage. The peak detector 23 detects the peak of the input recording RF signal and outputs a detection signal voltage corresponding to the peak value. The detection signal voltage output from the peak detector 23 is stored in the comparator 24.
Entered in. When the input detection signal voltage exceeds a predetermined threshold value, the comparator 24 outputs an H (high) level signal to the AND gate 25 at the next stage.

As described above, when the recording RF signal having a predetermined amplitude level or more is input, the recording circuit 13a uses the RF detector composed of the detector amplifier 22, the peak detector 23 and the comparator 24 to set the AND gate 25 at the H level. The signal of is output. On the contrary, when a recording RF signal having a predetermined amplitude level or less is input, the RF detector outputs an L level signal to the AND gate 25.
The other input of the AND gate 25 is a recording circuit enable input, and a 180 ° switching signal (R1 switching signal) as shown in FIG. 3 is input from the photodetector 5a of FIG. 1 through a not-shown detector amplifier and binarization circuit. To be done.

The output of the AND gate 25 is supplied as a control signal to the amplifier 27 via the output off circuit 26.
The amplifier 27 further amplifies the recording RF signal current-amplified by the emitter follower 21 and outputs the amplified recording RF signal to the output 1 and the output 2.

FIGS. 6 and 7 show the operation sequences of the respective circuit parts inside and outside the recording circuit 13a during normal recording and insert recording. Both the RF detector side input (X) and the recording circuit enable input (Y) of the AND gate 25 are at H level.
When the level becomes high, the output (S) of the AND gate 25 is H
It becomes a level. At this time, the output off circuit 26 activates the amplifier 27 at the output stage of the recording circuit 13a, and the amplifier 27 supplies a recording current corresponding to the recording RF signal to the magnetic head (not shown).

On the contrary, when either the RF detector side input (X) of the AND gate 25 or the recording circuit enable input (Y) becomes L level, the output (S) of the AND gate 25 becomes L level. Therefore, the amplifier 27 is turned off by the output off circuit 26, that is, the recording circuit 13a is deactivated. As a result, the recording RF signal output is stopped, and the amplifier 27 enters a state in which the recording current is not supplied to the magnetic head.

This operation is particularly effective at the time of insert recording whose operation sequence is shown in FIG. That is, since the rotary transformer is commonly used at the time of insert recording, the recording circuits 13a and 13b are connected to the respective Rs.
A recording RF signal is output by controlling ON / OFF of the amplifier 27 through the AND gate 25 and the output OFF circuit 26 by both the 1-switching signal (Y) and the RF detector output (X) signal. By doing so, as can be seen from the operation sequence example of FIG. 7, the partial rewriting can be easily performed by transmitting the recording RF signal to be inserted into the portion to be insert-recorded.

Next, an embodiment of the amplifier section of the recording circuits 13a and 13b will be described. FIG. 8 is a circuit diagram showing in detail the emitter follower 21, the output off circuit 26, and the amplifier 27 in FIG. This circuit is configured using a differential amplifier, an RF transformer with a midpoint tap, and a constant current circuit.

For the input of the recording circuit, Japanese Patent Application No. 1-127 of the prior application
In order to prevent the deterioration of the frequency characteristic due to the use of the rotary transformer proposed in 906, in FIG. 8, the emitter followers Q10 and Q11 are used in the input stage to increase the input impedance. A Darlington emitter follower may be used instead of the normal emitter follower.
Note that the bias of the input circuit is not shown in FIG. 8 for simplicity. The RF signals current-amplified by the emitter followers Q10 and Q11 are transferred to the transistors Q12 and Q13.
And a resistor Z7 for amplifying the differential amplifier. An RF recording current is supplied from the differential amplifier to the recording head R1 via the RF transformer. A transistor Q14 and a resistor Z3, a transistor Q15 and a resistor Z4 are constant current circuits connected to the emitters of the emitter followers Q10 and Q11, respectively, and a transistor Q16 and a resistor Z5, and a transistor Q17 and a resistor Z6 are connected to the emitters of the transistors Q12 and Q13. The respective constant current circuits are configured.
The resistors Z1 and Z2 and the diode D1 are a reference bias circuit for these constant current circuits.

When the switching signal is input to the base of the transistor Q18 via the inverter IN10, the transistor Q18 is turned on when the switching signal is at the L level, and the resistor Z1 ,.
The reference bias circuit composed of Z2 and the diode D1 and the base potentials of the transistors Q14 to Q17 are connected to the ground potential GND.
To prevent the recording current from flowing through the head R1.

That is, the amplifier (emitter follower and differential amplifier) in FIG. 8 is inactive when the base potential of the transistor Q18 is at H level and active when it is at L level. Since the switching signal is inverted by the inverter IN10 and then input to the base of the transistor Q18, the switching signal is eventually at the H level, the amplifier is in the active state, and the recording current corresponding to the RF signal is supplied to the head R1. On the contrary, when the switching signal is at the L level, the amplifier is in the inactive state and the recording current is not supplied to the head R1, and the operation described with reference to FIGS.

Although the RF detector is added to the recording circuit in the above embodiment, a similar RF detector may be added to the erasing circuit. In this case, by inputting the erase signal to the erase circuit at the timing of performing the erase, the erase circuit is controlled by the L signal.
It is not necessary to use the ED column, and the same effect as in the case of the recording circuit can be obtained.

Further, in FIG. 5, switching signal input and RF
Other logic gates may be used in the AND gate 25 portion depending on the output form of the detector.

By the way, the recording LED array 7 in FIG.
The reproducing LED row 8 is used as a linear light emitting element. In order to realize the linear light emission, it is necessary to arrange a plurality of LEDs densely for the effective recording area so that the light from the LED row is not cut off in the middle in the LED array direction. It is very difficult to realize linear light emission without interrupting light in the middle by using a single LED molded in view of the mounting pitch, the outer diameter dimension, the mounting accuracy, and the like. Therefore, a bare chip is used for the LED.

However, as shown in FIG. 9, the LED bare chip emits light in five directions of + X, -X, + Y, -Y, and Z, and the light emission thereof is the light intensity distribution shown in FIG. It is said to be distributed). Of the light emitted from the LED bare chip, the desired light direction is only the Z direction, so + X, -X, +
It is required that the light in the Y and -Y directions is also condensed in the Z direction so that the linear control light with less unevenness in light intensity (ripple of light quantity) can be efficiently emitted with a small driving current.

The LED generally has a shorter life as the drive current increases, in other words, the amount of light emitted increases. Therefore, in terms of the reliability of the VTR system, the LED array is required to have a long life, that is, high efficiency and low power consumption.

Further, since the LED bare chip emits light in five directions, light leaks (crosstalk) from the reproducing LED row 8 to the recording photodetectors 5a and 5b in FIG. 1 or from the recording LED row 7. Crosstalk of light to the reproduction photodetectors 6a and 6b becomes a problem. For example, when the VTR is in playback mode, the playback LED
When crosstalk of light from the row 8 to the recording photodetectors 5a and 5b occurs, the recording circuit malfunctions when the amount of crosstalk is large.

In consideration of such a situation, in the present embodiment, as shown in FIG. 1, the effective area of the fixed drum 4 is formed on the end face of the fixed drum 4 facing the rotary drum 3 along the rotation direction of the rotary drum 3. A semi-annular groove (or hole) is formed over the length, and the LED rows 7 and 8 are arranged inside the groove to form a linear light emitting element.

Hereinafter, various arrangement methods of the LED array will be described with reference to FIGS. 11 to 20, taking the recording LED array 7 as an example.

In FIG. 11, a plurality of LED bare chips constituting the LED row 7 are mounted on the LED substrate 401, and
LED board 40 connected to the recording / reproducing control circuit 9
The bonding pattern 402 is connected to the upper wiring pattern. The LED substrate 401 is arranged in a semi-circular groove 403 formed on the end surface of the fixed drum 4 facing the rotary drum 3 along the rotation direction of the rotary drum 3. With this configuration, the light diverging from the LED array 7 can be efficiently collected in the direction orthogonal to the LED arrangement direction to form a light arc of a thin light flux. Therefore, it is possible to reduce the optical crosstalk from the above-described recording LED array 7 to the reproduction photodetectors 6a and 6b.

FIG. 12 shows a plurality of L's constituting the LED array 7.
This is an example in which the ED bare chip is mounted on the LED substrate 401 attached to the back surface of the fixed drum 4, and the LED bare chip is arranged in a semi-circular through hole 404 penetrating the fixed drum 4, and the configuration of FIG. The same effect as is obtained.

FIG. 13 shows an example in which the through hole 404 of FIG. 12 is filled with resin 405. The resin 405 may be a transparent material, a material having a large transmittance at the emission wavelength of the LED, or a resin mixed with a light diffusing agent. LEDs for linear light emission formed by LED rows
The light amount ripples corresponding to the number of ## EQU1 ## occur, but such a light amount ripple is reduced by mixing the resin 405 with a light diffusing agent to diffuse the light from the LED.

In FIG. 14, the fixed drum 4 is provided with a light diffusion sheet 406 made of a material such as resin having a large transmittance at the emission wavelength of the LED so as to cover the through hole 404 of FIG.
It is arranged on the end face of. This light diffusion sheet 40
By providing 6, the effect of reducing the light amount ripple of the LED array can be obtained as in the case of the light diffusing agent mixed in the resin 405 of FIG.

FIG. 15 shows an example in which the wall surface of the through hole 404 is formed in a tapered shape that spreads toward the LED emission direction to increase the light collection efficiency. FIG. 16 shows the wall surface of the through hole 404 in the direction opposite to the light emission direction. This is an example in which the light-collecting efficiency is increased by forming a taper shape that widens toward the end. 15 and 16 according to the VTR system.
You can use the configuration of

FIG. 17 shows a semi-annular ring shape as shown in FIG. 18 for further efficiently collecting the light of the LED array 7 above the through hole 404 of FIG. 12 and causing linear light emission over the effective recording area. This is an example in which a cylindrical lens 407 is arranged. The cylindrical lens 407 is made by injection molding a translucent resin such as acrylic, polycarbonate, amorphous polyolefin, styrene-based, urethane-based or epoxy-based,
It is attached to the end surface of the fixed drum 4 by fitting or adhesion.

FIG. 19 is an enlarged view of a part of the cylindrical lens 407 of FIG. 17, and FIG.
Shows a typical cylindrical lens known in the related art. The conventional cylindrical lens shown in FIG. 20 has a curvature of 0 in the Y direction, but the circular cylindrical lens 407 used in the present invention shown in FIG. 19 has a shape having a curvature in the Y direction. Therefore, the circular cylindrical lens 10 can efficiently collect the diverging light of the LED rows 7 and 8 and form a light arc in which the luminous flux becomes the thinnest at the focal position. The photodetectors 5 and 6 facing the LED rows 7 and 8 are placed at the focal position of the cylindrical lens 407 where the luminous flux becomes the thinnest, and the presence or absence of light at this position is detected, and a recording circuit that is a circuit mounted on the rotary drum. And control the regeneration circuit. As a result, light leakage (crosstalk) from the reproducing LED array 8 to the recording photodetector 5, which has been a problem in the past, is reduced.

The photodetectors 5 and 6 do not necessarily have to be placed at the focal position of the cylindrical lens 407, but may be placed slightly offset from the focal position depending on the amount of light ripple, the detection area of the photodetector and its sensitivity.

In the example of FIGS. 11 to 17, the fixed drum 4 itself is provided with the groove 403 or the through hole 404 and the semi-annular LED row is arranged in these, but a semi-circular member is provided in a member different from the fixed drum 4. An annular LED array may be provided and fixed to the fixed drum 4.

FIG. 21 shows an example thereof, in which the semicircular LED array 7 is arranged on the substantially disk-shaped supporting member 408, and the supporting member 4 is provided.
08 is fixed to the fixed drum 4 with a screw 409. The support member 408 is made of a metal such as aluminum or a relatively lightweight resin.

In the above example, the light collection efficiency can be further increased by making the inner wall surface of the groove 403 or the through hole 404 for collecting the light of the LED array light reflective. Further, by making the end surface of the fixed drum 4 on the side facing the rotary drum 3 a non-reflective surface by matte black coating or the like, the light from the LED array is diffusely reflected between the fixed drum 4 and the rotary drum 3 and is incident on the photodetector. Can also be prevented.

By the way, LEs constituting the LED rows 7 and 8
If D does not emit light due to failure due to life etc., VTR
It is necessary to immediately notify the system controller of the system or the operator of that fact and prompt measures such as replacement. On the other hand, since the LED array is formed by using a large number of LED bare chips, it is desirable that the intended operation be continued when a small number of LED chips such as one or two LED chips fail. Therefore, an example of the LED failure countermeasure will be described with reference to FIGS.

FIG. 22 shows a plurality of L's constituting an LED array.
EDD1 to Dx are connected in series, and current determining resistor R
a and an operation confirmation visible light LED Da are connected in series. According to this example, even if one of the LEDs D1 to Dx fails, the operation confirmation visible light LEDDa does not emit light, which is advantageous in that the failure can be immediately recognized.

FIG. 23 shows an example in which a plurality of LEDs D1 to Dx are connected in parallel via current determining resistors R1 to Rx, respectively. In this way, one or more LEs
Even if D fails, the other normal LEDs can still emit light.

FIG. 24 shows LEDDs of FIG. 23 connected in parallel.
A current adjustment resistor Rb and an operation confirmation visible light LED Da are connected in series with a parallel circuit of 1 to Dx. In this way, if even one of the LEDs D1 to Dx fails, the current Id increases and the voltage drop at the point X increases.
Since the operation confirmation visible light LEDDa is not supplied with a voltage enough to emit light and does not emit light, LEDs D1 to D
Any failure of x can be detected. In this case, an arbitrary number of LEs can be selected by selecting the value of the current adjustment resistor Rb.
The failure of D can be detected.

FIG. 25 shows an example in which a current monitoring circuit 400 is provided in place of the resistor Rb and the operation confirmation visible light LEDDa of FIG. The current monitoring circuit 400 includes LEDs D1 to Dx
The current flowing in the parallel circuit is monitored. For example, a current-magnetic field conversion circuit can be used. Also with this configuration, it is possible to detect the failure of any number of LEDs.

FIG. 26A shows a plurality of LEDs D1 to D.
This is an example in which every four x are connected in series in the arrangement direction, and FIG. 26B is a rewrite of FIG. 26A for easy understanding. In this way, groups of every four LEDs connected in series are set as 410 to 413, and the current determining resistor R1 is connected in series to each of these groups 410 to 413.
0 to R13 are connected.

In this way, even if a relatively small number of LEDs such as one or two fails, linear light emission can be performed with a predetermined light emission amount without any problem. For example, if one LED in the LED group 410 fails, the LED group 4
All LEDs of 10 are turned off, but other LED group 411
~ 413 emit light. As a result, each L of the LED group 410
Although the amount of light emission decreases at the position corresponding to ED, the amount of light emission can be compensated by increasing the power supply voltage Vcc on the system controller side. Also, L
If a constant current circuit is used as the drive source of the ED, the LED group 410
The amount of light emission can be increased by increasing the amount of current flowing through the other LED groups by the amount that is turned off and no current flows.

In FIG. 1, the recording LE is shown as an LED array.
The two rows of the D row 7 and the reproducing LED row 8 are arranged at different positions in the radial direction. However, since the photodetectors 5 and 6 can operate the same amount of received light, in order to reduce power consumption, each LED is arranged. The amount of light emitted from a row is the number of LEDs or LEDs
It is possible to match them by means such as different currents flowing through.

FIG. 27A shows a visible light LED for operation confirmation.
Instead of the photo coupler 420, the LED 421 of the photo coupler 420 (LED D1 to Dx) is used.
This is an example in which the above is detected in the LED array by the photodetector 422 of the photocoupler 420. Although the photocoupler 420 uses a phototransistor for the photodetector 421 in the illustrated example,
Other light receiving elements such as a photodiode or a photo IC may be used. The resistor R14 is the LED D1 to Dx.
The resistor R15 that determines the current flowing through the resistor R15 is a current determining resistor that determines the current flowing through the photodetector 422 when the output becomes L level during switching of the photodetector 422.

