JP3155647B2 - Magnetic reproducing apparatus and magnetic recording / reproducing apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic reproducing apparatus and a magnetic recording / reproducing apparatus of a helical scan type such as a VTR (video tape recorder) and a digital audio signal recording / reproducing apparatus. TECHNICAL FIELD The present invention relates to a control technique for a rotary head drum motor capable of controlling a rotary phase of a rotary head without providing a means for detecting a specific rotary phase.

[0002]

2. Description of the Related Art Conventionally, in a VTR or the like, the following method has been used to detect an absolute rotation phase of a rotary head drum.

[0003] For example, "Introduction to Home VTR" by Corona Company
(Pp. 141-144), a DPG (Drum Phase G) attached to a specific portion of a rotary head drum is used.
The absolute rotational phase was detected by detecting a change in the magnetic field caused by a magnet with a DPG coil fixed outside the drum.

In the apparatus described in Japanese Patent Application Laid-Open No. 4-307452, a plurality of special synchronization signals are recorded in advance on a track on the tape, and the head detects the synchronization signal during reproduction, whereby the tape is read. The rotational phase of the head with respect to was detected.

[0005]

An apparatus using the above-described method of detecting an absolute rotational phase by using a DPG requires hardware such as a DPG magnet, a DPG coil, a DPG signal amplification and waveform shaping circuit, thereby reducing costs and reducing the system. No particular consideration was given to miniaturization.

In an apparatus using the above-described method of recording a plurality of special synchronization signals on a track on a tape in advance, a tape which has been recorded by a conventional various recording / reproducing method which does not record the special synchronization signal is used. No particular consideration has been given to the method of detecting the phase of the rotary head during reproduction or recording (no particular consideration has been given to compatibility with various conventional recording / reproducing methods).

Accordingly, a technical problem to be solved by the present invention is to solve the above-mentioned problems of the prior art, and an object of the present invention is to maintain compatibility with various conventional recording / reproducing methods. Another object of the present invention is to provide a magnetic reproducing apparatus and a magnetic recording / reproducing apparatus which can control a rotational phase of a rotary head in a configuration in which hardware for detecting an absolute rotational phase by a DPG is removed.

[0008]

Means for achieving the above object are as follows. First, when reproducing a recorded tape, a vertical synchronizing signal (hereinafter referred to as a V.sync signal) of a recorded video signal is used to specify a track on the tape in many of various recording / reproducing methods currently used. Position is recorded at the V. position.
The rotation phase of the rotary head drum is controlled using the sync signal, thereby eliminating the need for the DPG.

That is, the motor control means (hereinafter referred to as a drum control system) for the rotary head drum controls the rotary head to an appropriate speed and phase, and the motor control means for tape running (hereinafter referred to as a capstan control system). In the following, the tape running is controlled to an appropriate speed and phase. Here, the speed control means of the rotary head drum uses a frequency generation means proportional to the rotation frequency, generates a speed error signal for keeping the period of the generated signal constant, and performs speed control.
The phase control means of the rotary head may divide a signal to be synchronized (for example, a color subcarrier) to a frequency equal to the signal generated by the frequency generation means or at least to a frequency higher than the rotation frequency of the rotary head. A signal is generated, and a phase error signal for synchronizing the signal with a signal generated by the frequency generating means with an appropriate phase difference is generated to perform phase control. When the rotary head is rotating in synchronization with the reference phase signal, each cycle of the signal generated by the frequency generating means is appropriately numbered by one rotation of the rotary head or a plurality of rotation cycles. A switching signal for a plurality of rotating heads used at an appropriate timing is generated from a specific phase of a cycle of an appropriate number in the numbering. By the head switching signal, the V.V. sy
If the nc signal can be detected, the V.nc signal is detected. The above numbering is properly initialized based on the sync signal. V. If the sync signal cannot be detected, the number used as the reference for generating the head switching signal is sequentially shifted and the V.sync signal is sequentially shifted. Detect sync signal. Here, even if the reference number is shifted over one rotation of the rotary head, the V.V. If the sync signal cannot be detected, the V.V. sync
Signal can be detected. V. After detecting the sync signal, initialization of numbering is performed in the same manner as described above. From the above,
The rotation phase of the rotary head when the rotary head scans a specific position on the tape can be defined by the cycle of the signal generated by the frequency generation means, and a head switching signal having an appropriate phase can be generated.

When recording is performed on a recorded tape, immediately after the start of the rotary head and prior to the start of recording, the above V.V. Cause detection of sync signal. After the rotation phase of the rotary head with respect to the tape is determined, the recording operation is permitted.

When recording is to be performed on a non-recording tape, after the rotation head is started, first, the above-described V.V. Cause detection of sync signal. Here, even if the reference number of the head switching signal is sequentially shifted by one rotation after the phase inversion of the rotating head, the V.V. If the sync signal cannot be detected, it can be determined that the tape is a non-recording tape. After discrimination of a non-recording tape, tape running is stopped and recording is performed with only one head (recording is performed only during a period when a specific head is selected, instead of fixing a head switching signal). Then, the phase locked state of the rotating head is not changed, and the phases of the reproducing head and the head switching signal are all reproduced under the same conditions as in the recording. Then, the reproduced RF signal is appropriately detected, and if there is any loss, the generation reference number of the head switching signal is shifted and recording is performed again. Then, reproduction is performed again and the lack of the RF signal is inspected. This operation is repeated, and when the reproduced RF signal is no longer lost, normal recording can be performed with the head switching signal generated based on the numbering thereafter. As described above, even if there is no information previously recorded on the tape, the rotation phase of the rotary head with respect to the tape can be defined by the generation signal of the frequency generation means, and a head switching signal having an appropriate phase can be generated.

