JPH077545B2 - Recording / playback device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a rotary head type digital audio tape recorder (hereinafter referred to as DAT), and particularly to a tape running speed and a cylinder rotation speed in a high speed search such as music selection. The present invention relates to a recording / reproducing device having a control device.

[Conventional technology]

As a method of controlling the relative speed of the tape and the head attached to the cylinder to be constant by changing the rotation speed of the cylinder according to the running speed of the tape, for example, Japanese Patent Laid-Open No. 61-214164, 61-110359. It is described in the official gazette. In the above publication, a signal recorded on a tape is reproduced, a clock is extracted from the reproduced signal, and a cylinder rotation speed is controlled by controlling a cylinder rotation speed so that a clock frequency becomes constant. The relative speed was controlled to be constant.

[Problems to be solved by the invention]

However, in the above-mentioned conventional technique, no consideration is given to a control method in the case of shifting from an area in which no signal is recorded on the tape and data and clock cannot be reproduced to an area in which a signal is recorded.

An object of the present invention is to provide a search control system capable of reliably reproducing a recording signal when the non-signal area is transferred to the signal recording area.

[Means for solving problems]

The purpose of the above is to increase the running speed of the tape while discriminating the presence / absence of a recording signal on the tape. When there is no recording signal on the tape, the relative speed of the tape and the head is higher than the original relative speed. This is achieved by setting the cylinder rotation speed so that it becomes higher and shifting to the recording signal area.

[Action]

In the area where the signal is recorded on the tape, the recording signal detection means determines that there is a recording signal, the head reproduces the digital signal on the tape, and the clock is reproduced from the reproduced signal. The voltage converting means converts the voltage into a voltage and applies the output voltage to the rotary head driving motor to control the rotational speed of the rotary head so that the relative speed between the rotary head and the tape speed becomes a constant value. On the other hand, when the operation is started in the area where the signal is not recorded on the tape, the recording signal detection means determines that there is no recording signal, and the relative speed of the rotary head with respect to the tape traveling speed is less than the above constant value. The rotation speed of the rotary head is controlled by the rotation control means so as to be higher. As a result, when the signal enters the area where the signal is recorded next time, the relative speed of the tape and the head is high, so that the signal level reproduced from the differential characteristic of the head becomes high, and the recorded signal can be reliably reproduced.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. In the figure, 1 is a cylinder, 2A and 2B are magnetic heads, 3
Is a tape, 4,5 is a reproduction amplifier, 6 is a switching circuit for switching the magnetic head outputs of 2A and 2B, 7 is an envelope detector of a reproduction signal, 8 is a recording signal detector, and 9 is a waveform equalization of the reproduction signal. An equalizer to perform, 10 a comparator, 11 a PLL that reproduces a data cycle clock from reproduced data, 12
Is a frequency voltage converter (F-V converter), 13 is a cylinder drive motor, 14 is a cylinder motor FG (frequency generator), 15 is an F-V converter, 16 is a switching circuit, and 17 and 18 are tapes. Is a reel for feeding and winding the tape, 19 and 20 are reel FGs, 21 is a reel drive motor, 22 is a tape speed control circuit, and 23 is a head switching signal generation circuit.

As described above, in the embodiment of FIG. 1, when controlling the tape running so that the relative speed between the head and the tape is constant, in the area where no signal is recorded on the tape, The cylinder speed is controlled so that the relative speed becomes higher than the constant relative speed. The operation of each part will be described below with reference to specific examples and operation waveforms.

The magnetic heads 2A and 2B attached to the rotary cylinder 1 are
The recording signal is reproduced from the tape 3, and the reproduction amplifiers 4 and 5 amplify the signal read by the head. Switching circuit 6
Selects a reproduction amplifier output for reproducing the head output on the side in contact with the tape according to the output of the head switching signal generation circuit 23. The selected signal is waveform-equalized by the equalizer 9 and binarized by the comparator 10 to generate a PL signal.
Sent to L11. The PLL regenerates a clock synchronized with the data from the binarized data. Here, the frequency of the reproduced clock is proportional to the relative speed of the tape and the head. That is, when the relative speed of the head with respect to the running speed of the tape is higher than the original speed, the frequency of the reproduction clock becomes higher than the frequency corresponding to the transmission rate, and vice versa. Therefore, in the area where the signal is recorded on the tape, the frequency of the reproduction clock is set to F− so that the frequency of the reproduction clock is always constant.
By converting the voltage into a voltage by the V converter 12 and controlling the rotation speed of the cylinder with this voltage, the relative speed between the tape and the head can be controlled to be constant.