In FIG. 27A, if the voltage of the power supply Vcc2 is set to 5V, the TTL logic IC or MO
V using digital IC such as S logic IC
The output of the photocoupler 420 can be directly input to the control circuit of the TR.

The operation of FIG. 27A will be briefly described.
During normal operation, a current flows that normally causes the LEDs D1 to Dx to emit light, and the LEDs 1 to Dx emit light. At this time, the LED 421 of the photocoupler 420 is also emitting light and the photodetector 422 is turned on, so that the point Y, which is the output end of the photodetector 420, is at the L level. Next, when any one of the LEDs D1 to Dx has a disconnection failure, the current for driving the LEDs D1 to Dx stops flowing, so that the light emission is stopped and the LED 421 of the photocoupler 420 is stopped.
Also stops emitting light. As a result, the photodetector 422 of the photocoupler 420 is turned off, and the point Y becomes H level. Therefore, it can be understood that the LEDs D1 to Dx are normal when the Y point is at the L level and are defective when the Y point is at the H level. The control circuit discriminates the level at this Y point and prompts the operator
Give a failure warning.

FIG. 27 (b) shows LEDs D1 to Dx, shown in FIG. 27 (a), for easy visual inspection.
The LED 421 and the resistor R14 of the photocoupler 420
And a visible light LED Da is connected in series.

As described above, according to the embodiments of FIGS. 22 to 27, the maintenance of the LED array becomes easy, and particularly when the LED wiring method as shown in FIG. Even if several LEDs fail, it is possible to expect an effect that linear light emission can be performed with a predetermined light emission amount without any problem.

Next, it will be described that the circuit structure of the recording / reproducing system of the VTR can be simplified and downsized according to the present invention. FIG. 28 is a circuit example of a recording / reproducing system according to the present invention.
In contrast to this, FIG. 29 shows an example of a conventional circuit.
In each case, the winding angle of the magnetic tape on the rotating drum is 18
In this example, the heads are arranged at 0 °, the number of heads on the rotary drum is 16, and two heads are arranged so as to face each other by 180 °.

In the recording system shown in FIG. 28A, the input image signal is digitized by the A / D converter 101 and then distributed to eight encoders 102 to be encoded. The eight-divided signals are sequentially input to the fixed-side element of eight channels of the rotary transformer 105 via the modulator 103 and the rotary transformer driver 104. The recording amplifier 10 is connected to the eight rotating elements of the rotary transformer 105.
Sixteen recording heads 107 are connected to each two via six. On the other hand, in the case of the prior art, as shown in FIG. 29A, a rotary transformer having 16 rotary side elements for 16 heads, 16 encoders, modulators and rotary drivers. Will be needed.

On the other hand, also in the reproducing system shown in FIG. 28B, in the case of the present invention, with respect to 16 reproducing heads 122,
The rotating-side element and the fixed-side element of the rotary transformer 120 may be half, that is, eight, and the rotary transformer receiver 11 at the subsequent stage may be used.
9, the equalizer 118, the AGC circuit 117, and the comparator 116 for binarization may be eight. On the other hand, in the case of the conventional technique, as shown in FIG. 29B, the rotary transformer receiver 119, the equalizer 11
8, 16 AGC circuits 117 and 16 comparators 116 are required. Further, in the case of the conventional example, a mixing circuit (not shown) for mixing the reproduced signals from the heads facing each other by 180 ° is required between blocks 116 to 118. The data identification circuit 113 to the D / A converter 108
The configuration up to here is basically the same between FIG. 28 (b) and FIG. 29 (b).

FIG. 30 shows another configuration example of the recording circuit 13a. The recording circuit 13b has the same configuration. In this embodiment, the recording photodetector 5 (5
a) and a detector amplifier 501 for amplifying the output thereof and a comparator 502 for binarizing the output of the amplifier 501 are included in the recording circuit 13a, and these are mounted in one hybrid IC. Hereinafter, this hybrid IC will be referred to as a recording circuit IC.

FIG. 31 shows a mounting example of the recording circuit IC.
IC bare chip 5 in which the recording circuit 13a of FIG. 30 is integrated
10 is fixedly mounted on the lead frame 511 with a conductive adhesive, wiring is performed from the pad of the IC bare chip 510 to the lead portion of the lead frame 511 via the bonding wire 512, and the whole is transfer molded to form a package 513. There is. The resin material of the package 513 may be transparent, but a special resin that transmits light having a specific wavelength may be used, or a resin that transmits only light having the highest sensitivity wavelength of the photodetector may be used. Further, a resin material that transmits only infrared light and cuts visible light that causes disturbance may be used. In this case, the LEDs of the LED row 7 that emits control light are also adjusted to the wavelength transmission characteristics of the resin material of the package 513.

In FIG. 32, a lens 514 is formed on the package 513 of FIG. 31 to collect the control light from the LED on the photodetector 5 in the IC bare chip 510.

FIG. 33 shows a VTR of the recording circuit IC of FIG.
FIG. 6 is a cross-sectional view showing an example when mounted on the scanner of FIG. The scanner 1 comprises a rotating drum 3, an upper fixed drum 4a and a lower fixed drum 4b, and the rotating drum 3 has a bearing 5
It is fixed to a rotary shaft 520 supported by 21, 522, and is rotationally driven by a drum motor 523.

The recording RF signal is transmitted from the fixed side element 524 of the rotary transformer 17 to the rotary side element 525, as shown in FIG.
It is input to the recording circuit ICs 526a and 526b having the configuration shown in FIG. The terminals of the recording circuit ICs 526a and 526b are fixed to the circuit board 527 by soldering. The output terminal of the recording circuit IC 526a is soldered to one end of the lead wire 528a, and the other end of the lead wire 528a is soldered to the relay substrate 529a of the head winding bonded to the head base of the recording head R1. 529
It is connected to the recording head R1 via a. The same applies to the recording circuit IC 526b.

As described above, by incorporating the photodetector 5 and the detector amplifier 501 and the comparator 502 attached thereto in the recording circuit IC, the number of parts in the rotary drum 3 is greatly reduced, and the mounting density in the rotary drum 3 is reduced. Has the advantage of being significantly improved.

Similarly, for the reproducing circuit and the erasing circuit, the photodetector and its accompanying circuit can be incorporated in the same hybrid IC.

There are various possible implementations of the hybrid IC including the photodetector and its accompanying circuits. For example, each IC of a recording circuit, a reproducing circuit, and an erasing circuit.
It is also possible to mold into a normal plastic package and configure the photodetector with a bare chip to form a hybrid IC.

On the other hand, as another mounting technique, a hybrid IC is used.
Circuit integration technology called a multi-chip package that can be said to be intermediate between the above and the monolithic IC
There is a method). The MCP method is described in, for example, "VLSI LSI Dictionary" p797-P798, Yasuo Tarui, published by Science Forum.

FIG. 34 is a sectional view schematically showing the internal structure of the package when the MCP method is applied to the present invention. In this mounting method, a plurality of ICs or discrete elements, that is, bare chips in different semiconductor processes, and passive elements such as capacitors and resistors are made into silicon chips by devising a lead frame in a conventional IC package.
The wirings are interconnected on a wiring board on a lead frame and then packaged by transfer molding.

The structure and manufacturing method will be briefly described. First, the wiring board 6 is mounted on the lead frame 600 of the IC.
01 is attached with an adhesive 602, and an IC 603 such as a recording circuit of a bare chip and a photodetector 604 are fixedly mounted thereon with a conductive adhesive 605. These are wiring boards 6
A wiring is connected by a bonding wire 607 via a wiring pattern 606 on 01 to form a circuit. Then, transfer mold sealing is performed to form a hybrid IC package 608. The lens 609 for condensing the light from the LED may also be integrally molded with the package 608.

The system in which the recording circuit, the photodetector, and the circuits associated therewith are mounted on the same hybrid IC as described above can be applied to scanners of other systems. 35A and 35B show an example in which the present invention is applied to a scanner using another method. FIG. 35A is a sectional view and FIG. 35B is a schematic plan view. When the same reference numerals are given to the portions corresponding to those in FIG. 1, the control of a recording circuit (not shown) is performed by the recording LEDs 7a,
7b and the photodetectors 5a and 5b for recording. Note that the reproducing and erasing LEDs and the photodetector are omitted. Photo detectors 5a and 5b
Is arranged on the rotary drum 3 inside one of the recording heads R1 and on the same straight line in the radial direction passing through R1.
The LEDs 7a and 7b are arranged on the fixed drum 4 such that the positions from the center of the rotary drum 3 are displaced in the radial direction so that they can face the photodetectors 5a and 5b, respectively.

The outputs of the photo detectors 5a and 5b are the detector amplifiers 501a and 501b as shown in FIG.
After being amplified by, and binarized by the comparators 502a and 502b, they are input to the set terminal and the reset terminal of the RS flip-flop 503, respectively. As will be described later, the photo detectors 5a and 5b and the circuit shown in FIG. 36 attached thereto are mounted in the same IC as the recording circuit.

The operation of this embodiment will be described. First, LE
It is assumed that D7a and 7b are controlled by the control circuit 9 to emit light. In the state of FIG. 35, the photo detector 5
Since a and the LED 7a face each other, an H level signal is output from the photodetector 5a. Therefore, RS
The Q output of the flip-flop 503 becomes H level. Next, when the rotary drum 3 rotates in the direction of the arrow, the output of the photodetector 5a becomes L level, and when the rotary drum 3 further rotates 180 °, the output of the photodetector 5b becomes L level, so that the Q of the RS flip-flop 503 is changed.
The output becomes L level.

Hereinafter, the Q output of the RS flip-flop 503 is sequentially set to H level and L every 180 ° rotation of the rotary drum 3.
Repeat levels alternately. This RS flip-flop 5
The Q output of 03 is input to the AND gate 25 as a 180 ° switching signal instead of the output of the comparator 502 of FIG. 30, and when this is at H level and the recording RF signal is detected, the amplifier 27 of the output stage is in the active state. In all other cases, the state is inactive. In Figure 37, this 180 °
4 shows a sequence of switching circuits.

38A and 38B show an example in which the present invention is applied to a scanner using still another method. FIG. 38A is a sectional view and FIG. 38B is a schematic plan view. When the same reference numerals are given to the portions corresponding to those in FIG. 1, the control of the recording circuit (not shown) is performed by the reflection type photosensors 701a and 701b arranged inside the recording heads R1 and R2 on the rotary drum 3. Done. On the other hand, on the fixed drum 4 side, half of the surface facing the rotating drum 3 (recording area side) is a reflecting surface by disposing a mirror or the like, and the other half (non-recording area side) is detected by the reflective photosensors 701a and 701b. Impossible non-reflective surface.

The reflective photosensors 701a and 70a
1b is an LED 702 and a photodetector (phototransistor or photodiode) as shown in FIG.
Are integrated, for example, the H level is output when there is a reflecting object on the facing surface, and the L level is output when there is no reflecting object.

The operation of this embodiment will be briefly described. The recording circuit (not shown) connected to the recording head R1 is controlled by the reflection type photo sensor 701a, and the rotary drum 3 is operated.
With the rotation of the disk, it is in the active state while passing through the recording area side with the reflection surface, and conversely, is in the inactive state on the non-reflection surface side. Similarly, the reflective photosensor 701b controls the active / inactive state of the recording circuit connected to the recording head R2.

Next, a mounting example of the recording circuit and the reflection type photosensor in this embodiment will be described. As shown in FIG. 40, the recording circuit and the reflective photosensor are mounted on the same hybrid IC.

That is, the wiring board 801 is attached to the lead frame 800 of the IC with the adhesive 802, and the IC 803 such as the recording circuit of the bare chip, the LED 804, and the photodetector 805 are fixedly mounted on the lead frame 800 with the conductive adhesive 806. These are connected by a bonding wire 808 via a wiring pattern 807 on the wiring board 801 to form a circuit. Then, transfer mold sealing is performed to form a hybrid IC package 809.

As described above, according to the embodiments shown in FIGS. 30 to 40, since the photodetector and the circuit associated therewith are mounted in the same hybrid IC together with the recording circuit, the number of parts of the rotary drum 3 is greatly reduced. However, there is an advantage that the mounting density of the rotary drum 3 is significantly improved. This effect is particularly remarkable in the case of a VTR having a large number of heads and a large rotary drum-mounted circuit such as a digital VTR for HDTV.

FIG. 41 is a block diagram showing another structural example of the recording circuit having the carrier detecting function. In this embodiment, as the RF detector which is the information signal detecting means,
A full-wave rectification type RF detector 20 is used. That is, the recording RF signal transmitted from the rotary transformer (not shown) is input to the input 1 and the input 2 of the recording circuit 13a. The input recording RF signal is amplified by an amplifier 21a and then branched into two, one to a full-wave rectification recording RF detector 20 and the other to an amplifier 27 via an amplifier 21b.
Entered in. The full-wave rectification type RF detector 20 is configured using a full-wave rectification circuit, and when a recording RF signal is detected,
An H (high) level signal is output to the AND gate 25 in the next stage.

The photodetector and its accompanying circuit may be incorporated in the IC of the recording circuit 13a shown in FIG. 41 as in the case of FIG.

FIG. 42 shows a full-wave rectification type RF detector 20.
FIG. 3 is a diagram showing a configuration example of, which includes a full-wave rectifier circuit 28, a low-pass filter 29, and a comparator 24. The operation of the RF detector 20 will be described with reference to the waveform chart of FIG. Note that, here, for simplification of description, the RF signal input to the RF detector 20 is a sine wave.

The RF signal shown in FIG. 43 (a) is full-wave rectified by the full-wave rectifier circuit 28 as shown in FIG. 43 (b), so that the low-frequency component and high-frequency component lower than the fundamental frequency of the RF signal are obtained. Is converted to and. The output of the full-wave rectifier circuit 28 is input to the low-pass filter 29, high-frequency components are removed, and only low-frequency components are extracted.
The output shown in (c) is obtained. This low pass filter 2
The output of 9 is input to the comparator 24 and binarized.

Full wave rectification type RF detector 2 shown in FIG.
0 has the following advantages over the RF detector including the detector amplifier 22, the peak detector 23 and the comparator 24 in the recording circuit 13 shown in FIG. When the peak detector (peak hold circuit) 23 is used, the peak hold time constant due to the holding capacitor in the peak detector 23 and the input resistance of the comparator 24 is set to a value sufficient to peak hold the lowest frequency component in the RF signal. You have to choose. If this time constant is not large enough, the peak detector 23 will output RF
The ripple corresponding to the signal appears directly and the comparator 24
The binary signal output from the device also changes corresponding to this ripple. Therefore, the output off circuit 26 may cause the amplifier 27 to alternately switch to the active / inactive state in response to the above ripple even during the input period of the RF signal.

Since the input resistance of the comparator 24 is usually not so large in the bipolar process, in order to increase the peak hold time constant, the peak detector 2
It is necessary to increase the capacity of the holding capacitor in the circuit 3. If this holding capacitor is to be formed in the IC, the chip size of the IC will be increased. Otherwise, an external capacitor will be required, and in any case there is a disadvantage in terms of mounting area.

On the other hand, the RF detector 20 shown in FIG.
Then, after the RF signal is converted into a low-frequency component and a high-frequency component with respect to the fundamental frequency by the full-wave rectification circuit 28, the low-pass filter 29 removes the high-frequency component and inputs it to the comparator 24. Has become. Therefore, the cutoff frequency of the low-pass filter 29 can be made higher than the fundamental frequency of the RF signal, so that the capacity of the capacitor used for the low-pass filter 29 can be made smaller than the capacity of the holding capacitor used for the peak detector 23, and this capacitor can be Even if it is formed in the IC, the chip size is not increased. Further, since the charging / discharging time is shortened due to the decrease in the capacitance of the capacitor, the detection speed of the RF signal can be increased.