[0012]

[Function] The recorded tape is reproduced and reproduced. The means for detecting the rotation phase of the rotary head from the sync signal changes only the phase of the head switching signal without changing the rotation phase lock state of the drum. Therefore, if a track having the same azimuth angle is scanned, V.D. Sync signal can be detected. If the azimuth angles do not match, the V.V. Sync signal can be detected. Then, the playback V. The phase at the time when the sync signal is detected is almost the phase at which the head scans a specific position on the tape (the position where the V.sync signal is recorded). Therefore, the reproduction V. Based on the sync signal, the numbering of each cycle of the signal generated by the frequency generating means is performed anew, and thereafter, if the numbering is repeated periodically, the timing at which each head contacts the tape is determined by the number. Can be specified.

V. The numbering of each cycle of the generated signal of the frequency generating means initialized after the detection of the sync signal is as follows:
Stored until the rotating head drum stops. Therefore,
When recording is performed on a recorded tape, the above operation is performed when the rotary head is activated. Therefore, the phase of the rotary head with respect to the tape is correctly recognized, and a correct recording operation is performed.

On the other hand, when recording is performed on a non-recording tape, the V.V. The sync signal is recorded at a position irrelevant to the position in the tape format standard, and is not useful. However, V. The fact that the sync signal is not recorded at the correct position means that the recording position is shifted with respect to the tape, and if the reproduction is performed under the same conditions, there is a tape non-contact period of the head. Therefore, if the loss of the reproduced RF signal is monitored, it is possible to determine whether the head switching phase is correct or incorrect, and it is possible to determine that the state where the RF signal is not lost is the correct phase.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments shown in FIGS. First, FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIGS. This embodiment is an example of application to a reproduction VTR. First, the principle operation of the present embodiment will be described with reference to FIG. Here, FIG. 2A is a schematic diagram showing the relationship between the tape and the head and a specific configuration example of the frequency generating means. FIG. 2 (b) shows the operation and V.V. FIG. 9 is a waveform diagram for explaining the numbering of the generation signal of the frequency generation means based on the detection of the sync signal and the generation process of the head switching signal based on the numbering.

In FIG. 2A, reference numeral 2 denotes a tape (magnetic tape) which is strongly wound 180 ° around a drum on which a rotary head is mounted, and 25 denotes a DFG which rotates together with the rotary head.
(DrumFrequency Generator) magnet, 26 is a patterning coil (DFG coil) for detecting a magnetic field change by the rotating DFG magnet 25, 27 is a channel 1 head (hereinafter referred to as CH1 head or simply CH1), 28 is a channel 2 head (hereinafter CH2). Head or simply CH2).

Next, according to FIGS. 2A and 2B, the DFG
The generation process of will be described. When the DFG magnet 25 rotates, a current is generated in the radial direction of the DFG coil 26. When the radial pattern comes to the center of each magnetic pole, the current value becomes maximum. In FIG. 2A, when the radial pattern of the DFG coil 26 is at the center of the magnetic pole, this state corresponds to the peak of the sine wave in FIG. 2B. Now DF
When the DFG magnet 25 rotates by an angle (15 °) shown in FIG. 2A from a state where the pattern in the radial direction of the G coil 26 is at the center of the magnetic pole, the pattern of the adjacent DFG coil 26 becomes Come to the center. At this time, the current has the maximum value, but the direction is opposite to the above. Therefore,
This corresponds to the valley bottom of the sine wave in FIG. Therefore, in the present DFG, a one-cycle sine wave is generated by the rotation of the DFG magnet 25 by 30 °. By shaping the sine wave with an appropriate threshold value, a rectangular wave having rising and falling edges at a specific phase of the sine wave is obtained. Thus, the DFG is n times the rotation frequency (n is a natural number determined by the number of magnetic poles and the number of patterns, n in this example)
= 12).

Next, according to FIG. The process of generating the head switching signal from the detection of the sync signal will be described. If the CH1 head 27 rotates and scans a track on the tape 2, the V.V. recorded at a certain time between the rising edge of a certain DFG signal and the rising edge of the next DFG signal. Assume that a sync signal is detected. Here, assuming that the rotating head is rotating at a constant target speed, the CH1 head 27 then moves to V.V. The sync signal is detected between the twelfth rising edge of the DFG signal and the thirteenth rising edge of the DFG signal. Therefore, V. The edge of the DFG signal may be counted after the detection of the sync signal, and the head may be switched at an appropriate timing 29 from the edge of the twelfth DFG signal. Further, when the CH2 head 28 has the V.V. sy
The nc signal is detected between the sixth rising edge of the DFG signal and the seventh rising edge of the DFG signal. Therefore, the heads may be switched at appropriate timing 29 'from the edge of the sixth DFG signal. Here, the timing for switching the head is not necessarily the V. It is not necessary to use the DFG signal immediately before the detection of the sync signal as a reference, and it suffices that the relationship with any one of the DFG signals becomes clear in advance. Also, when the head is on the V.V. After scanning the sync signal, perform appropriate signal processing,
V. It takes some time to detect the presence of the sync signal. However, assuming that the rotating head is rotating at a constant speed, the head actually moves on the track. The phase obtained by scanning the sync signal can be inversely calculated and appropriately reflected on the values of the timings 29 and 29 '. It should be noted that the above V.V. The numbering of the DFG signals based on the sync signal detection may be performed only once when the rotating head drum is started, and thereafter, the numbering may be performed periodically according to the rotation cycle.