On the other hand, the clock cannot be reproduced in the area where the signal is not recorded on the tape. Therefore, in the non-signal area, the tape running speed and the relative speed difference between the head and the head cannot be detected, so that the cylinder speed cannot be controlled and the relative speed deviates. When the relative speed deviates in the small direction, the reproduction signal level is lowered and the clock cannot be reproduced even in the area where the signal is recorded because the characteristic of the magnetic head is the differential characteristic. Therefore, the output of the magnetic head switching circuit 6 is detected by the envelope detector 7, the recording signal detector 8 determines the presence / absence of the envelope, and when there is no recording signal, the FV converter 15 controls the output. The cylinder rotational speed is selected to be larger than the original relative speed to the tape running speed, and the recording signal is waited for. That is, the reel speed control circuit 22 drives the reel motor 21 while measuring the frequencies of the reels FG 19, 20 to rotate the reels 17, 18 to run the tape. At the same time, reel speed control circuit 22
Sends the tape speed and tape running direction to the recording signal detector. In the recording signal detector 8, the recording signal is “present”
In this case, the switching circuit 16 is connected to the side a, and the cylinder rotation speed is controlled by a control voltage obtained by FV of the reproduction clock of the PLL so that the relative speed of the tape and the head is controlled to be constant. On the other hand, when the recording signal is "none", the switching circuit 16 is connected to the side b and the tape speed control circuit 22
FV converter based on tape speed and direction information
Set the center frequency of 15 so that the relative speed is high,
FV converter 15 with FG14 of cylinder motor as input signal
The rotation speed is controlled by.

As described above, when there is no recording signal on the tape, the relative speed of the head is made higher than the constant value of the original relative speed with respect to the running speed of the tape, and then the area where the recording signal is present is reproduced. However, even if the signal level is not lowered, the signal can be surely reproduced and the constant relative speed can be controlled.

Next, the control timing of the present invention will be described with reference to FIGS.
It will be described with reference to the drawings.

FIG. 2 is a timing chart when the tape is running at a high speed. (1) is the tape speed, (2) is the reproduction signal, (3) is the recording signal detector output, and (4) is the cylinder rotation. Indicates a number. In (1), υ ₀ is the running speed of the tape before the tape speed change, and it is 0 when the tape is stopped,
υ ₁ is the final target value for high-speed driving speed. or,
N _{0 in} (4) is the rotation speed of the cylinder with respect to the tape speed υ ₀ , and is 0 or the rotation speed with respect to υ ₀ when the tape is stopped. The broken line in (4) is the rotation speed at which the relative speed of the tape and head becomes constant when the tape speed changes from υ ₀ to υ ₁ , and N ₁ is the rotation speed at which the relative speed is constant relative to the tape speed υ ₁ . Is a number.
When there is no recording signal at the time of tape start, the recording signal detector output becomes "L", and it is determined that there is no recording signal. Further, the recording signal detector determines the rotation speed N _{1 of the} cylinder from the information of the tape running direction and the final target value sent from the tape speed control circuit, and sets the center rotation speed of the FV converter 15 to N. ₁ + ΔN, the switching circuit 16 is switched to the b side, and the cylinder speed is set to N ₁ + ΔN. In this state, the recording signal area is waited for, and when the signal comes out, control is performed at a constant relative speed based on the reproduction clock.

FIG. 3 is a timing chart showing another method of setting the rotation speed. In FIG. 3, the tape speed control circuit controls the tape speed and at the same time sends the tape speed information to the recording signal detector. The recording signal detector 8 determines the number of rotations N at a constant relative speed based on the tape speed information, and sets the center frequency of the FV converter 15 to N +.
ΔN is set, the switching circuit 16 is switched to the b side, and the cylinder speed is set to N + ΔN. In this state, the recording signal area is waited for, and when the signal comes out, control is performed at a constant relative speed based on the reproduction clock.

FIG. 4 is a timing diagram showing another method. Fourth
In the figure, if there is no recording signal after the tape is started, or if the recording signal does not appear even after the elapse of a certain time T, the information of the tape speed control circuit is used as in the embodiment of FIG. And set the cylinder speed to N ₁ + ΔN,
It waits until the area with the recording signal comes out. When a recording signal comes out in this state, control is performed at a constant relative speed based on the reproduction clock.