In the case of a digital VTR for HDTV, "Broadcasting Technology" 1990, VOL. 43, No. December and November extra edition p. 20-p. 26 and p. 62-p. 6
As described in No. 6, the recording rate per magnetic head is 148.5 Mbps. The recording modulation method uses the 8-8 conversion ASE code to suppress the low frequency component as much as possible, but the low frequency component is not completely excluded. Therefore, the RF detector must be able to detect RF signals over a wide band from low band to 148.5 Mbps. Further, in the case of a digital VTR for HDTV, the circuit mounting area of the circuit on the rotary drum is considerably restricted due to the use of an extremely large number of magnetic heads such as 18 as described above, and therefore, the RF detector must be integrated into an IC. It is a condition, and the chip size is desired to be as small as possible. The full-wave rectification type RF detector 20 having the above-described configuration can easily meet these requirements.

FIG. 44 is a full-wave rectification type RF detector 20.
It is a figure which shows the other structural example of a full wave rectification circuit 28a,
It differs from the example of FIG. 42 in that it has a two-stage configuration of 28b. FIG. 45 is an operation waveform diagram of the RF detector 20 of FIG. The RF signal shown in FIG.
The full-wave rectification circuit 28a of the second stage performs full-wave rectification as shown in FIG. 45 (b), and the full-wave rectification circuit 28b of the second stage performs full-wave rectification as shown in FIG. 45 (c). At 29, high frequency components are removed as shown in FIG.

As is apparent from FIGS. 45 (b) and 45 (c), the high frequency component in the output of the second-stage full-wave rectifier circuit 28b is higher than that of the output of the first-stage full-wave rectifier circuit 28a. It has been converted to high frequency components. That is, by performing the full-wave rectification in two stages in this manner, the capacitance of the capacitor used for the low-pass filter 29 can be further reduced as compared with the case where the full-wave rectification circuit has one stage (FIG. 42).

FIG. 46 shows a full-wave rectification type RF detector 20.
FIG. 44 is a diagram showing another configuration example of the high pass filter 30 between the two-stage full-wave rectifier circuits 28 a and 28 b in FIG. 44.
Have been inserted. FIG. 47 shows the RF detector 2 of FIG.
It is an operation waveform diagram of 0. The RF signal shown in FIG. 47 (a) is full-wave rectified by the first-stage full-wave rectifier circuit 28a as shown in FIG. 47 (b), and then passed through the high-pass filter 30 to obtain a high-frequency signal as shown in FIG. 47 (b). Only the components are extracted. The output of the high-pass filter 30 is further full-wave rectified by the second-stage full-wave rectifier circuit 28b as shown in FIG. 47 (d), and then the high-pass component is removed by the low-pass filter 29 as shown in FIG. 47 (e). To be done.

The high-pass filter 30 can enhance the effect of full-wave rectification by the second-stage full-wave rectifier circuit 28b by cutting the DC component of the output of the first-stage full-wave rectifier circuit 28a. Further, the high pass filter 30
Also has the effect of increasing the response speed of the output (e) of the low-pass filter 29 to the RF signal (a), particularly the rising response speed. Since the capacitor used for the high pass filter 30 does not require a large capacitance, there is almost no obstacle to downsizing the IC chip.

FIG. 48 shows a full-wave rectification type RF detector 20.
FIG. 43 is a diagram showing another configuration example of FIG. 42, in which a limiter amplifier 70 is arranged in the preceding stage of the full-wave rectifier circuit 28 in FIG. 42. FIG. 49 is an operation waveform diagram of the RF detector 20 of FIG. The amplitude of the sine-wave RF signal shown in FIG. 49A is limited by the limiter amplifier 70, so that the waveform is shaped into a square wave having steep rising and falling edges as shown in FIG. 49B. The output of the limiter amplifier 70 is full-wave rectified by the full-wave rectifier circuit 28 as shown in FIG. 49 (c), and the high-pass component is removed by the low-pass filter 29 as shown in FIG. 49 (d). It is input to 24 and binarized.

As is clear from comparison between FIG. 43 (b) and FIG. 49 (c), the ripple contained in the output of the full-wave rectifier circuit 28 is smaller in the case of FIG. In FIG. 42, the input of the full-wave rectifier circuit 28 is a sine wave, whereas in FIG.
In the case of 8, the input of the full-wave rectification circuit 28 is converted into a square wave. Therefore, according to the configuration of FIG. 48, the capacitance of the capacitor used in the low-pass filter 29 for removing the ripple included in the output of the full-wave rectifier circuit 28 can be further reduced.

The configuration of the full-wave rectification type RF detector 20 of FIG. 48 is effective not only for sinusoidal RF signals but also for square wave RF signals such as NRZ signals. Such a square wave RF signal has a blunted waveform due to the lack of a DC component when passing through the rotary transformer, but can be returned to a square wave by the limiter amplifier 70.

This effect will be described with reference to FIG. Figure 50
[Fig. 4] is an operation waveform diagram when the input RF signal is a square wave. The RF signal is an NRZ signal as shown in 20 (a), and when it passes through the rotary transformer, it becomes a signal lacking the DC component as shown in FIG. 50 (b). This FIG. 50 (b)
50 RF signal is input to the limiter amplifier 70, and
It is shaped into a square wave as shown in (c). Hereinafter, the output of the limiter amplifier 70 is full-wave rectified by the full-wave rectifier circuit 28 as shown in FIG. 50 (d), and the ripple is removed by the low-pass filter 29 as shown in FIG. 50 (e). Is entered.

As described above, according to the configuration of FIG. 48, the RF signal can be correctly detected regardless of the type of the waveform of the RF signal.

The limiter amplifier 70 shown in FIG.
It goes without saying that the same effect can be obtained even if the positions of the full-wave rectification circuit 28 are exchanged.

FIG. 51 shows a full-wave rectification type RF detector 20.
It is a figure which shows the other structural example. In this example, the RF of FIG.
A means for removing the high-frequency component after full-wave rectification in the detector 20 is realized without using the low-pass filter 29. In FIG. 51, the output of the full-wave rectifier circuit 28 is first input to the comparator 24, and then processed by the delay circuit 71 and the OR gate 72. 52 is an operation waveform diagram of the RF detector 20 of FIG.

The RF signal shown in FIG. 52A is sequentially processed by the limiter amplifier 70 and the full-wave rectifier circuit 28 as shown in FIGS. 52B and 52C as in the case of FIG. The output of the full-wave rectifier circuit 28 shown in FIG. 52 (c) is binarized by the comparator 24 as shown in FIG. 52 (d). The output of the comparator 24 is branched into two, one of which is input to the delay circuit 71 and delayed as shown in FIG. 52 (e), and the other is given to one input of the OR gate 72. The output of the delay circuit 71 is given to the other input of the OR gate 72. As the output of the OR gate 72, an RF signal detection output as shown in FIG. 52 (f) is obtained.

According to the example of FIG. 51, a low-pass filter and a high-pass filter are unnecessary, so that FIG.
The response speed of the RF signal detection output of FIG. 52 (f) to the RF signal of FIG.

Next, a recording circuit according to another embodiment of the present invention will be described. In this embodiment, a code for designating a recording circuit for recording the information signal to be recorded (referred to as a recording circuit designating code) is added,
The recording circuits 13a and 13b have a function of determining the recording circuit designation code. The recording circuit designation code depends on the number of circuits mounted on the rotary drum, but for example, simply 2
It is converted into a bit binary signal and added to the recording information signal. When the number of circuits mounted on the rotary drum increases, the recording circuit designating code may be multi-bit such as 3 bits or 4 bits, or may be added to the recording information signal in a modulated form. FIG. 53 is a diagram showing a specific example of a recording circuit having such a function. Although the recording circuit 13a is shown here, the recording circuit 13b has the same configuration.

In FIG. 53, the recording RF signal transmitted from the rotary transformer (not shown) is the recording circuit 13.
It is given to input 1 and input 2 of a. Recorded RF input
The signal is branched into two, one of which is input to the emitter follower 31 for current-amplifying the recording RF signal, and the other of which is input to the code detection amplifier 32. The code detection amplifier 32 has a recording R
The F signal is amplified so as to have a predetermined signal amplitude and sent to the comparator 33 at the next stage. The comparator 33 compares the input recording RF signal with an appropriate threshold value, binarizes it, and sends it to the code identification circuit 34. The code identification circuit 34 stores and holds the unique code defined in the recording circuit 13a, compares this code with the recording circuit designation code in the binarized recording RF signal from the comparator 33, and When the codes match, an H (high) level signal is output to the output off circuit 35 of the next stage as a match determination signal.

As described above, the recording circuit 13a is equivalent to the recording circuit 1
When the recording RF signal to which the same recording circuit designating code as the code unique to 3a is added is input, the code detecting amplifier 32, the comparator 33 and the code identifying circuit 34 are provided.
To the output off circuit 35 by the code detection circuit consisting of
Output level signal. On the contrary, when the recording RF signal added with the recording circuit designation code different from the code unique to the recording circuit 13a is input, the code detection circuit outputs the L level signal to the output off circuit 35. The output of the output off circuit 35 is supplied to the amplifier 36 as a control signal. The amplifier 36 further amplifies the recording RF signal current-amplified by the emitter follower 31, and outputs the amplified recording RF signal to the output 1 and the output 2.

54 and 55 show the operation sequences of the respective circuit units inside and outside the recording circuit 13a of FIG. 53 during normal recording and insert recording. When the recording circuit designating code, which is the same as the code uniquely possessed by the recording circuit 13a, is added to the recording RF signal and input to the recording circuit 13a, a code detection circuit including a code detection amplifier 32, a comparator 33 and a code identification circuit 34. Outputs an H level signal to the output off circuit 35. At this time, the output OFF circuit 35 activates the amplifier 36 at the output stage of the recording circuit 13a, and the amplifier 36 supplies a recording current corresponding to the recording RF signal to the magnetic head (not shown).

On the contrary, when a recording circuit designating code different from the code unique to the recording circuit 13a is added to the recording RF signal and input, a code detecting circuit comprising a code detecting amplifier 32, a comparator 33 and a code identifying circuit 34. Outputs an L level signal to the output off circuit 35, the amplifier 36 is deactivated by the output off circuit 35 as shown in FIG. As a result, the recording RF signal output is stopped, and the amplifier 36 enters a state in which no recording current is supplied to the magnetic head.

At the time of insert recording, a recording circuit designating code is added to the recording information signal to be insert-recorded and transmitted to the recording circuits 13a and 13b through the rotary transformer commonly connected to the recording circuits 13a and 13b. Thus, a recording RF signal is output. Therefore, as can be seen from the example of FIG. 55, partial rewriting is possible only by adding a recording circuit designating code to the portion for insert recording and transmitting the RF signal for insert recording.

Also in this embodiment, the same effect as that of the previous embodiment can be obtained, and the circuit structure of the recording / reproducing system of the VTR can be simplified and downsized. The configuration of the amplifier unit of the recording circuits 13a and 13b may be the configuration shown in FIG.

FIG. 56 shows another example of the configuration of the recording circuit 13a having the function of determining the recording circuit designation code. The code detecting amplifier 32, the comparator 33 and the code identifying circuit 3 are shown in FIG.
In order to prevent malfunction of the code detection circuit composed of 4, a carrier detection circuit 37 for detecting the presence / absence of a recording information signal is added. In this example, the AND gate 38 performs a logical product of the output of the code identification circuit 34 of the code detection circuit and the output of the carrier detection circuit 37, and the output of the AND gate 38 controls the output off circuit 35.
The recording circuit designating code peculiar to the recording circuit 13a only when both the code and the carrier are detected, the amplifier 36 at the output stage of the recording circuit 13a is activated.

As another configuration, the AND gate 35 is not used, and the output of the carrier detection circuit 37 is used to detect the code detection amplifier 32, the comparator 33, and the code identification circuit 34.
By directly controlling the code detection circuit consisting of
It is also possible to prevent malfunction of the code detection circuit.

Further, in the above embodiment, the circuit in which the code detecting circuit is added to the recording circuit has been described, but a similar code detecting circuit may be added to the erasing circuit. in this case,
By inputting the erasing signal to which the erasing circuit designating code is added to the erasing circuit at the timing of erasing, it is not necessary to use the LED array for controlling the erasing circuit, and the same effect as in the case of the recording circuit can be obtained.

Further, although the recording circuit designating code is added only to the head of the recording information signal in the above embodiment, in order to simplify the configuration of the code identifying circuit and to clarify the recording range of the recording information signal, It is also possible to add the recording circuit designation code to the beginning and the end of the recording information signal. By expanding this, a recording circuit designation code and a code indicating the beginning of the recording information signal are added to the beginning of the recording information signal, and a code indicating the end of the recording information signal is added to the end of the recording information signal. Good.

Further, when transmitting the recording circuit designating code and the recording information signal from the outside to the inside of the rotary drum, the rotary transformer is usually used as described above. Since it is difficult to transmit a low frequency on a rotating drum, it is very effective to prevent an error in signal transmission by modulating or converting to a frequency with good transmission efficiency.

A parity signal or a sync signal for facilitating the detection and synchronization of the code may be added to the recording circuit designating code.

Furthermore, if a system for reproducing both the recording circuit designating code and the recording information signal is used, for example, if the recording circuit designating code is not reproduced during normal reproduction, a failure of the circuit or the magnetic head is considered. Can be notified to the system controller to notify the VTR operator by a display or the like to prompt repair.

Next, the reproducing circuits 14a and 14b will be described. The reproducing circuits 14a and 14b are the reproducing heads P1 and P.
2 has a so-called carrier detection function of detecting the presence or absence of a reproduction information signal (referred to as a reproduction RF signal) reproduced by 2. FIG. 57 is a diagram showing a specific example of a reproducing circuit having such a carrier detecting function. Although the reproduction circuit 14a is shown here, the reproduction circuit 14b has the same configuration.

In FIG. 57, the reproduction RF signal reproduced by the reproduction head P1 is input to the input 1 and the input 2. Since the input reproduction RF signal is a minute signal voltage, it is first amplified by the head amplifier 41 which is a low noise and high gain amplifier, and then branched into two, one of which is the detector amplifier 42.
Entered in. The detector amplifier 42 amplifies the reproduced RF signal to a sufficient signal amplitude, and the peak detector 4 of the next stage is amplified.
Send to 3. The peak detector 43 receives the input reproduction RF.
The peak of the signal is detected and the detection signal voltage corresponding to the peak value is output. The detection signal voltage output from the peak detector 43 is input to the comparator 44. When the input detection signal voltage exceeds a predetermined threshold value, the comparator 44 causes the output-off circuit 45 of the next stage to be H (high).
Output level signal.

As described above, the reproduction circuit 14a receives the reproduction RF signal having a predetermined amplitude level or more, the detector amplifier 42, the peak detector 43, and the comparator 4.
An H level signal is output to the output off circuit 45 by the RF detector composed of 4. On the other hand, when the reproduced RF signal amplitude equal to or lower than the predetermined amplitude level is input, the RF detector outputs an L (low) level signal to the output off circuit 45. The output of the output off circuit 45 is supplied to the amplifier 46 as a control signal. The amplifier 46 further amplifies the reproduction RF signal that has been current-amplified by the head amplifier 41 and outputs it to the output 1 and the output 2.

FIG. 58 shows an operation sequence of each circuit unit inside and outside the reproducing circuit 14a at the time of normal reproduction in this embodiment. When the output of the comparator 44 becomes H level, the amplifier 46 is turned on by the output off circuit 45, that is, the reproduction circuit 13a is activated, and the reproduction RF signal is output. The amplifier 46 drives a rotary transformer (not shown) and transmits the reproduction RF signal to the outside of the rotary drum.

On the contrary, when the output of the comparator 44 becomes the L level, the output off circuit 45 causes the reproduction circuit 13a.
However, the amplifier 45 is deactivated. As a result, the reproduced RF signal is not transmitted outside the rotary drum.