The principle operation of the present embodiment has been described above. The overall configuration and the operation of the first embodiment will be sequentially described again, including a specific process until a sync signal is detected. FIG. 1 is a block diagram of a main part of the first embodiment, and its configuration will be described below.

In FIG. 1, reference numeral 1 denotes a rotary head drum on which the two reproducing heads (CH1 head 27 and CH2 head) shown in FIG. 2 are mounted, 2 is the tape described above, 3 is a capstan motor, and 4 is a drum motor. Reference numeral 5 denotes a control signal reproducing head for tracking (hereinafter referred to as CTL signal or simply CTL). Reference numeral 6 denotes a rotary transformer for transferring a reproduction signal from the head to the outside of the rotary drum. Reference numeral 7 denotes a reproduction RF (Radio Frequency) signal. A reproduction RF signal processing circuit for amplifying and switching, 8 is a CFG (Capstan Frequenc) which is proportional to the rotation frequency of the capstan motor 3.
y Generater) signal waveform shaping processing circuit, 9 is a CTL amplifier, 10 is a capstan speed control processing circuit that appropriately generates a CFG generation cycle to generate a speed error signal, and 11 is a phase for performing tracking by the CTL signal. A capstan phase control processing circuit for generating an error signal; 12, a capstan motor driver / amplifier; 13, a reproduction color signal processing circuit for mainly restoring a low-frequency-converted color signal into a carrier color signal; Mainly FM modulation (Fr
A reproduction luminance signal processing circuit 15 for demodulating the luminance signal subjected to the frequency modulation (Equency Modulation). sync signal. sync detection processing circuit, 16 is a capstan control system, 1
7 is a system controller for controlling the processing sequence of the entire system, 18 is a drum control system, 19 is a waveform shaping processing circuit for the DFG signal of the drum motor 4, 20 is a DFG-head relative number for numbering the DFG with reference to the head. A drum speed control processing circuit for appropriately processing a DFG generation cycle to generate a speed error signal;
Reference numeral 22 denotes a drum phase control processing circuit for generating a phase error signal by appropriately processing a phase difference between a DFG and a reference phase signal generated by appropriately dividing the frequency of an original signal to be synchronized (for example, a color subcarrier). And a reference phase generation processing circuit 24 for generating a reference phase signal to be synchronized. Here, the operation of the head and its surroundings is as described with reference to FIG.

Next, a specific configuration from the CH1 head 27 and the CH2 head 28 to the output process of the reproduction RF signal processing circuit 7 will be described with reference to FIG. The reproduced RF signals detected by the CH1 head 27 and the CH2 head 28 are transferred to the outside of the rotary head drum via the rotary transformer 6. After being appropriately amplified in the reproduction RF signal processing circuit 7, only one of the reproduction signals is output according to the head switching signal. Here, when the rotating head drum 1 is activated, the recorded V.V. sy
Since the nc signal has not been detected, there is no choice but to switch the head output signal using a head switching signal generated based on an appropriate DFG. As a result, there is a problem that a head output signal during a period in which the head is not in contact with the tape is selected.

FIG. 4 shows an example of a head switching signal generated based on an appropriate DFG and the output of the CH1 head and the output of the CH2 head at that time. FIG. 4B shows the scanning relationship between the track and the head, and FIG.
This shows a state in which the CH1 head 27 (referred to as + azimuth head) is not in contact with the tape, and the CH2 head 28 (referred to as -azimuth head) is in contact with the tape. In this state, it is assumed that the CH2 head 28 is selected from this moment. Then, the CH2 output becomes as shown in FIG.
Almost half of the head selection period contacts the tape, and-
(Minus) It is in a state where only half of the azimuth track is on-track. The rotating head drum 1 rotates half a turn to
The same result is obtained when one head 27 is selected.

Therefore, the temporary numbering of the DFG is sequentially shifted by the system controller 17. FIG. 5 is a waveform diagram showing this process. Since the rotation phase itself of the rotary head drum 1 has not changed at all, if the reference DFG for generating the head switching signal is sequentially shifted, V.V. Sync signal can be detected.

In the examples shown in FIGS. 4 and 5, the reproduced RF signal is detected from the latter half of the track. However, as shown in FIG. There is a possibility that the reproduced RF signal of the first half of the tape is detected in the latter half of the selection period. In this case, The sync signal can be detected immediately. Immediately after the sync signal is detected, DF
Initialize a counter for G numbering.