FIG. 5 is a timing diagram showing another method. Fifth
In the figure, after the tape starts, until the tape speed reaches the target speed υ ₁ , the cylinder speed N ₀ is held even if there is no recording signal, and even if the tape speed reaches the target speed υ ₁ , the recording signal is If there is no record signal, the cylinder speed is set to N ₁ + ΔN based on the information from the tape speed control circuit when the recording signal is detected, and the process waits until an area with a recording signal appears. In this state, when a recording signal comes out, control is performed at a constant relative speed based on the reproduction clock.

As described above, according to the present embodiment, when there is no recording signal on the tape, the relative speed of the head with respect to the tape speed is set higher than the original relative speed to reproduce the area with the next recording signal. Even if the signal level is not lowered, the signal can be surely reproduced and the constant relative speed can be controlled.

Next, a configuration example of the recording signal detector of the present invention will be described.

FIG. 6 shows an example of the recording signal detection method.

The method of FIG. 6 is a method of counting the number of envelopes of a reproduction signal with one head and determining that there is a recording signal when the envelope is above a certain threshold value. FIG. 7 shows an example of realization of this system. In FIG.
The components having the same numbers as those in the figure indicate the same components.
Reference numeral 24 is a reference voltage, 25 is a comparator, 26 is a counting circuit, 27 is a register, and 28 is a cylinder rotation speed target value setting circuit. The output A of the envelope detector 7 is compared with the reference voltage 24 by the comparator 25 and binarized. The counting circuit 26 counts the number of pulses from the output of the comparator between the edge of the head switching signal and the next edge, and when the threshold value is exceeded, the information indicating the recording signal is registered. Then, the register captures the information at the switching edge of the head switching signal. By this register output D, the switching circuit 16 shown in FIG.
Control. In addition, the information C from the tape speed control circuit 22 is input, and the cylinder circuit number target value setting circuit 28
Determines the center frequency by the FV converter 15, and the control signal E
To send. As described above, according to the present embodiment, the presence / absence of the recording signal on the tape can be determined. Further, in the present embodiment, it was detected how many envelopes were reproduced by each head.
It is possible to detect how many envelopes are present in both heads B or in how many revolutions. That is, if the counting operation is performed using only the rising edge or only the falling edge, the determination is made once per rotation (both A and B heads).

Next, another embodiment of the recording signal detector will be described.

FIG. 8 shows another example of the recording signal detection method. In this method, the time width of the envelope is measured with one head, and when a pulse having a time width equal to or larger than a certain threshold is detected, it is determined that there is a recording signal. Figure 9 shows
It shows one implementation example of this system, and the components having the same numbers as in FIG. 7 indicate the same components. 29 is an oscillator and 30 is a counting circuit. The output of the envelope detector is binarized by the comparator, and when the output is "L", the counter circuit is cleared. The counting circuit counts the clock input from the oscillator 29 when the clear input is “H”. When the count value of the counting circuit exceeds a certain threshold value, it is determined that the time width of the envelope exceeds the threshold value, and it is determined that there is a recording signal. The register rewrites this determination information at the switching edge of the head switching signal, and the switching circuit 16
The control signal D of is output. The cylinder rotation speed target value setting circuit is similar to that of the embodiment shown in FIG.

As described above, according to this embodiment, it is possible to determine the presence / absence of the recording signal on the tape. Further, similarly to the embodiment shown in FIG. 7, the detection may be performed with both the A and B heads or a cycle of several revolutions.

Next, another example of the recording signal detection method will be described.

FIG. 10 shows another example of the recording signal detection method. This method is a method of determining that there is a recording signal when an envelope having a time width of a certain threshold value or more is present between the edges of the head switching signal and a certain threshold value or more.

FIG. 11 shows an implementation example of the method of FIG. In FIG. 11, the components having the same numbers as those in FIG. 9 represent the same components, and 31 is a counting circuit. Counting circuit 30
Then, a pulse having a time width equal to or larger than the threshold value is detected, and the number of times of detection is counted by the counting circuit 31 several times. When this count value is greater than or equal to the threshold value, it is determined that there is a recording signal on the tape.

As described above, according to this embodiment, the presence / absence of the recording signal on the tape can be determined. Further, similarly to the embodiment shown in FIG. 7, the detection may be performed with both A and B heads or a cycle of several revolutions.

FIG. 12 shows an example in which detection is performed at a cycle of one rotation (both A and B heads).

Next, another configuration example of the recording signal detector of the present invention will be described with reference to FIGS.