FIG. 59 shows another example of the structure of the reproducing circuit 14a having the carrier detecting function, which is configured in consideration of special reproduction such as fast-forward reproduction. Before explaining FIG. 59, a case where fast-forward reproduction is performed in the reproducing circuit 14 shown in FIG. 57 will be described. FIG. 58 shows a series of time sequences in this case. Figure 5
By adding the RF detector composed of the detector amplifier 42, the peak detector 43 and the comparator 44 to the reproducing circuit 14a of No. 7, the reproducing RF signal having a predetermined amplitude level or less is not output from the reproducing circuit 13a.

Usually, in a digital VTR, for example, the S / N (signal-to-noise ratio) of the reproduced RF signal is below a predetermined value (20 dBp-p / rms = 3 × 10 ^-7 , which is a practical limit for error correction). Reference: “Introduction to Magnetic Recording Technology” by Katsuya Yokoyama), the error rate of digital signals deteriorates. Therefore, a predetermined amplitude level and a predetermined S /
Reproduced RF signals of N or less are discarded without being used. Therefore, fast forward playback, fast reverse playback, slow playback,
When special playback such as double speed playback and reverse playback is performed, setting the detection level of the above RF detector to a level at which a predetermined S / N is obtained eliminates the need to cut off the playback RF signal in the subsequent circuit. , The circuit for rounding down is unnecessary.

However, depending on the system, a reproduction RF signal having an S / N of not more than a predetermined value may be required. For example, even if the error rate deteriorates, it can be used as reference data for other reproduced signals,
Further, since the tape running servo during special reproduction is performed by the envelope of the reproduction RF signal, it may be necessary to transmit all the reproduction RF signals to the reproduction signal processing circuit.

FIG. 59 is a block diagram of a reproducing circuit 13a suitable for such a case. In the reproducing circuit to which the RF detector shown in FIG. 57 is added, the special reproducing for controlling the output signal of the RF detector from the outside of the reproducing circuit. R by the switching signal input terminal and the special playback switching signal input from this terminal
An OR gate 47 for masking the output signal of the F detector is added.

FIG. 60 is an operation sequence of the reproducing circuit of FIG. 59, and schematically shows a state in which the VTR is in the fast-forward reproduction. The operation of the RF detector is the same as that of the reproducing circuit shown in FIG. The detection signal of the RF detector, that is, the output signal of the comparator 44 is output as in the case of FIG. This detection signal (X) is applied to the OR gate 4
In FIG. 7, the special reproduction switching signal input (Y) is masked so that it is not transmitted to the output off circuit 45.

In the example of FIG. 59, the detection signal of the RF detector is masked by the OR gate 47, but the special reproduction switching signal input (Y) directly controls the comparator 44, the peak detector 43 or the detector amplifier 42. Therefore, the amplifier 46 at the output stage of the reproducing circuit 14a may be controlled to the active state via the output off circuit 45.

The special reproduction switching signal input (Y) controls the RF detector, and reproduces the reproduction circuits 14a and 1 every 180 °.
4b must be switched, but L described in the conventional example
The three methods proposed in Japanese Patent Application No. 1-127911 including the method using the ED train can be applied without changing the method and circuit. Further, the control signal may be transmitted via the rotary transformer.

In general, an information signal reproduced from a magnetic tape by a magnetic head may cause dropout due to a momentary increase in spacing between the tape and the head due to a defect or dust on the tape. The influence of this dropout is visually noticeable and becomes a serious problem particularly during normal reproduction.

According to the embodiment of FIG. 57 described above, similarly to the case of the special reproduction, the reproduction information signal when the dropout occurs due to the RF detector is detected and is not output from the reproduction circuit 13a. Can be In this case, for example, the output signal of the RF detector may be masked by a retriggerable multivibrator circuit or the like so that the output off circuit 45 does not respond to the short-time dropout.

The reproducing circuit 14 shown in FIGS. 57 and 59 is used.
In a, the RF detector, that is, the information signal detection circuit is constituted by the detector amplifier 42, the peak detector 43 and the comparator 44. However, like the recording circuit 13a shown in FIG. 41, the full wave as described in FIGS. A rectification type RF detector may be used.

Next, another configuration example of the recording circuits 13a and 13b will be described.

Generally, in a digital VTR, various number codes peculiar to a recording format are recorded in a recording information signal, that is, a sync block number in a sync block and a sector ID.
Codes representing track numbers, segment numbers, field numbers, etc. are added. Therefore, by detecting at least one of these number codes, it is determined whether or not it matches the unique code defined in each recording circuit, and by using the determination result, the recording circuit 13
It is possible to switch active / inactive of a and 13b. FIG. 62 is a diagram showing a configuration example of a recording circuit having such a number code determination function. Here, the recording circuit 1
3a, the recording circuit 13b has the same configuration.

In FIG. 62, the information signal to be recorded (recording RF signal) transmitted from the rotary transformer (not shown) is inputted to the input 1 and the input 2 of the recording circuit 13a. The input recording RF signal is branched into two, one of which is an emitter follower 5 for current-amplifying the recording RF signal.
1 is input to the amplifier 52. The RF signal amplified to a predetermined signal amplitude by the amplifier 52 is branched into two, and one of them is input to the comparator 53. The comparator 53 compares the input recording RF signal with an appropriate threshold value, binarizes it, and sends it to the memory 54 for recording timing adjustment and the code detection circuit 55. The other of the recording RF signals amplified by the amplifier 52 is sent to the signal amplitude detection circuit 56. The signal amplitude detection circuit 56 is composed of, for example, a peak detector, detects the signal amplitude of the input recording RF signal, and controls the amplifier 57 at the final stage to a gain corresponding to the signal amplitude. As the amplifier 57, for example, a normal AGC amplifier is used.

The code detection circuit 55 stores and holds the unique code defined in the recording circuit 13a, and a predetermined number code added to this code and the binarized recording RF signal from the comparator 53. Are compared, and when both codes match, a match determination signal is output to the memory 54. As a result, the recording RF signal output from the memory 54 is controlled by the signal amplitude detection circuit 56 to have a gain corresponding to the input signal amplitude.
Is output to the recording head R1 via.

Thus, when the same code as the code unique to the recording circuit 13a is added as a number code to the recording RF signal and input, the code detection circuit 55 causes the memory 54 to output the recording RF signal. Is amplified by the amplifier 57 and output to the recording head R1.

Conversely, when a code different from the code unique to the recording circuit 13a is added to the recording RF signal and input, the code detection circuit 55 does not output the recording RF signal to the recording head R1.

63 and 64 show the operation sequences of the respective circuit units inside and outside the recording circuit 13a of FIG. 62 during normal recording and insert recording.

Next, the code detection circuit 55 in FIG.
Of the actual digital VTR
The recording format will be described as an example.

65 to 67 are diagrams for explaining the D-2 format, which is one of the formats for recording the digital signal of the NTSC composite signal. The magazine "Broadcasting Technology" published in November, 1990. It is a quotation from the special issue of November, Vol. 43, No. 12. FIG. 65 shows the data structure of the helical track, and FIG. 66 shows the sync block I.
D format, and FIG. 67 shows sync block ID numbers. As shown in FIGS. 65 to 67, the video signal and the audio signal are converted into digital signals, and then an error correction code and various identification signals are added and recorded on a magnetic tape.

In the present embodiment, the number codes such as the track number, segment number and field number shown in FIG. 66 are detected by the code detection circuit 55 shown in FIG. 62, and a match / mismatch with a predetermined unique code is obtained. The judgment signal controls the active / inactive state of the recording circuit 13a. However,
Since these number codes are present in the signals to be recorded as shown in FIGS. 65 to 67, if the recording circuit 13a is activated and the recording operation is started after detecting these number codes, the recording timing will be changed. It is delayed and the correct recording is not done. Therefore, in this embodiment, the memory 54 for adjusting the recording timing is incorporated into the recording circuit 13a, and the recording RF signal transmitted via the rotary transformer is transmitted as shown in the operation sequence of FIGS. From the actual recording timing, for example, the drum rotation angle is 18
The timing is advanced by 0 ° and input to the recording circuit 13a, and the emitter follower 51, the amplifier 52 and the comparator 5 are input.
Then, the data is temporarily stored in the memory 54 via step 3. Then, after the code detection circuit 55 detects the number code, the recording RF signal is output from the memory 54 at the recording timing of the recording head and recording is performed via the amplifier 57.

As shown in FIG. 62, the comparator 5
Once the recording RF signal is once converted into a binary signal in step 3, it becomes difficult to control the recording current supplied to the recording head from the outside of the rotary drum. Therefore, in FIG. 62, the recording current is controlled from outside the rotary drum by varying the gain of the amplifier 57 at the final stage in accordance with the amplitude of the recording RF signal input by the signal amplitude detection circuit 56. .

In the recording circuit 13a shown in FIG. 62, the comparator 53, the amplifier 54, the code detection circuit 5
5 and the signal amplitude detection circuit 56 are added to the structure of a normal recording circuit. However, since these circuits can be integrated into an IC, it is easy to mount the recording circuit 13a in the rotary drum.

In FIG. 62, the output of the memory 54 is controlled by the output of the code detection circuit 55 to control the active / inactive state of the recording circuit 13a. The active / inactive control of the amplifier 57 may be performed. That is, the amplifier 57 is activated at the timing when the recording RF signal is output from the memory 54 (the timing at which the recording current is supplied to the recording head), and is deactivated at other times. Doing so is effective from the viewpoint of low power consumption.

Next, a modified example of FIG. 62 will be described with reference to FIG. In the embodiment of FIG. 62, the memory 54 is used for adjusting the recording timing due to the detection of the code detection circuit 55, but in the embodiment of FIG. 68, the delay line 59 is used as an analog delay element.

In this case, the recording RF signal can be subjected to analog signal processing from the input to the output of the recording circuit 13a. That is, in this embodiment, the output of the amplifier 52 is branched into two, one of which is input to the delay line 59,
The other is input to the code detection circuit 55 via the comparator 53 for binarization. And the code detection circuit 5
The output of 5 is supplied as a control signal to the amplifier 57 via the output off circuit 58. In this way, since the digital signal processing is not required in the path of the recording RF signal, the recording current can be directly controlled from outside the rotary drum, and the signal amplitude detection circuit 56 in the embodiment of FIG. 62 is unnecessary.

Since it is difficult to form the analog delay line into an IC with the current technology, it is necessary to use it as an external component of the IC. However, if a charge transfer device such as a CCD (charge coupled device) generally used as a semiconductor analog delay line is used as the delay line 59 in FIG. 68, it can be easily integrated into an IC.

Next, still another embodiment modified from FIG. 62 will be described with reference to FIGS. 69 and 70. In this embodiment, data (current code) indicating the optimum recording current value to be supplied to the recording head is inserted into the user bit in the recording RF signal, and this is detected in the recording circuit 13a to detect the recording current. I'm trying to control. Therefore, the signal amplitude detection circuit 56 in FIG.
Instead of this, a current code detection circuit 60 is provided.

User bits in the recording signal will be briefly described. FIG. 70 is a diagram showing the data structure in the audio sector, and similarly to FIGS. 65 to 67, the magazine “Broadcasting Technology” published in November 1990, November extra edition, No. 4,
Quoted from Volume 3, Issue 12. AUX0-AU in the figure
In the area X3, there is a user bit area in which the user can freely record data, and in the present embodiment, the above current is coded in this area.

The optimum value of the recording current changes depending on the gap depth of the magnetic head, but the optimum value does not change within the recording time of several hours. Therefore, it is also possible to put the current code only in the head portion of the recording data for each recording and hold the value in one recording to keep the recording current constant in one recording. With such a method, the current code is inserted only in the head portion of the recording data, so that any other data can be inserted in the user bits of AUX0 to AUX3.

Next, another basic structure of the scanner according to the present invention is shown in FIG. 71, and a concrete circuit diagram of this basic structure is shown in FIG. Similar to the case of FIGS. 1 and 2, the magnetic tape 12 is wound around the peripheral surface of the rotating drum so that the effective recording area of the information signal is 180 °. In this example, the recording circuit and the reproducing circuit are commonly connected to the rotary transformer. The recording circuit 13a amplifies the information signal from the rotary transformer 17a and drives the recording head R1.

Further, in this example, the recording head R1 has 180
A reproducing head P1 is arranged facing each other. The information signal is reproduced from the magnetic tape 12 by the reproducing head P1, amplified by the reproducing circuit 14a, and then transmitted to the outside of the rotary drum by the rotary transformer 17a connected to its output.

On the other hand, the recording circuit 13b includes a rotary transformer 17
The recording head R2 is driven by amplifying the information signal from b. A reproducing head P2 is arranged 180 ° opposite to the recording head R2, and the information signal reproduced by the reproducing head P2 is amplified by the reproducing circuit 14b commonly connected to the input of the recording circuit 14b. The rotary transformer 17b is used for transmitting an RF signal to the recording circuit 13b and transmitting an RF signal from the reproducing circuit 14b to the outside of the rotating drum.

As shown in FIG. 72, the information signal (RF signal) recorded on the magnetic tape is amplified by the rotary transformer drive circuit 15a and transmitted inside the rotary drum by the rotary transformer 17a. The recording circuit 13a is the rotary transformer 1.
7a and a reproducing circuit 14a whose inputs are commonly connected
Are sequentially switched to an active state / inactive state at every 180 ° by an R1 switching signal described later, and the recording circuit 13
When a is in the active state, the recording head R1 is driven to record the RF signal on the magnetic tape 12.

Next, reproduction of the RF signal from the magnetic tape 12 will be described. The RF signal reproduced from the magnetic tape 12 by the recording head P1 is amplified by the reproducing circuit 14a, and drives the rotary transformer 17a to which the output of the reproducing circuit 14a and the input of the recording circuit 13a are commonly connected, and then to the outside of the rotary drum. It transmits a reproduction RF signal. The reproducing circuit 14a sequentially outputs the P1 switching signal described later every 180 °.
The active transformer / inactive state is switched, and the RF signal reproduced from the reproducing head P1 in the active state is rotated by the rotary transformer 1.
It is transmitted from 7b to the outside of the rotary drum. Rotating transformer 17b
The reproduction RF signal transmitted from the receiver is received by the rotary trans-receive circuit 16a and transmitted to the subsequent circuit. On the other hand, the rotary transformer drive circuit 15b, the rotary transformer 17b,
The operation of the system of the recording circuit 13b, the reproducing circuit 14b, and the rotary trans-receive circuit 16b is similar to that described above.

The format of the output circuits of the reproduction circuits 14a and 14b and the rotary trans-receive circuits 16a and 16b is as follows.
A circuit similar to that shown in FIG. 7 may be used. However, the switching circuit of the rotary trans-receive circuits 16a and 16b adopts a switching system similar to that of the internal circuit of the rotary drum (not shown), or an FG (frequency generator) or rotary encoder for controlling the rotation of the drum. May be used to generate a switching signal, and this switching signal may be used for switching.

FIG. 73 shows a series of time sequences of the switching operation of the recording circuit and the reproducing circuit in this embodiment. The series of time sequences of the switching operation of the recording circuit including the RF detector circuit is the same as that of the circuit described above. In this case, the output of the reproducing circuit is the RF of the recording circuit.
The detector outputs the signal that detects the RF signal, but 1
Since the 80 ° switching signal is at the L level, the recording circuit does not operate during this period.

Next, after amplitude-modulating a signal for controlling the recording circuit mounted in the rotary drum so as to switch to an active / inactive state, the signal is added to the information signal to be recorded by the magnetic head. Then, the signals are transmitted by a rotary transformer together, and the signal obtained by detecting the difference in amplitude between the amplitude modulation signal and the recording RF signal is used to activate / deactivate the recording circuit.
Three embodiments of the recording circuit having a switching control function for performing inactive switching will be described.

In the first embodiment, for example, among the recording RF signals shown in the time chart of FIG. 6 showing the operation of the recording circuit of FIG. 5 and FIG. 7, the signal to be recorded by the magnetic head R1 (hereinafter, R1 recording Signal) and the magnetic head R2
Signal to be recorded by (hereinafter referred to as R2 recording signal)
A recording RF signal (hereinafter, R1 recording signal, in which a signal (hereinafter, referred to as a switching control signal) amplitude-modulated to a constant amplitude sufficiently larger than these recording signals is inserted at the beginning of each of
R2 recording signal and switching control signal are collectively referred to as recording RF.
(Referred to as a signal) for detecting a switching control signal, and a means for performing switching control based on the detected switching control signal.