When a head switching signal is generated based on an appropriate DFG, it is not known whether the currently selected head is + azimuth or -azimuth. Therefore, as shown in FIG. 6B, there is a possibility that a head and a track having a reverse azimuth are combined even though the head currently in contact with the tape is selected. In such a case, even if the reference DFG for generating the head switching signal is sequentially shifted over one rotation, as shown in FIG. The sync signal cannot be detected. Therefore, even if the reference DFG for generating the head switching signal is shifted by one rotation, the V.V. If the sync signal cannot be detected, the phase lock state of the rotary head drum 1 is changed by an appropriate angle (for example, 180 °), and then the reference DFG of the head switching signal is appropriately determined. Cause detection of sync signal. And V. When the sync signal cannot be detected, the reference DFG is sequentially shifted so that the V.sync signal is always detected. sync signal can be detected. After detecting the sync signal,
Initialize the DFG signal numbering means.

Here, in order to change the phase locked state of the drum by the required angle, a reference phase signal (REF signal) is generated at the same frequency as the DFG signal, as shown in FIG. The phase signals are also numbered. Then, rather than generating a phase error signal that makes the phase difference between each edge of the DFG signal and the reference phase signal constant, a phase error signal for making the number of the DFG signal coincide with the number of the reference phase signal is preferentially generated and output. And control. Then, when the numbers match, a phase error signal for making the phase difference between the edges of the DFG signal and the reference phase signal constant may be generated and controlled.

FIG. 8 shows the V.V. on the recorded tape described above. A specific example of a sequence for appropriately detecting a sync signal and generating a head switching signal having an appropriate phase will be described. Here, the process of temporarily stopping the capstan surrounded by a dotted line is described in V.11. This is a process for reducing the tape that moves during the sync signal detection period or during the phase inversion of the rotary head drum, and may be performed as needed.

As described above, according to the present embodiment, there is an effect that a system which does not require a DPG can be provided while maintaining compatibility with a conventional format.

Next, a second embodiment of the present invention will be described with reference to FIGS. This embodiment is also an example of application to a reproduction VTR as in the first embodiment. However, the first embodiment is an example in which the phase control system of the capstan is performed by the CTL signal, but in the present embodiment, a tape on which four frequency pilot signals are sequentially recorded for each track at the time of recording is used. VT of the type which controls the phase of the tape running by making it coincide with the pilot signal sequentially generated at the time of reproduction.
R. FIG. 9 is a block diagram showing the main part, and its configuration will be described below. However, since most of the configuration is the same as that of FIG. 1, only the configuration of a different part will be described.

In FIG. 9, reference numeral 33 designates an ATF (Au) for generating a tracking error signal in which the amounts of crosstalk pilot signals from the right and left tracks included in the reproduced RF signal should be equal, and performing tracking control of the tape running.
to Track Finding) signal processing circuit.

Next, the operation will be described. The pilot signal is
It must be able to detect even if tracking is not performed correctly. Therefore, the frequency of the pilot signal is generally selected to be a low frequency signal which is less susceptible to azimuth loss. In a portion where the head is not in contact with the tape, there is no crosstalk pilot signal from an adjacent track and no tracking error signal is generated. Thus, if the ATF process is a continuous process, unless the phase relationship between the head scanning and the head switching signal is completely opposite (a head that is not in contact with the tape is always selected).
Tracking is possible even if the phase of the head switching signal is somewhat incorrect. After the capstan phase lock, the V.V. The detection of the sync signal may be performed sequentially. When the head scanning and the scanning of the head switching signal are completely opposite in phase, the discrimination is possible because the pilot signal of the track intended to be scanned cannot be detected. Therefore, in that case, the phase of the head switching signal should be inverted.

FIG. 10 shows a specific example in which the ATF process is a discrete system process. FIG. 10 shows an example in which sampling timing of a head switching signal and an ATF error signal is generated from an appropriate reference DFG. FIG. 10A shows a state in which the CH2 head 28 is in contact with the tape 2 and the CH1 head 27 is out of contact, as in FIG. 4B. Here, temporarily, this state is shown in FIG.
Assuming that the DFG numbering is located at the "0" position,
CH2 at tracking error signal sampling position
Since the head 28 is in contact with the tape 2, sampling is barely possible and tracking is possible. On the other hand, FIG.
If the state (a) is located at the position of the DFG numbering “6” in FIG. 10B, only the state where there is no tracking error is sampled. Therefore,
In this case, the phase of the head switching signal may be inverted based on the presence / absence information of the pilot signal of the track to be scanned from the ATF signal processing circuit 33. However, when the discrimination information of the presence / absence of the pilot signal cannot be obtained, the head switching signal is fixed and the control is performed using only one head information during the period during the capstan phase control as shown in FIG. Let it do. In this way, a correct tracking error signal can be obtained once every two times. Also,
Since the remaining one error signal is zero, there is no adverse effect that would disturb the control direction. After the tracking is completed, the V.V. What is necessary is just to perform a sync signal detection process and determine the phase of the head switching signal. However, when the rotation phase of the drum is reversed, the tracking state changes accordingly. Therefore, the sampling timing of the tracking error signal during or during that time may be generated based on the reference phase signal.