In FIG. 13, the components having the same numbers as those in FIG. 9 indicate the same components. Also, 101, 106, 108, 110 are capacity, 102, 103, 10
5,107,111,112,113 are resistors, 109 is a voltage source, and 114 is an amplifier. Further, FIG. 14 shows operation waveforms of the respective parts in FIG.

In FIG. 13, the input F of the envelope detector 7 is
The reproduced waveform of the recording signal as shown in FIG. 14F is input. In the envelope detector 7, the direct current is cut off by the capacitor 101, the direct current operating point of the transistor 104 is determined by the resistors 102 and 103, the envelope of the reproduction signal F is detected by the transistor 104, the resistor 105 and the capacitor 106, and the resistor 107 and the capacitor 108 are detected. Output through a low pass leaky wave. The output G of the envelope detector 7 outputs the envelope of the reproduction signal as shown in G of FIG. 14, but with respect to the reference voltage Vr,
A deviation occurs by the DC level ΔV.

In the recording signal detector, an envelope signal whose DC level is deviated with respect to the reference voltage Vr is input. Therefore, in order to detect the envelope, the slice level of the comparator for detecting the envelope should be at the center of the envelope. There is a need.

A magnetic head such as a DAT recorder is placed 180 ° away from the cylinder and the tape is wound 90 ° around the cylinder to record and reproduce the signal. As shown in Fig. 14F, the reproduced signal is the time when the cylinder rotates 90 °. A signal is output and there is no signal for the remaining 90 °. Therefore, when the signal of FIG. 14G is passed through the capacitor 110 of FIG. 13, the output signal of the envelope detector is, as shown in FIG. 14H, that the reference voltage Vr is at a DC level that crosses the envelope. Is shifted. This signal is amplified by the amplifier 114 and binarized by the comparator 25 to obtain the envelope comparator output I. Based on this signal, as described in detail in the above embodiment, the recording signal is obtained. It is possible to determine whether or not there is.

As described above, according to the present embodiment, even if the output DC level of the envelope detector fluctuates, the envelope signal can be accurately binarized, and the presence or absence of the recording signal can be determined.

Next, another embodiment of the present invention will be described. FIG. 15 shows an embodiment of the present invention, in which the components having the same numbers as those in FIG. 1 represent the same components, 29 is a PLL lock state discriminator, and 30 is a sweep voltage generator. A circuit, 31 is a switching circuit. Further, FIG. 16 shows the timing of this embodiment. F-V conversion of the reproduction clock,
The control operation for keeping the cylinder rotation speed constant is the same as that described in the above embodiment, and therefore will be omitted.

The present embodiment describes the control in the case where the locked state of the PLL is released and the recording signal subsequently disappears during the constant relative speed control.

If the PLL comes out of the locked state during the control operation with a constant relative speed, it becomes impossible to detect the relative speed deviation, so that the control operation comes off. Therefore, in order to return to the constant relative speed control again, it is necessary to forcibly swing the cylinder rotation speed up and down to search for the rotation speed at which the PLL locks.

In this operation (hereinafter referred to as sweep operation), when the PLL lock state determiner 29 detects that the PLL is out of the lock state, the switching circuit 31 is controlled and the sweep voltage generation circuit 30 controls the cylinder rotation speed. Shake it up and down. This sweep operation may return to constant relative speed control immediately if the number of cylinder rotations at which the PLL locks is found once, or it may change to constant relative speed control after repeating the sweep operation several times. It may return. However, when the recording signal disappears during this sweep operation, or when the recording signal comes next, if the cylinder rotation speed is low, the signal may not be detected. Therefore, according to the present invention, the presence or absence of the recording signal is detected even during the sweep operation, and when the recording signal disappears, the control is performed so that the cylinder speed becomes the relative speed as in the above embodiment. Thus, when the recording signal comes out again, it is possible to reliably reproduce the signal and return to the constant relative speed control without failing to detect the signal.

The embodiments of the present invention have been described above.
With both a device equipped with both recording and playback functions and a device with only a playback function for playing back prerecorded tapes,
It is obvious that it can be applied during the reproduction.