In the second embodiment, the switching control signal is inserted at the beginning of the R1 recording signal, and the switching control signal is not inserted at the beginning of the R2 recording signal, and the period is switched from the recording RF signal in which there is no signal. It is an example of a recording circuit provided with a means for detecting a control signal, a means for detecting a no-signal period, and a means for performing switching control by the control signals detected by these means.

The third embodiment is a recording R in which the amplitude of the first switching control signal inserted before and after the R1 recording signal and the amplitude of the second switching control signal inserted before and after the R2 recording signal are different.
It is an example of a recording circuit including means for detecting either the first switching control signal or the second switching control signal from the F signal, and means for performing switching control by the control signal detected by this means. .

The recording circuits shown in these three embodiments are both
It also has a carrier detection function at the same time as the switching control function,
Supports insert recording. In these embodiments, like the recording circuits 13a and 13b having the configurations shown in FIGS. 1 and 2, the active / inactive state of two recording circuits arranged to face each other by 180 ° is changed to the rotation angle of the rotary drum. It is particularly effective in a VTR of a system that switches depending on the situation. Although the recording circuit is described in these three embodiments,
It is also effective in the erase circuit.

The configuration of the recording circuit in the first embodiment is shown in FIG. Further, FIGS. 75 and 76 show an operation sequence of each part of the recording circuit of FIG. 74 during normal recording and insert recording. In this embodiment, the record R
In the F signal (a), as shown in FIGS. 75 and 76, the switching control signal inserted at the beginning of each of the R1 recording signal and the R2 recording signal is larger than the amplitude of the recording signal, and the respective amplitudes are the same. FIG. 74 shows an example of the recording circuits 13a and 13b for performing control using the switching control signal detected by the signal amplitude detection means for detecting the difference in amplitude between the recording signal and the switching control signal from the recording RF signal. ing.

In FIG. 74, the recording RF signal transmitted from the rotary transformer is given to inputs 1 and 2 of the recording circuits 13a and 13b. The input recording RF signal is branched into three, the emitter follower 81 and the carrier detection circuit 8
2 and the signal amplitude detection circuit 83.

The carrier detection circuit 82 sends an H (high) level signal to the AND gate 88 while the signals including the switching control signal are being input. This carrier detection circuit 8
2 is an RF detector including a detector amplifier 22, a peak detector 23, and a comparator 24 included in the recording circuit shown in FIG.
The full-wave rectification type RF detector shown in FIGS. 2 to 22 can be used.

The signal amplitude detection circuit 83 sets the output to the H level only during the period when a signal larger than the amplitude of the recording signal by a predetermined amplitude level or more is detected, and sends this to the inverter 84 and the flip-flop 86 as a switching control signal. The signal amplitude detection circuit 83 can be realized with a circuit configuration similar to that of the carrier detection circuit by changing the signal amplitude level to be detected.

The inverter 84 sends an L (low) level signal to the AND gate 88 when the switching control signal is detected and the output of the signal amplitude detection circuit 83 is at H level. At this time AN
Since the D gate 88 outputs an L level signal to the output off circuit 89, the amplifier 90 becomes inactive and recording RF
The switching control signal included in the signal is prevented from being output as a recording current.

Since the initial setting circuit 85 resets the state of the Q output of the flip-flop 86 to L level immediately after the power is turned on, the MR of the flip-flop 86 is reset only when the power is turned on.
(Master reset) This circuit sends H level to the input.

The flip-flop 86 is a T-type flip-flop with a master reset input in this embodiment, and after the switching control signal detected by the signal amplitude detection circuit 83 is sent to the T input, the next switching control signal is sent. Is sent to the H level or L level until the
Hold on to the level. The state of the Q output is inverted every time the switching control signal is input.

EX-OR (exclusive) gate 8
7 is used to drive this recording circuit to drive the magnetic head R1.
It is a circuit for switching between the operation as a and the operation as 13b for driving the magnetic head R2. The EX-OR gate 87 sets the output to the H level when the two input levels are different, and sets the output to the L level when the two input levels match. For example, if one input is fixed to L level, the other input is L level.
When it is at the level, the output becomes the L level, and when it is at the H level, the output becomes the H level, so that the state change of the input appears in the output as it is. Further, when one input is fixed to the H level, the output becomes the H level when the other input is at the L level, and the output becomes the L level when the other input is at the H level. Appears in the output.

When the Q output of the flip-flop 86 is sent to the AND gate 88, it is possible to switch the operation of the recording circuit by utilizing this operation to switch between sending the output state as it is and inverting it. There is. When the operation switching input is fixed to the L level, the Q output of the flip-flop 86 is sent as it is, and when it is fixed to the H level, it is inverted and sent. In the former, the recording circuit operates as 13a for driving the magnetic head R1, and in the latter, 13b for the recording circuit to drive the magnetic head R2.
To work as. As a result, the operation of the recording circuit can be set so that the two recording circuits of the same structure arranged opposite to each other by 180 ° do not operate simultaneously.

The AND gate 88 is used for the carrier detection circuit 8
2. When the signals sent from the inverter 84 and the EX-OR gate 87 are all at the H level, the H level signal is sent to the output off circuit 89 to activate the amplifier 90.

The operation sequence of each part of the recording circuit of FIG. 74 during normal recording and insert recording will be described with reference to FIGS. 75 and 76.

The recording RF signal (a) transmitted from the rotary transformer is given to inputs 1 and 2 of the recording circuits 13a and 13b. The recording RF signal (a) is branched into three and input to the emitter follower 81, the carrier detection circuit 82 and the signal amplitude detection circuit 83. The output (b) of the carrier detection circuit 82 is at the H level while the signals including the switching control signal are being input. Output of signal amplitude detection circuit 83 (c)
Becomes H level only during the period when the switching control signal is detected.
The output (c) of the signal amplitude detection circuit 83 is inverted by the inverter 84 and becomes an inverted output of the signal amplitude detection circuit (c '). Therefore, the AND gate 88 is provided while the switching control signal is detected.
The switching signals (e1, e2), which is the output of, are set to the L level. Since the output off circuit 89 makes the amplifier 90 inactive during this period, the switching control signal included in the recording RF signal is not output as the recording current.

The Q output of the flip-flop 86 of the signal amplitude detection circuit 83 is detected by detecting the first switching control signal from the state where it is reset to the L level by the initialization circuit, that is, the switching control signal at the head of the R1 recording signal. When the output (c) changes to the H level, it changes to the H level, the second switching control signal, that is, the switching control signal at the head of the R2 recording signal is detected, and the output (c) of the signal amplitude detection circuit 83 is changed again. When it reaches the H level, it changes to the L level.
Similarly thereafter, the Q output of the flip-flop 86 is inverted every time the switching control signal is detected.

In the case of the recording circuit 13a, since the output (d1) of the EX-OR gate 87 is the Q output of the flip-flop 86 as it is, it becomes H level when the odd-numbered switching control signal is detected, and the even-numbered switching control signal. When the switching control signal is detected, it becomes L level. The switching signal (e1) is output when the inputs of the AND gate 88 are all at the H level, that is, the output (b) of the carrier detection circuit 82, the inverted output of the signal amplitude detection circuit (c '), and the output of the EX-OR gate 87 ( When all of d1) become H level, it becomes H level. Since the output OR circuit 89 activates the amplifier 90 when the switching signal (e1) is at the H level, the recording current corresponding to the R1 recording signal is output as shown by the R1 recording current (f1), and the R2 recording signal is output. The corresponding recording current is not output.

In the case of the recording circuit 13b, the output (d2) of the EX-OR gate 87 appears by inverting the Q output of the flip-flop 86. Therefore, when the odd-numbered switching control signal is detected, it becomes L level and even. It goes high when the second switching control signal is detected. The switching signal (e2) is output when the inputs of the AND gate 88 are all at the H level, that is, the output of the carrier detection circuit 82 (b), the inverted output of the signal amplitude detection circuit (c '), and the output of the EX-OR gate 87 ( When all of d2) become H level, it becomes H level. Since the output OR circuit 89 activates the amplifier 90 when the switching signal (e2) is at the H level, the recording current corresponding to the R1 recording signal is not output as indicated by the R2 recording current (f2), and the R2 recording signal is not output. The recording current corresponding to is output.

Similarly, at the time of insert recording, switching of the recording circuits 13a and 13b is controlled by the switching control signal added to the head of the R1 recording signal and the R2 recording signal, and only the signal to be insert-recorded is recorded by the carrier detection circuit. By doing so, partial rewriting becomes possible.

Also in this embodiment, the same effect as in the previous embodiment can be obtained. This embodiment is the LE shown in FIG.
It is possible to switch the recording circuits 13a and 13b without using the recording circuit control means by the D column and the photodetector. Further, since it is not necessary to provide a dedicated rotary transformer or a channel such as a slip ring for transmitting the switching control signal, it is possible to perform normal recording and partial rewriting of only the video track and partial rewriting of the audio track while maintaining the VTR. The circuit configuration of the recording system is simple and miniaturized.

The structure of the recording circuit in the second embodiment is shown in FIG. 78 and 74 show the operation sequences of the respective parts of the recording circuit of FIG. 77 during normal recording and insert recording.

In this embodiment, the recording RF signal (a)
78 and 79, the switching control signal is inserted at the beginning of the R1 recording signal, the switching control signal is not inserted at the beginning of the R2 recording signal, and there is no signal period between the R1 recording signal and the R2 recording signal. Is provided. The switching control signal is detected by the signal amplitude detecting means similar to that of the first embodiment and becomes the first switching control signal. The no-signal period of the recording RF signal is detected by the carrier detecting means and becomes the second switching control signal.
The present embodiment is an example of a recording circuit that performs switching control using these two switching control signals.

In this embodiment, the first shown in FIG.
2 is different from that of the first embodiment in that an RS flip-flop is used as the flip-flop 86, and the first switching control signal from the signal amplitude detection circuit 83 and the output signal of the carrier detection circuit 82 are inverted by the inverter 91 to perform the second switching. The flip-flop 86 is controlled by the control signal, and the adoption of this control method eliminates the need for the initialization circuit. The other circuits are the same as those of the embodiment shown in FIG. 74, and the description thereof will be omitted.

In FIG. 77, when the recording RF signal is in a non-signal state, the output of the carrier detection circuit 82 becomes L level and the output of the inverter 91 which is the second switching control signal is inverted and becomes H level.

A signal of H level is sent from the inverter 91 to the R input of the flip-flop 86, and the Q output of the flip-flop 86 is reset to L level. The state of the Q output of the flip-flop 86 is maintained until the output of the signal amplitude detection circuit 83, which is the first switching control signal, becomes H level and is sent to the S input. When an H level signal is sent to the S input, the Q output state of the flip-flop 86 is set to the H level. The state of the Q output of the flip-flop 86 is maintained until the carrier detection circuit 82 detects the no-signal state, sets the output of the inverter 91, which is the second switching control signal, to the H level, and is sent to the R input. .

The Q output of the flip-flop 86 is recorded R
Since the F signal is always reset to the L level when there is no signal, the initialization circuit used in the recording circuit shown in the first embodiment of FIG. 74 becomes unnecessary. The following circuit operation is the same as that of the first embodiment.

The operation sequence of each part of the recording circuit of FIG. 77 during normal recording and insert recording will be described with reference to FIGS. 78 and 79.

The recording RF signal (a) transmitted from the rotary transformer is given to inputs 1 and 2 of the recording circuits 13a and 13b. The recording RF signal (a) is branched into three and input to the emitter follower 81, the carrier detection circuit 82 and the signal amplitude detection circuit 83.

The output (b) of the carrier detection circuit 82 is at H level before and after the recording RF signal is sent, and the R1 recording signal and R
The 2 signal non-signal period is at the L level. The output (b) of the carrier detection circuit 82 is inverted by the inverter 91 and becomes the carrier detection circuit inverted output (b ').

The output (c) of the signal amplitude detection circuit 83 becomes H level only during the period when the switching control signal is detected. The circuit output (c) of the signal amplitude detection circuit 83 is inverted by the inverter 84 and inverted by the signal amplitude detection circuit (c ').
Therefore, while the switching control signal is being detected, AND
The switching signals (e1, e2) output from the gate 88 are set to L level. During this period, the output off circuit 89 is operated by the amplifier 90.
Is made inactive, the switching control signal included in the recording RF signal is not output as a recording current.

The Q output of the flip-flop 86 is the recording R
The first switching control signal, that is, the switching control signal at the beginning of the R1 recording signal is detected from the initial state in which the F signal is not sent and is reset, and the output (c) of the signal amplitude detection circuit 83 becomes the H level. Sometimes set to H level,
When the no-signal period at the head of the R2 recording signal is detected and the carrier detection circuit inverted output (b ') becomes H level, it is reset to L level. Similarly thereafter, the output Q of the flip-flop 86 is alternately set / reset and inverted by the output (c) of the signal amplitude detection circuit 83 and the inverted output (b ') of the carrier detection circuit.

In the case of the recording circuit 13a, the output (d1) of the EX-OR gate 87 is the Q output of the flip-flop 86 as it is. When the no-signal period at the beginning of the R2 recording signal is detected, it becomes L level. The switching signal (e1) is output when the inputs of the AND gate 88 are all at the H level, that is, the output (b) of the carrier detection circuit 82, the inverted output (e ') of the signal amplitude detection circuit, and the output (d1) of the EX-OR gate 87. When all of () become H level, they become H level. The output off circuit 89 activates the amplifier 90 when the switching signal (e1) is at the H level, so that the R1 recording signal current (f1) indicates R1.
The recording current corresponding to the recording signal is output, but the recording current corresponding to the R2 recording signal is not output.

In the case of the recording circuit 13b, the output (d2) of the EX-OR gate circuit 87 appears by inverting the Q output of the flip-flop 86. Therefore, when the switching control signal at the head of the R1 recording signal is detected, L is output. It becomes the level, and becomes the H level when the no-signal period at the head of the R2 recording signal is detected. The switching signal (e2) is output when the inputs of the AND gate 88 are all at the H level, that is, the output (b) of the carrier detection circuit 82, the inverted output of the signal amplitude detection circuit (e '), and the output of the EX-OR gate 87 ( When all of d2) become H level, it becomes H level. Since the output off circuit 89 activates the amplifier 90 when the switching signal (e2) is at the H level, the recording current corresponding to the R1 recording signal is not output as shown by the R2 recording current (f2).
A recording current corresponding to the R2 recording signal is output.

Similarly, at the time of insert recording, the first switching control signal added to the beginning of the R1 recording signal and the second switching control signal detecting the no-signal period at the beginning of the R2 recording signal cause the recording circuit 13a, By controlling the switching of 13b and recording only the signal to be insert-recorded by the carrier detection circuit 82, partial rewriting becomes possible. Also in this embodiment, the same effect as in the previous embodiment can be obtained.

The configuration of the recording circuit in the third embodiment is shown in FIG. Further, FIG. 51 and FIG. 52 show operation sequences of respective parts of the recording circuit of FIG. 50 at the time of normal recording and insert recording.

In this embodiment, recording RF signal (a)
As shown in FIGS. 51 and 52, the amplitude of the first switching control signal (hereinafter, referred to as R1 switching control signal) inserted before and after the R1 recording signal is the second insertion before and after the R2 recording signal.
Is larger than the amplitude of the switching control signal (hereinafter, referred to as R2 switching control signal). In the present embodiment, one of the switching control signals is detected depending on the difference in amplitude between the R1 switching control signal and the R2 switching control signal.
The recording circuit 13b is an example of a recording circuit that detects a switching control signal to switch active / inactive, and the recording circuit 13b detects an R2 switching control signal and switches active / inactive.

The recording RF signal transmitted from the rotary transformer is given to inputs 1 and 2 of the recording circuits 13a and 13b. The input recording RF signal is branched into two, one to the emitter follower 81 and the other to the signal amplitude detection circuit 83.
Entered in.