Next, referring to FIG. 11, a description will be given of a specific example in which a rotary head having a different configuration from the rotary head described in the first and second embodiments is used, and an operation in that case. In the rotary head described above, two tracks are used to scan two tracks by one rotation of the drum. In this example, four tracks are scanned by three rotations of the drum using four heads. FIG.
(A) shows the configuration. As shown in the drawing, in the present example, unlike the configuration of FIG. 2A, the winding angle of the tape 2 is slightly more than 270 °. The arrangement of the CH1 head 27 and the CH2 head 28 having different azimuth angles is 90 °, and the CH3 head 34 having the same azimuth angle as the CH1 head 27 and the CH4 head 35 having the same azimuth angle as the CH2 head 28 are CH1 and CH2, respectively. CH2
It is added at a position of 180 ° with respect to the heads 27 and 28. Although there is no essential difference regarding the head configuration, the DFG is changed to one that is generated six times in one rotation of the drum for convenience of explanation.

Next, the operation of the rotary head drum will be described. Now, assuming that the CH1 head 27 starts to contact the tape 2, one track is scanned by a rotation of 270 ° therefrom. And the CH1 head 27
When the head is separated from the tape 2, the CH2 head 28 starts to come into contact with the tape 2, and track scanning by the CH2 head 28 is started. Hereinafter, the CH3 head 34, the CH4 head 35, the CH1 head 27,... Sequentially scan the tracks. Therefore, the head switching signal has four phases as shown in FIG. Here, in the case of the first embodiment, the tracking control is still performed by the CTL signal. By detecting the sync signal, the DFG can be appropriately numbered.
On the other hand, in the case of the second embodiment, if the tracking error signal can be sampled twice or more in one scanning period,
By properly selecting the sampling interval, sampling can be always performed during the period in which the tape is in contact with the tape.
Therefore, tracking can be performed more easily than in the case of the first embodiment. After tracking is completed, the same V.V. sy
It is sufficient to detect the nc signal and appropriately number the DFG.

Next, the relationship between the generation phase of the DFG signal and the mounting position of the head in the first and second embodiments will be described. The video signal recorded on the track actually has a variation in the recording position. Therefore, V.V. provides a source for numbering DFG signals. The position of the sync signal also varies. This situation is schematically shown in FIG.
(A) of FIG. Therefore, even if the same device reproduces a different tape, the V.F.
A sync signal is detected. For this reason, the V.V.
When a tape on which a sync signal is recorded is reproduced,
If the edge of the sync signal is too close to the edge of the DFG signal, sync
When the signal varies, it becomes impossible to identify each head and the edge of the DFG signal. This state is shown in FIG. The phase relationship between the head and the DFG signal is shown in FIG.
As shown in FIG. What is necessary is just to arrange in the positional relationship in consideration of the variation of the sync signal position.

Next, a specific example of the means for detecting the discrete relative rotational phase of the rotary head other than the DFG will be described with reference to FIG. FIG. 13A schematically shows the relationship between a coil and a magnet of a brushless motor of a three-phase coil 8-pole magnet. Here, 36 is a rotor magnet for driving a motor, 37 is a U-phase coil, 38 is V
A phase coil 39 is a W-phase coil. FIG. 13B is a diagram showing the waveform of the induced voltage of the coil of each phase.
In a three-phase motor, generally, current is applied to only two coils at the same time. That is, phase switching is performed several times during one rotation. Here, considering the U-phase as a reference, the stage in which the induced voltage of the U-phase tries to shift from the lower side to the higher side with respect to the midpoint of the sine wave voltage (that is, the magnetic field around the coil is changing) Switch to drive to the U-V phase,
At the stage where the induced voltage of the W phase changes from a high side to a low side with respect to the middle point, the drive is switched to the U-W phase drive, and
At the stage where the induced voltage of the phase changes from the lower side to the higher side with respect to the midpoint, the driving is switched to the VW phase. in this way,
In a three-phase brushless motor, the midpoint of the induced voltage of each phase is detected. In this example, since the midpoint detection is performed six times for a rotation angle of 90 °, it can be said that the information is discrete relative rotation phase information in units of 15 °. Therefore, it is also possible to detect the position of the head using the phase switching signal of the motor instead of using the DFG signal.

As described above, the V.V. sync
The numbering of the DFG signals by the signals and the generation of the head switching signal based on the signals have been described. Next, the generation of the head switching signal during recording will be described with reference to FIGS. FIG. 14 shows the CTL shown in FIG.
This is a system in which a signal processing system and a control system for recording are added to a reproduction system having a tape running control system based on signals. FIG. 15 shows a system in which a signal processing system and a control system for recording are added to the reproducing system having the tape running control system based on the ATF processing shown in FIG.
Hereinafter, the configuration will be described. However, since there are many portions that overlap with FIGS. 1 and 9, only different portions will be described.

First, in FIG. 14, reference numeral 40 denotes a recording rotary transformer; 41, a recording RF signal processing circuit for appropriately amplifying a recording RF signal generated by appropriately frequency-multiplexing a recording color signal and a luminance signal; The recording color signal processing circuit 43, which mainly converts the carrier color signal into a low frequency and generates a part of the recording RF signal, 43 mainly converts the luminance signal into an F signal.
A recording luminance signal processing circuit 44, which generates a part of the recording RF signal by performing M-modulation, generates a V.V. of the recording luminance signal from a signal before or during the luminance signal processing. Sync signal is detected. A sync signal detection processing circuit, 45 is a recording / reproduction switch, and 5 is a CTL signal head for both recording and reproduction. The configuration in FIG. 15 almost overlaps with the components in FIGS. 9 and 14, and the different component in FIG. 15 is a recording pilot signal generation processing circuit for ATF signal processing of 49.