〔The invention's effect〕

As described above, according to the present invention, in the area where the signal is not recorded on the tape, the relative speed between the tape and the magnetic head is increased, and when the next area where the signal is recorded, the signal is reliably recorded. It is possible to reproduce and to perform constant relative speed control.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a diagram showing a control method of the present invention, FIG. 3 is a diagram showing another control method of the present invention, and FIG. FIG. 5 is a diagram showing another control method of the present invention, FIG. 5 is a diagram showing still another control method of the present invention, FIG. 6 is a diagram showing a recording signal detection method of the present invention, and FIG. FIG. 8 is a block diagram of an implementation example of a recording signal detection method of the present invention, FIG. 8 is a diagram showing another recording signal detection method of the present invention, and FIG. 9 is an implementation example of another recording signal detection method of the present invention. FIG. 10, FIG. 10 is a diagram showing another recording signal detection method of the present invention, FIG. 11 is a block diagram of an example of realization of another recording signal detection method of the present invention, and FIG. FIG. 13 is a diagram showing still another recording signal detecting method of the invention, FIG. 13 is a block diagram of an embodiment of the invention, and FIG. 14 is a diagram of an embodiment of the invention. Timing diagram, FIG. 15 is a block diagram of another embodiment of the present invention, FIG. 16 is an operation waveform diagram of each part of another embodiment of the present invention. 7 ... Envelope detector, 8 ... Recording signal detector 16 ... Switching circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shozaburo Sakaguchi 25 Nishi-machi, Yamada, Kawagoe City, Saitama Prefecture 1 Pioneer Co., Ltd. Kawagoe Factory (72) Kenichiro Kawasaki 4,2610 Hanazono, Tokorozawa City, Saitama Pioneer Stocks Company Tokorozawa Factory (56) References JP-A-63-231757 (JP, A) JP-A-64-48256 (JP, A) Actually developed Shou 60-102747 (JP, U)

Claims (9)

[Claims] 1. A tape speed control means for detecting and controlling the running direction and speed of a tape, a clock reproducing means for reproducing a clock from a reproduced digital signal, and a frequency voltage for generating a voltage according to the frequency of the reproduced clock. A recording / reproducing apparatus having a converting means and applying an output voltage of the frequency-voltage converting means to a rotary head driving motor so as to control the relative speed of the rotary head and the tape to be a constant value. Recording signal detecting means for determining the presence or absence of a signal, rotational speed detecting means for detecting the rotational speed of the rotary head driving motor, and the rotational speed detecting means when the recording signal detecting means determines that there is no recording signal. The rotation speed of the rotary head driving motor indicated by the output signal of the tape speed detected by the tape speed control means Based on the signal indicating the direction, the recording and reproducing apparatus characterized by comprising a rotation control means for controlling so that the value higher than a certain value of the relative velocity. 2. The recording / reproducing apparatus according to claim 1, wherein the rotation control means immediately performs the rotation when the recording signal detecting means determines that there is no recording signal at the start of tape running. A recording / reproducing apparatus, wherein the number of revolutions of a head driving motor is controlled to be higher than a final target value of relative speed. 3. The recording / reproducing apparatus according to claim 1, wherein the rotation control means always determines the rotation speed of the rotary head when the recording signal detection means determines that there is no recording signal.
A recording / reproducing apparatus characterized in that control is performed such that the relative speed is higher than a constant value by a threshold value. 4. The recording / reproducing apparatus according to claim 1, wherein the rotation control means drives the rotary head after a lapse of a predetermined time after the recording signal detection means determines that there is no recording signal. A recording / reproducing apparatus, wherein the number of rotations of a motor is controlled to be higher than a final target value of relative speed. 5. The recording / reproducing apparatus according to claim 1, wherein the rotation control means, when the tape running speed reaches a final target value when there is no recording signal after starting the tape running, A recording / reproducing apparatus, wherein the number of rotations of a rotary head driving motor is controlled to be higher than a final target value of relative speed. 6. The recording / reproducing apparatus according to claim 1, wherein the recording signal detecting means determines that there is a recording signal when the number of envelopes of the reproduced signal is equal to or more than a threshold value. Recording and reproducing device. 7. The recording / reproducing apparatus according to claim 1, wherein the recording signal detecting means determines that there is a recording signal when the time width of the envelope of the reproduced signal is equal to or more than a threshold value. Recording and reproducing device. 8. The recording / reproducing apparatus according to claim 1, wherein the recording signal detection means determines that there is a recording signal when the number of envelopes whose time width is equal to or greater than a threshold value is equal to or greater than the threshold value. A recording / reproducing apparatus characterized by: 9. The recording / reproducing apparatus according to claim 1, wherein the recording signal detecting means inputs a signal obtained by envelope-detecting a reproduced signal, and compares the envelope-detected signal with a reference voltage. And a binarizing comparator, and a discriminating unit for discriminating the presence / absence of a recording signal from the binarized signal.