The function of the signal amplitude detection circuit 83 in this embodiment is different from that of the first and second embodiments, and the functions of the recording signal, R1 switching control signal and R2 switching control signal included in the recording RF signal are different. To detect the difference in amplitude, set the upper and lower limits of the comparison reference, output an H level signal when the signal amplitude level is within this range, and output an L level signal if it exceeds this range. Output. For example, in the case of the recording RF signal (a) in FIG. 51, if the upper limit larger than the amplitude of the R1 switching control signal is set and the lower limit larger than the amplitude of the R2 switching control signal is set, the R1 switching control signal is detected. Further, if an upper limit larger than the amplitude of the R2 switching control signal smaller than the amplitude of the R1 switching control signal is set and a lower limit larger than the amplitude of the recording signal is set, the R2 switching control signal is detected.

The detection level setting input is fixed to a certain appropriate potential, and by changing this potential, it is set which of the R1 switching control signal and the R2 switching control signal is to be detected. The recording circuit for detecting the former operates as 13a, and the recording circuit for detecting the latter operates as 13b.
As a result, the two recording circuits of the same structure arranged opposite to each other by 180 ° do not operate at the same time, and the EX-OR gate 87 used in the previous embodiment becomes unnecessary.

Further, in this embodiment, the recording circuit 13a records only the R1 recording signal sandwiched between the R1 switching control signals, and the recording circuit 13b records the R2 recording signal sandwiched between the R2 switching control signals.
Since only the recording signal is recorded, it is not necessary to control using the carrier detection circuit in order to output only the signal to be recorded.

The inverter 84, the initialization circuit 85 and the flip-flop 86 have the same structure as the recording circuit shown in the first embodiment and have the same functions.

Unlike the first and second embodiments, the AND gate 88 has two inputs because the carrier detection circuit is eliminated. The AND gate 88 is the inverter 8
4. When the signals sent from the flip-flop 86 are both at the H level, the H level signal is sent to the output off circuit 89 to activate the amplifier 90.

The operation sequence of each part of the recording circuit of FIG. 50 during normal recording and insert recording will be described with reference to FIGS. 51 and 52.

The recording RF signal (a) transmitted from the rotary transformer is given to inputs 1 and 2 of the recording circuits 13a and 13b. The recording RF signal (a) is branched into two and input to the emitter follower 81 and the signal amplitude detection circuit 83.

In the case of the recording circuit 13a, the output (c1) of the signal amplitude detection circuit 83 becomes H level when the R1 switching control signal is detected. The output of the signal amplitude detection circuit 83 (c
1) is inverted by the inverter 84 and becomes the signal amplitude detection circuit inverted output (e1 '). Therefore, while the R1 switching control signal is being detected, the switching signal (e1) output from the AND gate 88 is set to the L level. To do. During this period, the output off circuit 89 makes the amplifier 90 inactive, so that the switching control signal included in the recording RF signal is not output as the recording current.

When the switching control signal at the head of the R1 recording signal is detected while the Q output (d1) of the flip-flop 86 has already been reset to the L level, the Q output (d1) goes to the H level and is output to the end of the R1 recording signal. A certain level of switching control signal is detected and goes to the l level. Since the R2 switching control signal is not detected, there is no change in the Q output. Similarly thereafter, the Q output of the flip-flop 86 is inverted every time the R1 switching control signal is detected.

The switching signal (e1) becomes all H levels when the inputs of the AND gate 88 all become H level, that is, the inverted output of the signal amplitude detection circuit (e1 ') and the output (d1) of the flip-flop 86. When it goes high, it goes high. Since the output off circuit 89 activates the amplifier 90 when the switching signal (e1) is at the H level, the recording current corresponding to the R1 recording signal is output as shown by the R1 recording current (f1), and the R2 recording signal is output. The recording current corresponding to is not output.

In the case of the recording circuit 13b, the output (c2) of the signal amplitude detection circuit 83 becomes H level when the R2 switching control signal is detected. The output (c2) of the signal amplitude detection circuit 83 is inverted by the inverter 84 to become the signal amplitude detection circuit inverted output (e2 '). Therefore, while the R2 switching control signal is detected, the output of the AND gate 88 is switched. The signal (e2) is set to L level. During this period, the output off circuit 89 makes the amplifier 90 inactive, so that the recording R
The switching control signal included in the F signal is not output as the recording current.

Q output of flip-flop 86 (d2)
Becomes H level when the switching control signal at the head of the R2 recording signal is detected while it has already been reset to L level, and becomes L level at which the switching control signal at the end of the R2 recording signal is detected. . Since the R1 switching control signal is not detected, there is no change in the Q output. Similarly thereafter, the Q output of the flip-flop 86 is inverted every time the R2 switching control signal is detected.

The switching signal (e2) becomes high when all the inputs of the AND gate 88 become high, that is, the inverted output of the signal amplitude detection circuit (e2 ') and the output (d2) of the flip-flop 86 become high. When it goes high, it goes high. Since the output off circuit 89 activates the amplifier 90 when the switching signal (e2) is at the H level, the recording current corresponding to the R1 recording signal is not output as indicated by the R2 recording current (f2), and the R2 recording is performed. A recording current corresponding to the signal is output.

Similarly, at the time of insert recording, the recording circuit 13
Each of a and 13b controls the switching by the switching control signal added before and after the recording signal to be insert-recorded, and records only the signal sandwiched between the respective switching control signals, whereby partial rewriting becomes possible. Also in this embodiment, the same effects as those of the previous two embodiments can be obtained.

Next, an example of a specific configuration of the signal amplitude detection circuit 83 in the third embodiment will be described with reference to the configuration diagram of FIG. 83 and the operation sequence of FIG.

The recorded RF signal (a) is output to the signal amplitude detection circuit 8
After the input of 3, the rectifier circuit 92 and the low-pass filter 9
The amplitude level of the recorded RF signal is detected after passing 3 and 2
The amplitude level detection signal (x) is sent to the two comparators 94 and 95.

The comparator 94 outputs an H level signal when the input signal is smaller than the threshold voltage V1 and outputs an L level when the input signal exceeds V1. The comparator 95 outputs an L level signal when the input signal is lower than the threshold voltage V2, and outputs an H level signal when the input signal exceeds V2.

The AND gate 96 includes comparators 94 and 9
When both outputs are at H level, H level signal is output and becomes R1 switching control signal or R2 switching control signal.

The threshold voltages V _T1 and V _T2 of the comparators 94 and 95 are divided by the three resistors Z1, Z2 and Z3 and set to a predetermined potential. By controlling the threshold voltages V _T1 and V _T2 with the potential applied to the detection level setting input, only one of the R1 switching control signal and the R2 switching control signal can be selected and detected.

As shown in the amplitude level detection signal (x) of FIG. 84, when detecting the R1 switching control signal, the threshold voltage V _T1 is set to V1 larger than the amplitude of the R1 switching control signal and the threshold voltage V _T1 is set to V1. V _T2 is smaller than the amplitude of the R1 switching control signal and is larger than the amplitude of the recording signal V 2
Set to. At this time, the recording circuit operates as 13a.

When detecting the R2 switching control signal,
The threshold voltage V _T1 is set to V1 ′ smaller than the amplitude of the R1 switching control signal and larger than the amplitude of the R2 switching control signal, and the threshold voltage V _T2 is set to V2 ′ smaller than the amplitude of the R2 switching control signal and larger than the recording signal amplitude. To do. At this time, it operates as the recording circuit 13b.

In the case of the recording circuit 13a, since the threshold voltage V _T1 is set to V1, the comparator output (y1) is always at the H level, and the threshold voltage V _{T1
Since T2} is set to V2, the comparator output (z
In 1), it becomes H level only while the R1 switching control signal is input.

The signal amplitude detection circuit output (e1) which is the output of the AND gate 96 becomes H level when both the comparator output (y1) and the comparator output (z1) are H level.

In the case of the recording circuit 13b, since the threshold voltage V _T1 is set to V1 ', the comparator output (y2) is at the L level only while the R1 switching control signal is being input, and the threshold voltage V _T2 is Since it is set to V2 ', the comparator output (z2) is R1
It is at the H level only while the switching control signal and the R2 switching control signal are being input.

The signal amplitude detection circuit output (e2) which is the output of the AND gate 96 becomes the H level when both the comparator output (y2) and the comparator output (z2) are at the H level, so the R1 switching control signal is input. During the period, the output becomes L level according to the comparator output (y2),
It becomes H level only while the R2 switching control signal is being input.

This signal amplitude detecting circuit is a circuit to which the RF detector shown in FIG. 12 is applied, and two comparators 94 and 95 detect only a signal having an amplitude within a certain range. This signal amplitude detection circuit is R
The same effect as described in the embodiment of the F detector is obtained.

In the recording circuits of the embodiments shown in FIGS. 74, 77 and 80, a switching control signal having an amplitude sufficiently larger than that of the recording signal is added, but there is a difference in amplitude between the recording signal and the switching control signal. The same control can be performed even if a switching control signal having an amplitude smaller than the recording signal is added, as long as it can be detected.

As for the logic circuits such as the inverters, AND gates, EX-OR gates and flip-flops used in these embodiments, other kinds of logic circuits are used as long as the same control is possible as a result. You may.

The recording circuit of the embodiment shown in FIGS. 74 and 77 has a built-in initialization circuit. However, the recording circuit is provided with only an input terminal for initialization and is initialized via a slip ring. You may go. In this case, since a plurality of recording circuits may be initialized at the same time, the number of slip rings may be increased by one channel. Further, since the recording circuits of these embodiments can be integrated into an IC, it is easy to mount them in the rotary drum.

Next, an embodiment in which the tape-head contact detecting means is used to control the active / inactive state of at least the output stage of at least one of the recording circuit, the reproducing circuit and the erasing circuit of the drum mounting circuit will be described. To do. Since this embodiment is the same as the previous embodiment except that the control is performed by using the tape-head contact detecting means, only the points different from the previous embodiment will be described.

FIG. 85 is a circuit diagram showing the configuration of the inside of the scanner in the embodiment, in which the piezoelectric elements 18a, 18b and 19a, 19b are provided in the vicinity of the recording heads R1 and R2 and the reproducing heads P1 and P2, respectively. The recording circuits 13a and 13b and the reproduction circuits 14a and 1 are provided.
4b in that they are respectively connected to 4b.

The piezoelectric element 18a detects the period during which the recording head R1 is in contact with the magnetic tape (the period during which it passes through the recording area), and controls the recording circuit 13a. That is, the piezoelectric element 18b, which keeps the output stage of the recording circuit 13a in the active state only during the period when the recording head R1 is passing through the recording area and keeps the output stage in the inactive state during the other period, similarly operates the recording circuit 13b. Control.

The piezoelectric element 19a detects the period during which the reproducing head P1 is in contact with the magnetic tape (the period during which it passes through the recording area), and controls the reproducing circuit 14a. That is, the output stage of the reproducing circuit 14a is activated only during the period when the reproducing head P1 is passing through the recording area, and the output stage is deactivated during the other period. The piezoelectric element 19b similarly controls the reproducing circuit 14b.

In this way, the recording circuits 13a, 13b and the reproducing circuits 14a, 14b are switched between active / inactive states at every 180 °, and control that is completely the same as 180 ° switching by the conventional LED array and photodetector can be realized. .

Two specific examples of the structure of the head assembly including the magnetic head and the piezoelectric element for detecting the contact period between the magnetic head and the magnetic tape in this embodiment will be described with reference to FIGS. 86 and 87. Explain.

FIG. 86 (a) is a view of the head assembly seen from above, and FIG. 86 (b) is a sectional view seen from the side. This head assembly has a structure in which a piezoelectric element 202 is inserted between a head base 201 that is fixed to a rotating drum (not shown) and a head chip 203 that actually has a recording or reproducing function. It is arranged on a straight line connecting the center of rotation of the drum and the head chip 203.

A centrifugal force acts on the head assembly composed of the head base 201, the piezoelectric element 202 and the head chip 203 as the rotary drum rotates.
When the head chip 203 comes into contact with a magnetic tape (not shown) wound around the rotary drum, the head chip 203 is pushed back by a force in the direction opposite to the centrifugal force, so that pressure is applied to the piezoelectric element 202. The piezoelectric element 202 converts this pressure into an electric signal and generates a switching signal for the recording circuit or the reproducing circuit.

FIG. 87 (a) is a view of the head assembly as viewed from above, and FIG. 87 (b) is a view of the front surface (the surface in contact with the magnetic tape). In this example, the head chip 20
3 and the piezoelectric element 202 are arranged along the traveling direction of the head assembly, and the head chip 203 is arranged so as to precede the piezoelectric element 202 in the traveling direction. The piezoelectric element 20 includes the head base 201 and the head chip 203.
In order to sandwich 2 between them, a projection is provided at the end of the head base 201 at the end opposite to the direction of travel of the head assembly.

A force acts on the head assembly in the traveling direction of the head assembly together with the centrifugal force due to the rotation of the rotary drum. When the head chip 203 comes into contact with the magnetic tape, a frictional force exerts a force on the head chip 203 in a direction opposite to the traveling direction of the head assembly, and a pressure is applied to the piezoelectric element 202. The piezoelectric element 202 converts this pressure into an electric signal and generates a switching signal for the recording circuit or the reproducing circuit. In this way, the contact between the magnetic head and the magnetic tape can be detected.

In the example of FIGS. 86 and 87, the piezoelectric element 2 sandwiched between the head base 201 and the head chip 203.
Although the contact between the magnetic head and the magnetic tape was detected by the change in the pressure applied to 02, for example, by sandwiching the piezoelectric element between the head base and the rotary drum to which it is fixed, the above-mentioned 2
The contact between the magnetic head and the magnetic tape may be detected in the same manner as in the first example.

Next, the recording circuit 13 in this embodiment.
A and 13b will be described with reference to FIG. 88. The recording circuits 13a and 13b have a built-in switching function for controlling the switching of the output stage between the active state and the inactive state by the R1 switching signal and the R2 switching signal generated by the piezoelectric elements 18a and 18b, respectively.

In FIG. 88, the recording RF signal transmitted from the rotary transformer is given to the input 1 and the input 2 of the recording circuit 13a. This recorded RF signal passes through the emitter follower 301 and is input to the amplifier 305.

On the other hand, the R1 switching signal generated by the piezoelectric element 18a is given to the switching signal input of the recording circuit 13a, amplified by the amplifier 302, and then binarized by the comparator 303. The comparator 303 sends an H level signal to the output off circuit 304 while the recording head R1 is in contact with the magnetic tape. At this time, the output off circuit 304 activates the amplifier 305 to supply the recording current corresponding to the recording RF signal to the recording head R1. The recording circuit 13b operates similarly.

If the amplitude level of the electric signal generated by the piezoelectric element is sufficiently large, the amplifier 302 in FIG. 88 may be omitted and the comparator 303 may directly perform binarization.

Next, the reproducing circuit 14 in this embodiment.
A and 14b will be described with reference to FIG. 89. The reproducing circuits 14a and 14b have a built-in switching function for controlling the switching of the output stage between the active state and the inactive state according to the P1 switching signal and the P2 switching signal generated by the piezoelectric elements 19a and 19b.

The RF signal reproduced by the reproducing head P1 is given to the input 1 and the input 2 of the reproducing circuit 14a. The reproduced RF signal passes through the head amplifier 306 and is input to the amplifier 310.

On the other hand, the P1 switching signal generated by the piezoelectric element 19a is given to the switching signal input of the reproducing circuit 14a, amplified by the amplifier 307, and then binarized by the comparator 308. The comparator 308 is the reproducing head P
Output off circuit 3 while 1 is in contact with the magnetic tape
The H (high) level signal is sent to 09. At this time, the output-off circuit 309 activates the amplifier 310 to turn on the reproduction RF.
The signal is transmitted to the outside of the rotary drum by the rotary transformer. The reproducing circuit 14b operates in the same manner.