Next, the operation at the time of recording using FIGS. 14 and 15 will be described. The processing at the time of recording will be roughly described. The processing differs depending on whether a tape to be recorded is a recorded tape or a non-recorded tape.

First, assuming that the tape is a recorded tape, before starting the recording operation when the rotating head drum is activated, the V.V. Cause detection of sync signal. Also, the phase of the DFG signal is clarified by the numbering of the DFG signal. At the time of reproduction, the reference recording phase signal generated at an appropriate phase is replaced with the V.V. of the recording luminance signal. The DFG signal is generated in synchronization with the sync signal, and the properly numbered DFG signal is synchronized with the reference phase signal. In this way, when the head comes to an appropriate position on the tape, the V.V. The sync signal will be recorded. FIG. 16 shows a sequence of the above processing. Here, V.F. In the process of detecting the sync signal, after appropriately changing the phase locked state of the drum, even if the temporary numbering of the DFG signal is completed, the V.V. If no sync signal is detected, it can be determined that the tape is a non-recording tape. Therefore, in that case, another process is performed.

Prior to the description of the processing, first, FIG.
From the recording RF signal processing circuit 41 to the recording head (CH
The process of processing up to one head, CH2 head) will be described in more detail. As shown in FIG. 17, the recording RF signal is appropriately switched between two paths by a head switching signal, and then amplified and supplied to each head via the rotary transformer 40.

Here, when it is determined that the tape is a non-recording tape as described above, the tape running is first stopped. Then, the recording heads are fixed to one (instead of fixing the head switching signal, only one of the recording heads is enabled while the head switching signal is enabled. That is, only the signal of one path is used. Mask), and perform temporary recording. Then, since recording is performed based on an appropriate DFG signal, a recording track is generated at an appropriate phase as shown in the upper part of FIG. Subsequently, this track is reproduced under the same conditions as in the previous temporary recording. Then, the part where the head does not touch the tape is always reproduced. Here, since it is known that this tape is non-recording, the detecting means (the envelope detecting circuit 46 and the binarized waveform shaping circuit 4) of the reproduced RF signal as shown in FIG.
7, or by using the envelope detection circuit 46 and the A / D converter 48), the system controller 17 can determine which period the tape has not been in contact with. Based on this information, the reference of the DFG signal is appropriately changed, the phase of the head switching signal is re-created, and the temporary recording and reproduction are repeated. As a result, if the record missing portion disappears, the V.V. By detecting the sync signal to clarify the rotation phase of the DFG signal, recording becomes possible. FIG. 19 shows the sequence of this process. In addition, if the portion where the temporary recording is performed is erased by using a rotary erase head, unnecessary information due to the temporary recording operation is not left.

With the above arrangement, provisional recording can be performed without invalidating the recording information previously recorded by the user, and the phase of the rotary head drum can be correctly detected without any pre-recorded information. You can do it.

Further, all of the above embodiments are performed by detecting a synchronizing signal of an analog video signal. However, for example, when recording a digital audio signal or a digital video signal, the same processing can be performed by using an address signal or the like recorded at a specific position on a track as a reference for numbering the DFG signal.

[0045]

As described above, according to the present invention, the DPG generating mechanism can be eliminated while maintaining compatibility with a conventional magnetic recording / reproducing apparatus for video signals. Therefore, this
This has the effect of reducing the cost and size of the system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of a reproduction VTR according to a first embodiment of the present invention.

FIG. 2A is an explanatory diagram showing a specific example of a DFG signal generating unit according to the first embodiment of the present invention, and FIG. 2B is a waveform diagram for explaining its operation.

FIG. 3 is a block diagram illustrating switching of an RF signal reproduced from a reproducing head according to a first embodiment of the present invention;

FIG. 4A is a waveform diagram showing an example of a reproduced RF signal when the phase of the rotary head selection signal and the phase of the rotary head are not in a correct relationship according to the first embodiment of the present invention, and FIG. FIG. 4 is a schematic diagram showing a relationship between a track and head scanning in that case.

FIG. 5 is a waveform diagram showing a process in which the phase of the selection signal of the rotary head and the phase of the rotary head shift from an incorrect state to a correct state in the processing according to the first embodiment of the present invention.

FIG. 6 is a waveform diagram showing another example of the reproduced RF signal in a state where the phase of the selection signal of the rotary head and the phase of the rotary head are incorrect according to the first embodiment of the present invention.

FIG. 7 is a waveform diagram for explaining a specific example in the case where the rotation phase itself of the rotary head is changed in the processing according to the first embodiment of the present invention.

FIG. 8 is a flowchart showing a specific example of a processing sequence from the detection of a vertical synchronization signal recorded on a track to the detection of an absolute rotation phase of a rotary head according to the first embodiment of the present invention.

FIG. 9 is a block diagram showing a main configuration of a reproducing VTR according to a second embodiment of the present invention.