If the amplitude level of the electric signal generated by the piezoelectric element is sufficiently large, the amplifier 307 in FIG. 89 may be omitted and the comparator 308 may directly perform binarization.

Next, an embodiment of the method for manufacturing the rotary transformer device used in the present invention will be described with reference to FIGS. As a rotary transformer, a coaxial rotary transformer in which a magnetic core is magnetically separated for each channel is known in order to reduce channel-to-channel variation and crosstalk, which are particularly problematic in a wideband, high transmission rate VTR such as an HDTV VTR. ing. This coaxial type rotary transformer coaxially connects a rotating side element and a fixed side element, which are composed of a magnetic core of a plurality of channels magnetically separated for each channel and a winding attached to each magnetic core for each channel. Of the magnetic cores of the rotating side element and the fixed side element, the magnetic cores on which the windings are mounted on the inner peripheral side of the magnetic cores arranged and configured include a first core having a winding groove and a second core having no winding groove. Cores are alternately arranged in the axial direction.

According to the present invention, in the manufacture of such a coaxial rotary transformer device, the first core has the annular concave groove serving as the winding groove on the surface orthogonal to the axial direction as the first core. Material, a flat plate annular second as the second core
Core materials are prepared, the winding is inserted into the annular groove, and the first and second core materials are alternately laminated including the short rings when using the short rings. And a step of polishing the inner peripheral surfaces of the laminated first and second core materials until the winding is exposed.

FIG. 93 is a cross-sectional view showing a magnetic core in which windings are mounted on the inner peripheral side of the magnetic cores of the rotating side element and the fixed side element in this embodiment and the windings thereof, and before performing the polishing. Shows the state of. On the other hand, FIG. 94 is a cross-sectional view after the above polishing, and this FIG. 94 is a magnetic core in which windings are mounted on the inner peripheral side of a coaxial type rotary transformer device simultaneously manufactured by the conventional manufacturing method. And its windings.

In FIGS. 93 and 94, reference numeral 900 denotes a hollow magnetic core made of a soft magnetic material such as ferrite, which has a first core 901 having a winding groove 902 and a second core not having a winding groove. 903 are laminated by alternately arranging them in the axial direction via short rings 904. In this way, the magnetic core 900 is separated into the first core 901 and the second core 903 in order to easily install the winding from the inside, which is generally difficult. The short ring 904 is for magnetically separating the magnetic core 900 for each channel. A winding 905 such as an enameled wire is installed in the winding groove 902. The entire magnetic core 900 is housed in a cylindrical housing 906 made of non-magnetic metal such as aluminum.

A lead wire is actually provided on the winding wire 905, and the lead wire is drawn to the outside through a lead wire groove or the like provided on the magnetic core 900 or the housing 906, but it is omitted in the drawing.

FIG. 95 is a perspective view showing the manufacturing process of this embodiment, and FIG. 96 is a perspective view showing the conventional manufacturing process. Traditionally,
First, as the first core 901, a core having a step 910 to be a winding groove 902 as shown in FIG. 96A is prepared,
On this step 910, as shown in FIG. 96 (b), the winding 9
Install 05. In this case, as shown in FIG. 96 (c), a part 905 ′ of the winding wire 905 may project inward from above the step 910 and be separated from the core 901. In order to prevent this, the winding 905 is carefully wound over time, a special jig is used, or a winding having a stable shape, for example, a copper plate ring processed by etching or the like is used. However, there is a drawback that the manufacturing cost increases in any case.

On the other hand, in the present invention, FIG. 93 and FIG.
As shown in FIG. 5 (a), as the first core 901, an annular groove 907 serving as a winding groove 902 is provided on a surface orthogonal to the axial direction by providing a thick portion 908 on the innermost peripheral portion. The formed first core material is prepared. Then, the winding 905 is inserted into the annular groove 907 as shown in FIGS. 93 and 95 (b). In this case, the winding 905 has a thick portion 90.
Since it is regulated by No. 8, it can be stably installed without a part of it protruding inward and coming off from the core 901 as shown in FIG. 96 (c).

On the other hand, the second core 903 shown in FIG.
(A) Prepare a flat plate annular second core material having substantially the same inner diameter as the inner diameter of the first core material 901 shown in (b), and further provide a short ring having substantially the same inner diameter as this. Is prepared and the first core material after inserting the winding wire 905 into the annular groove 907, the second core material and the short ring are laminated as shown in FIG. It is accommodated in the housing 906. In this state, the opening of the annular groove 907 of the first core material is closed by the second core material, so that an annular closed space is formed between the first core material and the second core material. The winding 90 is placed in the annular closed space.
5 will be held stably.

Next, the inner peripheral surfaces of the first and second core materials and the short ring are polished by a lathe or the like to the position indicated by the broken line in FIG. In this state after the inner peripheral sides of the first and second core materials and the short ring have been polished, focusing on the shape of the first core material, as shown in FIG.
By scraping off the thick portion 908 of (a) and (b), the inner peripheral side of the closed space is opened and the winding 905 is exposed. As a result, the overall shape of the magnetic core 900 is shown in FIG.
As shown in FIG. 5, a coaxial rotary transformer device having the same structure as that manufactured by the conventional manufacturing method can be obtained.

As described above, according to the method of manufacturing the rotary transformer device of the present invention, the windings can be easily installed, the yield can be improved, and the manufacturing cost can be reduced.

Although the four-channel rotary transformer device is shown in the above embodiment, the number of channels is not limited to this. Further, in the above embodiment, an example in which the windings of two circuits are installed in one winding groove is shown, but the present invention can be applied to a rotary transformer device in which windings of multiple circuits are installed.

Next, an embodiment of the mounting method of the scanner unit according to the present invention will be described with reference to FIGS. 97 to 99. FIG. 97 is a view for explaining the structure and manufacturing process of the reproduction circuit board unit in the scanner section. First, (a)
As shown in FIG.
Chip components of passive elements such as 1002, resistor 1003, and capacitor 1004 are automatically mounted. On the other hand, in parallel with this, as shown in FIG.
The photodetector bare chip 1006 is mounted on the substrate 5 and wired on the substrate 1005 by the bonding wire 1007, and after the operation check, the one sealed with the transparent resin 1008 as shown in (c) is prepared. And (c)
By fixing the photodetector substrate 1005 of (a) onto the reproduction circuit substrate 1001 of (a) with an adhesive 1009,
Hybrid IC with playback circuit and photodetector integrated
Thus, a regenerated circuit board unit is obtained.

The photodetector bare chip 1006 may be sealed with the transparent resin 1008 after the photodetector substrate 1005 is fixed on the reproduction circuit substrate 1001 and then attached.

FIG. 98 shows another embodiment of the reproducing circuit board unit, in which the photodetector bare chip 1006 is directly mounted on the reproducing circuit board 1001 without using the photodetector board as in FIG.

In FIG. 99, the reproducing circuit board 1001 is mounted on the lower part of the rotary drum 3, the recording circuit board 2001 is mounted on the upper part, and the ICs of the recording circuits 13a and 13b are mounted on the lower surface of the recording circuit board 2001 to reproduce the reproducing circuit. Board 100
The ICs of the reproduction circuits 14a and 14b are mounted on the lower surface of the No. 1 unit. The recording photodetectors 5a and 5b are mounted on the upper surface of the recording circuit board 2001, and the reproducing photodetectors 6a and 6b are mounted on the lower surface of the reproducing circuit board 1001. Photodetectors 5a, 5b, 6a, 6
Similarly to FIG. 98, b is a photodetector bare chip sealed with a transparent resin.

On the other hand, the upper fixed drum 4a and the lower fixed drum 4b are arranged above and below the rotary drum 3, respectively, and the LED substrate 20 provided on these fixed drums 4a and 4b.
10, 1010 on the photo detectors 5a, 5 for recording.
The recording LED row 7 and the reproducing LED row 8 are arranged so as to face the b and the reproducing photodetectors 6a and 6b. The LED substrates 201 and 1010 are provided with grooves or through holes as in FIG. 12, and the LED rows 7 and 8 are provided in these grooves or through holes, respectively.

Here, conventionally, the reproducing photodetectors (6a, 6b) are mounted on the recording circuit board 2001 together with the recording photodetectors 5a, 5b as shown by the broken line in FIG. 99, and the reproducing photodetectors (6a, 6b) are reproduced on the upper fixed drum 4a. Since the LED array (8) is mounted so as to face the reproduction photodetectors (6a, 6b), the same number of photodetectors as the reproduction heads are used to connect the reproduction photodetectors on the recording circuit board 2001 onto the reproduction circuit board 1001. Since a lead wire for transmitting a control signal from the scanner is required, increasing the number of heads is one of the causes for increasing the labor and cost required for manufacturing the scanner.

On the other hand, as in the embodiment of FIG. 99, the reproducing photodetector is moved onto the reproducing circuit board 1001 and the reproducing LED array is moved to the lower fixed drum 4b in accordance with this, whereby a reproducing photodetector is formed. It is not necessary to arrange lead wires for connecting the reproduction circuit board 1001, which is extremely convenient in manufacturing.

The present invention is not limited to the above-described embodiments, but can be modified in various ways as follows.

For example, in the above embodiment, the case of the rotary drum type VTR has been described, but the present invention can be applied to a VTR adopting another magnetic head mounting system such as a disk type or a medium drum type. is there.

In the above embodiment, the case of switching the 1-channel rotary transformer and the 2-channel recording circuit or the reproducing circuit has been described. However, when switching the multi-channel recording circuit and / or the reproducing circuit, or a circuit for performing both of them. The present invention can be implemented in the same manner.
For example, the recording head and the recording circuit are 8 channels, the reproducing head and the reproducing circuit are 8 channels, and the effective recording area angle is 180.
In the case of °, the rotary transformer may have 8 channels.

Further, in the above-mentioned embodiment, the system using the LED array has been described as the control system of the drum mounting circuit, but the recording circuit, the reproducing circuit and the erasing circuit mounted on the rotary drum are limited to the common control system. Not a thing.
The three control methods of the drum mounting circuit proposed in Japanese Patent Application No. 1-127911 may adopt different control methods depending on each circuit. For example, the recording circuit and the erasing circuit may be controlled by an LED array, and the reproducing circuit may be a method using a photoreflector.

Furthermore, it is possible to adopt the same active / inactive control system as that of the recording circuit for the erasing circuit. During insert editing, the erase circuit always operates when the recording circuit operates. Therefore, if the tape format permits, the control of the erasing circuit can be such that the recording LED row is also used as the erasing LED row. In this case, the full erase head is normally used during normal recording, but at this time, unless the erase RF signal is transmitted to the erase circuit in the rotary drum, the above-mentioned RF detector does not operate, so the erase circuit is activated. It won't end up.

[0305]

As described above, according to the present invention, a control means for controlling the active / inactive state of the output stage of a plurality of recording circuits is added to the recording circuit, thereby controlling the drum mounting circuit. It will be very easy.

For example, the light emitting element array and the light receiving element array are used as the first detection means for detecting the period in which each of the plurality of recording heads is in contact with the magnetic tape, and the rotary drum is provided in each recording circuit. A second detecting means for detecting an information signal to be recorded transmitted from the outside is provided, and the first detecting means is provided.
Of the recording circuit detects that the recording head corresponding to the recording circuit is in contact with the magnetic tape, and the second detecting unit detects the information signal, the output stage of the recording circuit is activated. According to the configuration, only the recording light emitting element array is prepared as the light emitting element array for controlling the drum mounting circuit, and the normal recording and the partial rewriting of only the video track and the audio track can be performed. Further, since the number of elements in the light emitting element array is reduced, it is possible to achieve low power consumption and cost reduction.

On the other hand, an amplitude modulation signal which is added to the information signal to be recorded, which is transmitted from the outside of the rotary drum, to each recording circuit according to the rotational position of the rotary drum, and which is amplitude-modulated to have an amplitude different from that of the information signal. Or a detecting means for detecting a unique code added to the information signal is provided in each recording circuit, and at least the output stage of the recording circuit is provided only during the period when the predetermined code is detected. If the LED is set to the active state, normal recording and partial rewriting of only the video track and audio track can be performed without using the LED array, and the LED
Since it is not necessary to transmit a control signal for 180 ° switching by rows, photodetectors, slip rings, rotating drums, or optical transmission, reliability is improved and peripheral circuits are not complicated.

Further, according to the present invention, the plurality of reproducing circuits are provided with the control means for activating the reproducing circuits only during the period when the information signal reproduced by the reproducing head is detected. With respect to the control of the active state, the control by the LED array or the like is not necessary, so that the power consumption can be reduced and the cost can be reduced.

Further, according to the present invention, the magnetic tape and the magnetic head are brought into contact with each other by the tape-head contact detection means provided in at least one of the recording circuit, the reproducing circuit and the erasing circuit of the drum mounting circuit. The circuit is configured such that at least the output stage of the circuit is activated only during the period when it is detected that the control signal generated inside the rotary drum is used without using the LED string.
° Control such as switching becomes possible, and the control circuit for that becomes simple. This facilitates the assembly of the scanner and the maintenance of the drum-mounted circuit, which leads to cost reduction, downsizing of the scanner, and downsizing of the entire VTR device.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a scanner unit in a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a circuit diagram more specifically showing the main part of FIG.

FIG. 3 is a diagram showing a series of time sequences of the switching operation of the recording / reproducing circuit in the embodiment.

FIG. 4 is a diagram showing an example of a reproducing circuit in which an output has a high impedance in a non-active state.

FIG. 5 is a block diagram showing a configuration example of a recording circuit having a carrier detection function according to the present invention.

FIG. 6 is a time chart showing the operation of the recording circuit of FIG. 5 during normal recording.

7 is a time chart showing the operation of the recording circuit of FIG. 5 during insert recording.

FIG. 8 is a circuit diagram showing in detail a main part of the recording circuit of FIG.

FIG. 9 is a diagram showing a light emitting direction of an LED bare chip.

FIG. 10 is a diagram showing a light intensity distribution of an LED bare chip.

FIG. 11 is a diagram showing a mounting structure of an LED array.

FIG. 12 is a diagram showing a mounting structure of an LED array.

FIG. 13 is a diagram showing a mounting structure of an LED array.

FIG. 14 is a diagram showing a mounting structure of an LED array.

FIG. 15 is a diagram showing a mounting structure of an LED array.

FIG. 16 is a diagram showing a mounting structure of an LED array.

FIG. 17 is a diagram showing a mounting structure of an LED array.

FIG. 18 is a perspective view of an annular cylindrical lens portion in FIG.

FIG. 19 is an enlarged view of a part of FIG.

FIG. 20 is a diagram showing a conventional cylindrical lens.

FIG. 21 is a diagram showing a mounting structure of an LED array.

FIG. 22 is a wiring diagram of LED rows

FIG. 23 is a wiring diagram of an LED row.

FIG. 24 is a wiring diagram of LED rows

FIG. 25: Wiring diagram of LED row

FIG. 26 is a wiring diagram of LED rows

FIG. 27 is a wiring diagram of the LED row

FIG. 28 is a block diagram of a VTR recording / reproducing system to which the present invention is applied.

FIG. 29 shows the configuration of a conventional VTR recording / reproducing system.
Block diagram shown in comparison with 8

FIG. 30 is a block diagram showing an embodiment in which a photodetector and circuits associated therewith are integrated with a recording circuit having a carrier detection function according to the present invention.

FIG. 31 is a diagram showing a mounting structure of a photo detector in the example.

FIG. 32 is a view showing another mounting structure of the photo detector in the example.

FIG. 33 is a cross-sectional view showing the configuration of the scanner section in the example.

FIG. 34 is a diagram showing an internal structure of a package to which the MCP method is applied.

FIG. 35 is a diagram showing another embodiment of the scanner unit in the present invention.

FIG. 36 is a configuration diagram of a photodetector and circuits associated therewith in the embodiment.

FIG. 37 is a diagram showing an operation sequence of the embodiment.

FIG. 38 is a diagram showing another embodiment of the scanner unit in the present invention.

FIG. 39 is a diagram showing details of the reflective photosensor in FIG. 38.