FIG. 10A is a schematic diagram showing the relationship between a track and head scanning when the phase of the rotary head selection signal and the phase of the rotary head are not in a correct relationship according to the second embodiment of the present invention; () Is a waveform diagram showing an example of a reproduced pilot signal in that case.

FIG. 11A is an explanatory diagram showing another specific example of a DFG signal generating unit according to the present invention, and FIG. 11B is a waveform diagram for explaining its operation.

FIG. 12A is a schematic diagram of a track showing a variation in the position of a vertical synchronization signal recorded on the track,
(B) shows the position of the vertical synchronization signal and the DF that differ for each tape.
FIG. 3C is an explanatory diagram showing a relationship with a G signal, and FIG.
FIG. 4 is an explanatory diagram showing a positional relationship between an FG signal, a vertical synchronization signal, and a head.

13A is a schematic diagram showing a configuration of a three-phase motor for driving a rotary head as another example of a means for detecting a discrete relative rotation phase of a rotary head according to the present invention, and FIG. FIG. 4 is a waveform diagram showing a phase switching point.

FIG. 14 shows a VT for recording / reproduction according to a third embodiment of the present invention.
FIG. 3 is a block diagram illustrating a configuration of a main part of R.

FIG. 15 is a VT for recording / reproduction according to a fourth embodiment of the present invention.
FIG. 3 is a block diagram illustrating a configuration of a main part of R.

FIG. 16 is a flowchart showing a processing sequence for detecting an absolute rotation phase of a rotary head from a vertical synchronizing signal recorded on a track, and performing a non-recording determination according to a third and a fourth embodiment of the present invention. It is a flowchart figure which shows the specific example of a process order.

FIG. 17 is a block diagram showing a processing system until a recording RF signal reaches a recording head according to the third and fourth embodiments of the present invention.

FIG. 18 is a schematic diagram of a track showing a process in which the rotation phase of the rotary head is sequentially corrected to a correct position when using a non-recording tape according to the third and fourth embodiments of the present invention.

FIG. 19 is a flowchart showing a specific example of a processing order until an absolute rotation phase of a rotary head is detected when a non-recording tape is used, according to the third and fourth embodiments of the present invention.

FIG. 20 is a reproduction RF according to the third and fourth embodiments of the present invention.
FIG. 4 is a block diagram showing two specific examples of a means for determining a missing signal.

[Explanation of symbols]

 Reference Signs List 1 rotating head drum 2 magnetic tape (tape) 3 capstan motor 4 drum motor 5 CTL head 7 reproduction RF signal processing circuit 10 capstan speed control processing circuit 11 capstan phase control processing circuit 14 reproduction luminance signal processing circuit 15 reproduction V. sync signal detection processing circuit 16 capstan control system 17 system controller 18 drum control system 20 DFG-head relative numbering processing circuit 21 drum speed control processing circuit 22 drum phase control processing circuit 23 reference phase generation processing circuit 25 DFG magnet 26 DFG coil 27 CH1 head 28 CH2 head 33 ATF signal processing circuit 34 CH3 head 35 CH4 head 36 Rotor magnet 37 Stator coil U phase 38 Stator coil V phase 39 Stator coil W phase 41 Recording RF signal processing circuit 43 Recording luminance signal processing circuit 44 Recording V . sync signal detection circuit 46 envelope detection circuit

──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Kaniwa, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Visual Media Research Laboratory, Hitachi, Ltd. (72) Hiroya Abe 292, Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa, Japan (72) Inventor Yoshio Narita 1410 Inada, Katsuta, Ibaraki Pref. AV Equipment Division, Hitachi, Ltd. (56) References JP-A-63-257488 (JP, A) JP-A-4 -307452 (JP, A) JP-A-6-217580 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 15/467 G11B 15/473 H04N 5/93

Claims (10)