FIG. 40 is a sectional view showing an example in which a reflective photo sensor and a recording circuit are mounted on the same hybrid IC.

FIG. 41 is a block diagram showing another configuration example of a recording circuit having a carrier detection function according to the present invention.

42 is a block diagram showing a configuration example of the full-wave rectification type RF detector in FIG. 41.

FIG. 43 is a diagram showing operation waveforms of respective parts of FIG. 42.

FIG. 44 is a block diagram showing a configuration example of the full-wave rectification type RF detector in FIG. 41.

FIG. 45 is a diagram showing operation waveforms of respective parts of FIG. 44.

FIG. 46 is a block diagram showing a configuration example of the full-wave rectification type RF detector in FIG. 41.

FIG. 47 is a diagram showing operation waveforms of respective parts in FIG. 46.

48 is a block diagram showing a configuration example of the full-wave rectification type RF detector in FIG. 41.

FIG. 49 is a diagram showing operation waveforms of respective parts of FIG. 48 with respect to a sinusoidal RF signal.

FIG. 50 is a diagram showing operation waveforms of respective parts of FIG. 48 with respect to a square-wave RF signal.

51 is a block diagram showing a configuration example of the full-wave rectification type RF detector in FIG. 41.

52 is a diagram showing operation waveforms of respective parts of FIG. 51.

FIG. 53 is a block diagram showing a configuration example of a recording circuit having a recording circuit designation code detection function according to the present invention.

54 is a time chart showing the operation of the recording circuit of FIG. 53 during normal recording.

FIG. 55 is a time chart showing the operation of the recording circuit of FIG. 53 during insert recording.

FIG. 56 is a block diagram showing another configuration example of a recording circuit having a recording circuit designation code detecting function according to the present invention.

FIG. 57 is a block diagram showing a configuration example of a reproducing circuit having a carrier detecting function according to the present invention.

58 is a time chart showing the operation of the reproducing circuit of FIG. 57 during normal reproduction.

FIG. 59 is a block diagram showing another configuration example of a reproducing circuit having a carrier detecting function according to the present invention.

FIG. 60 is a time chart showing the operation of the reproducing circuit of FIG. 57 during special reproduction.

61 is a time chart showing the operation of the reproduction circuit of FIG. 59 during special reproduction.

FIG. 62 is a block diagram showing a configuration example of a recording circuit having a number code detecting function according to the present invention.

FIG. 63 is a time chart showing the operation of the recording circuit of FIG. 62 during normal recording.

64 is a time chart showing the operation of the recording circuit of FIG. 62 during insert recording.

FIG. 65 is a diagram showing a data structure in a helical track in the D-2 format.

FIG. 66 is a diagram showing a sync block ID format in the D-2 format.

FIG. 67 is a diagram showing sync block ID numbers in the D-2 format.

68 is a block diagram showing another configuration example of the recording circuit having the number code detecting function according to the present invention. FIG.

FIG. 69 is a block diagram showing another configuration example of the recording circuit having the number code detection function according to the present invention.

FIG. 70 is a diagram showing a data structure in an audio sector in the D-2 format.

FIG. 71 is a schematic configuration diagram of a scanner unit in a magnetic recording / reproducing apparatus according to another embodiment of the present invention.

72 is a circuit diagram more specifically showing the main part of FIG. 71. FIG.

FIG. 73 is a view showing a series of time sequences of the switching operation of the recording / reproducing circuit in the example.

FIG. 74 is a block diagram showing a configuration example of a recording circuit having a 180 ° switching control function according to the present invention.

FIG. 75 is a time chart showing the operation of the recording circuit of FIG. 74 during normal recording.

FIG. 76 is a time chart showing the operation of the recording circuit of FIG. 74 during insert recording.

FIG. 77 is a block diagram showing a configuration example of a recording circuit having a 180 ° switching control function according to the present invention.

78 is a time chart showing the operation of the recording circuit of FIG. 77 during normal recording.

79 is a time chart showing the operation of the recording circuit of FIG. 77 during insert recording.

FIG. 80 is a block diagram showing a configuration example of a recording circuit having a 180 ° switching control function according to the present invention.

81 is a time chart showing the operation of the recording circuit of FIG. 80 during normal recording.

82 is a time chart showing the operation of the recording circuit of FIG. 77 during insert recording.

83 is a block diagram showing a configuration example of the signal amplitude detection circuit in FIG. 80.

84 is a time chart showing the operation of the signal amplitude detection circuit of FIG. 83.

FIG. 85 is a circuit diagram showing a configuration of a main part in the scanner in the embodiment in which the drum-mounted circuit is controlled by using the tape-head contact detection means.

FIG. 86 is a view showing an example of a magnetic head assembly having a tape-head contact detection function according to the present invention.

FIG. 87 is a view showing another example of a magnetic head assembly having a tape-head contact detection function according to the present invention.

88 is a block diagram showing a configuration example of a recording circuit in the example. FIG.

FIG. 89 is a block diagram showing a configuration example of a reproducing circuit in the example.

FIG. 90 is a sectional view of a drum system showing a basic configuration of a conventional 180 ° switching system.

FIG. 91 is a diagram showing a footprint of the D2 format.

FIG. 92 is a view showing a conventional drum-mounted circuit control LED array compatible with a D2 format footprint.

FIG. 93 is a cross-sectional view for explaining the method of manufacturing the coaxial rotary transformer device according to the present invention.

FIG. 94 is a cross-sectional view of the coaxial rotary transformer device.

FIG. 95 is a perspective view for explaining a manufacturing process of the coaxial rotary transformer device according to the present invention.

FIG. 96 is a perspective view for explaining a manufacturing process of a conventional coaxial rotary transformer device.

FIG. 97 is a view for explaining the structure and manufacturing process of the reproduction circuit board unit of the scanner unit according to the present invention.

FIG. 98 is a view showing another example of the reproduction circuit board unit.

FIG. 99 is a cross-sectional view showing a mounting structure of a recording circuit board unit, a reproducing circuit board unit, a recording LED array, a recording photo detector, and a reproducing LED array and a reproducing photo detector in the scanner of the present invention.

[Explanation of symbols]

1 ... Scanner 2 ... Magnetic Tape 3 ... Rotating Drum 4 ... Fixed Drum 5 (5a, 5b) ... Recording Photo Detector 6 (6a, 6b) ... Reproducing Photo Detector 7 ... Recording LED Row 8 ... Reproducing LE
Row D 11 (R1, R2) ... Recording head 12 (P1, P
2) ... reproducing heads 13a, 13b ... recording circuits 14a, 14b
Reproducing circuit 15 Revolving transformer drive circuit 16 Revolving drum receiving circuit 18a, 18b Piezoelectric element 19a, 19b
... Piezoelectric element 21 ... Emitter follower 22 ... Detector amplifier 23 ... Peak detector 24 ... Comparator 25 ... AND gate 26 ... Output off circuit 27 ... Amplifiers 28, 28a,
28b ... Full wave rectifier circuit 29 ... Low pass filter 30 ... High pass filter 31 ... Emitter follower 32 ... Code detection amplifier 33 ... Comparator 35 ... Output off circuit 36 ... Amplifier 37 ... Carrier detection circuit 41 ... Head amplifier 42 ... Detector amplifier 43 ... Peak Detector 44 ... Comparator 45 ... Output off circuit 46 ... Amplifier 51 ... Emitter follower 52 ... Amplifier 53 ... Comparator 54 ... Memory 55 ... Code detection circuit 56 ... Signal amplitude detection circuit 57 ... Amplifier 58 ... Output off circuit 59 ... Delay line 60 ... Current code detection circuit 70 ... Limiter amplifier 71 ... Delay circuit 72 ... OR gate 81 ... Emitter follower 82 ... Carrier detection circuit 83 ... Signal amplitude detection circuit 85 ... Initialization circuit 89 ... Output off circuit 90 ... Amplifier 92 ... All Wave rectifier circuit 93 ... Low-pass filter 94, 95 ... Comparator 201 ... Head base 202 ... Piezoelectric element 203 ... Head chip

Claims (15)

[Claims] 1. A rotating drum, and a plurality of recording heads and reproducing heads mounted on the rotating drum and contacting and running on a magnetic tape wound around the peripheral surface of the rotating drum to record / reproduce information signals. A plurality of recording circuits mounted in the rotary drum and connected to the recording heads; and first detecting means for detecting a period during which each of the recording heads is in contact with the magnetic tape. And second detecting means provided in each of the plurality of recording circuits for detecting information signals to be recorded transmitted from the outside of the rotary drum to the recording circuits, and in each of the plurality of recording circuits. The first detecting means detects that the recording head corresponding to the recording circuit is in contact with the magnetic tape, and the second detecting means detects the information signal. Rotary scanning type magnetic recording and reproducing apparatus characterized by comprising a control means for the active state the output stage only the recording circuit period but detected. 2. The first detecting means is provided on an end surface of a fixed drum, which is arranged so as to face the rotary drum, facing the rotary drum, and extends over a predetermined angle range along the rotation direction of the rotary drum. A plurality of light emitting element rows arranged in an annular shape, and a plurality of light receiving elements provided at a position corresponding to each of the recording heads on an end surface of the rotating drum facing the fixed drum, 2. The rotary scanning magnetic recording / reproducing apparatus according to claim 1, wherein the light receiving element outputs a signal indicating a period during which each of the recording heads is in contact with the magnetic tape. 3. The light emitting element array is provided in a groove or a hole formed in an annular shape over a predetermined angle range along a rotation direction of the rotary drum on an end surface of the fixed drum facing the rotary drum. The rotary scanning magnetic recording / reproducing apparatus according to claim 2, wherein the magnetic recording / reproducing apparatus is arranged. 4. The rotary scanning type magnetic device according to claim 2, wherein the light emitting element arrays are connected in series every predetermined number in the arrangement direction, and each series circuit is connected to a power source. Recording / playback device. 5. The rotary scanning magnetic recording / reproducing apparatus according to claim 2, wherein the light receiving element is mounted on the same hybrid integrated circuit together with the recording circuit. 6. A rotating drum, and a plurality of recording heads and reproducing heads mounted on the rotating drum and contacting and running on a magnetic tape wound around the peripheral surface of the rotating drum to record / reproduce information signals. A plurality of recording circuits mounted in the rotary drum and connected to the recording head respectively; and a plurality of recording circuits respectively provided in the plurality of recording circuits, which are transmitted to the recording circuits from outside the rotary drum. First detection means for detecting an amplitude-modulated signal that is added to an incoming information signal to be recorded according to the rotational position of the rotary drum and is amplitude-modulated to have an amplitude different from that of the information signal; Second detecting means provided in each of the plurality of recording circuits for detecting an information signal to be recorded transmitted to the recording circuit from the outside of the rotary drum. The output stage of the recording circuit is activated only during the period in which the first detection means detects the amplitude-modulated signal having a predetermined amplitude and the second detection means detects the information signal. A rotary scanning magnetic recording / reproducing apparatus comprising: a control unit. 7. The second detecting means includes at least one full-wave rectifying circuit for full-wave rectifying the information signal, and binarizing means for converting an output signal of the full-wave rectifying circuit into a binary signal. , Delay means for delaying the binary signal output from this means,
7. A rotary scanning type magnetic recording / reproducing device according to claim 1, further comprising a logical sum circuit for calculating a logical sum of the signal delayed by the means and the binary signal output from the binarizing means. apparatus. 8. The second detecting means includes at least one stage full-wave rectifying circuit for full-wave rectifying the information signal, and binarizing means for converting an output signal of the full-wave rectifying circuit into a binary signal. , Delay means for delaying the binary signal output from this means,
7. A rotary scanning type magnetic recording / reproducing device according to claim 1, further comprising a logical sum circuit for calculating a logical sum of the signal delayed by the means and the binary signal output from the binarizing means. apparatus. 9. A rotating drum, and a plurality of recording heads and reproducing heads mounted on the rotating drum and contacting and running on a magnetic tape wound around the peripheral surface of the rotating drum to record / reproduce information signals. A plurality of recording circuits mounted in the rotating drum and connected to the recording head respectively; and a plurality of recording circuits respectively provided in the plurality of recording circuits, which are transmitted to the recording circuits from outside the rotating drum. Detecting means for detecting a recording circuit designating code added to an incoming information signal to be recorded, and the recording circuit designating code provided in each of the plurality of recording circuits and detected by the detecting means is set in the recording circuit. And a control means for bringing the output stage of the recording circuit into an active state only for a period corresponding to the generated unique code. Place 10. A rotating drum, and a plurality of recording heads and reproducing heads mounted on the rotating drum and contacting and running on a magnetic tape wound around the peripheral surface of the rotating drum to record / reproduce information signals. A plurality of recording circuits mounted in the rotating drum and connected to the recording head respectively; and a plurality of recording circuits respectively provided in the plurality of recording circuits, which are transmitted to the recording circuits from outside the rotating drum. Detecting means for detecting a code representing at least one of a sync block number in a sync block or a track number, a segment number and a field number in a sector ID added to an incoming information signal to be recorded; Provided in each of the recording circuits, and the code detected by the detecting means is unique to the recording circuit. And a control means for setting the output stage of the recording circuit to an active state only for a period corresponding to the code. 11. A rotary drum, and a plurality of magnetic heads mounted on the rotary drum, which come into contact with a running magnetic tape wound around a peripheral surface of the rotary drum to record, reproduce and erase information signals. A plurality of drum mounting circuits mounted in the rotary drum and including a recording circuit, a reproducing circuit and an erasing circuit respectively connected to the plurality of magnetic heads, and arranged in proximity to each of the magnetic heads, A tape-head contact detecting means for detecting whether or not the magnetic tape and the magnetic head are in contact with each other, and at least one of a recording circuit, a reproducing circuit and an erasing circuit of the plurality of drum-mounted circuits. Each of the recording times is provided only during a period when the tape-head contact detecting means detects that the magnetic tape and the magnetic head are in contact with each other. And a control means for activating at least an output stage of at least one of a path, a reproducing circuit and an erasing circuit. 12. A rotating drum, and a plurality of recording heads and reproducing heads mounted on the rotating drum and contacting and running on a magnetic tape wound around the peripheral surface of the rotating drum to record / reproduce information signals. A plurality of reproducing circuits mounted in the rotary drum and connected to the reproducing head, and a detection circuit provided in each of the reproducing circuits for detecting an information signal reproduced by the reproducing head. And a control means which is provided in each of the plurality of reproduction circuits and which activates an output stage of the reproduction circuit only during a period when an information signal is detected by the detection means. Type magnetic recording / reproducing apparatus. 13. The detecting means includes at least one stage full-wave rectifier circuit for full-wave rectifying the information signal, a low-pass filter for removing high-frequency components from an output signal of the full-wave rectifier circuit, and a low-pass filter for the low-pass filter. 7. The rotary scanning type magnetic recording / reproducing apparatus according to claim 6, further comprising a binarizing means for converting the output signal into a binary signal. 14. The detecting means includes at least one full-wave rectifying circuit for full-wave rectifying the information signal, a binarizing means for converting an output signal of the full-wave rectifying circuit into a binary signal, and the means. And a logical sum circuit for logically summing the signal delayed by the means and the binary signal output from the binarizing means. The rotary scanning magnetic recording / reproducing apparatus according to claim 12. 15. A rotating-side element and a fixed-side element, each of which is composed of a magnetic core of a plurality of channels magnetically separated for each channel and a winding mounted on the magnetic core for each channel, are coaxially arranged. A magnetic core of the rotating side element and the fixed side element, in which the winding is mounted on the inner peripheral side, includes a first core having a winding groove and a second core having no winding groove. In a method of manufacturing a coaxial type rotary transformer device in which cores are alternately arranged in the axial direction, a ring-shaped concave groove serving as the winding groove is formed on a surface orthogonal to the axial direction as the first core. A first core material and a flat plate annular second core material are respectively prepared as the second core, and after the winding is inserted into the annular groove, the first and second cores are formed. Materials are alternately laminated, and the laminated first and second core materials A method of manufacturing a rotary transformer device, comprising a step of polishing an inner peripheral surface until the winding is exposed.