(57) [Claims] 1. A magnetic reproducing apparatus for reproducing a signal by sequentially scanning a signal recorded on a track formed obliquely on a tape with a rotary head, wherein a specific signal is recorded at a specific position on the track. Used tape is used for reproduction, a frequency generation means for generating a signal having a frequency proportional to the rotation frequency of the rotary head, a detection means for detecting the specific signal from the reproduction signal, and a signal generated by the frequency generation means Numbering means for periodically numbering the rotation head by one rotation or a plurality of rotations with respect to the detection time point of the specific signal for each cycle; and generating signals of the frequency generation means ordered by the numbering means. Means for generating a signal during the scanning period of the rotary head based on a specific phase of a cycle of an appropriate number as a reference. Raw devices. 2. The method according to claim 1, wherein the position of the specific signal recorded on the track on the tape is allowed to have an appropriate variation, and the cycle of the signal generated by the frequency generating means is equal to the specific signal. The specific phase of the cycle of the generated signal of the frequency generating means which is first detected after the detection of the specific signal is a cycle larger than the width of the variation and the variation of the specific signal, A magnetic reproducing apparatus characterized in that a positional relationship between the rotating head and the frequency generating means is set so that the phase is unique during one rotation. 3. The signal according to claim 1, wherein the signal recorded on the track on the tape is a video signal, and the specific signal is a vertical synchronizing signal of the video signal. A magnetic reproducing apparatus, wherein the numbering of each cycle of the signal to be performed is performed by the vertical synchronization signal. 4. The vertical synchronizing signal recorded in a track on the tape according to claim 3, wherein the position of the vertical synchronizing signal is allowed to have an appropriate variation, and the period of the signal generated by the frequency generating means is equal to the vertical synchronizing signal. The specific phase of the cycle of the generated signal of the frequency generation means which is first detected after the detection of the vertical synchronization signal, even if there is a variation in the vertical synchronization signal, is a cycle larger than the width of the signal variation, A magnetic reproducing apparatus characterized in that a positional relationship between the rotating head and the frequency generating means is set so as to be a unique phase during one rotation of the rotating head. 5. A magnetic recording / reproducing apparatus for reproducing a signal by sequentially scanning a signal recorded on a track formed obliquely on a tape with a rotary head, or re-recording a signal on the track by the rotary head. A recorded tape on which a specific signal is recorded at a specific position on the track is used for reproduction or re-recording; frequency generating means for generating a signal having a frequency proportional to the rotation frequency of the rotary head; Detecting means for detecting a specific signal; and numbering means for periodically numbering each cycle of the signal generated by the frequency generating means by one or more rotations of the rotary head with reference to the time of detection of the specific signal. With reference to the specific phase of the cycle of the appropriate number of the generated signal of the frequency generating means ordered by the numbering means. Means for generating a signal during a scanning period of the rotary head, wherein when the rotary head is started, each cycle of a signal generated by the frequency generating means is numbered by the numbering means, and scanning of the rotary head is performed. A magnetic recording / reproducing apparatus for performing a reproducing or recording operation after generating a signal for a period. 6. The method according to claim 5, wherein the position of the specific signal recorded on the track on the tape is allowed to have an appropriate variation, and the period of the signal generated by the frequency generating means is equal to the specific signal. The specific phase of the cycle of the generated signal of the frequency generating means which is first detected after the detection of the specific signal is a cycle larger than the width of the variation and the variation of the specific signal, A magnetic recording / reproducing apparatus characterized in that a positional relationship between the rotary head and the frequency generating means is set so as to be a unique phase during one rotation. 7. The signal according to claim 5, wherein the signal recorded on the track on the tape is a video signal, and the specific signal is a vertical synchronizing signal of the video signal. A magnetic recording / reproducing apparatus characterized in that the number of each cycle of the signal to be transmitted is numbered by the vertical synchronization signal. 8. The vertical synchronizing signal recorded on a track on the tape according to claim 7, wherein the position of the vertical synchronizing signal is allowed to have an appropriate variation, and the period of the signal generated by the frequency generating means is equal to the vertical synchronizing signal. The specific phase of the cycle of the generated signal of the frequency generation means which is first detected after the detection of the vertical synchronization signal, even if there is a variation in the vertical synchronization signal, is a cycle larger than the width of the signal variation, A magnetic recording / reproducing apparatus characterized in that a positional relationship between the rotating head and the frequency generating means is set so that the rotating head has only one phase during one rotation of the rotating head. 9. A tape is formed by obliquely contacting a rotary head with a tape to form an oblique track on the tape and sequentially record signals, or a signal of the track already diagonally formed on the tape is read by the rotary head. In the magnetic recording / reproducing apparatus for sequentially reproducing, a frequency generating means for generating a signal having a frequency proportional to the rotation frequency of the rotary head, a missing determining means for determining missing of the reproduced signal, and a signal generated by the frequency generating means. Numbering means for periodically numbering the cycle with one or more rotations of the rotary head based on an appropriate reference;
Means for generating a signal during a scanning period of the rotary head based on a specific phase of a cycle of an appropriate number of the generated signal of the frequency generating means ordered by the numbering means. Provisional recording and reproduction are performed, the presence or absence of a reproduction signal loss is determined by the loss determination means, and the reference cycle number for generating the signal of the head scanning period is appropriately changed according to the determination information. A magnetic recording / reproducing apparatus characterized in that the recording operation is performed in a state where the generation of the signal during the head scanning period is held based on the changed numbering. 10. A rotating head is made to contact the tape obliquely to form an oblique track on the tape and record signals sequentially.
Alternatively, in a magnetic recording / reproducing apparatus for sequentially reproducing the signals of the tracks already formed obliquely on the tape by the rotary head, a recording / non-recording determination for determining whether or not a signal is recorded on the tape. Means, frequency generating means for generating a signal having a frequency proportional to the rotation frequency of the rotary head, missing discrimination means for discriminating a lack of a reproduction signal, and appropriate period for each cycle of a signal generated by the frequency generating means. A numbering means for performing periodic numbering by one or more rotations of the rotary head based on a reference; and a specific phase of a cycle of an appropriate number of generation signals of the frequency generating means ordered by the numbering means. Means for generating a signal during the scanning period of the rotary head as a reference. Reproduction is performed, and the presence or absence of a reproduced signal loss is determined by the loss determining means. According to the determination information, the number of the reference cycle for generating the signal of the head scanning period is appropriately changed, and the changed is performed. A magnetic recording / reproducing apparatus wherein a recording operation is performed in a state where generation of a signal during the head scanning period is held based on numbering in the state.