JPH0743884B2 - Information signal recording / reproducing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical scan type magnetic recording / reproducing apparatus, and in particular, a recording track on a magnetic tape is divided into a plurality of sections.
The present invention relates to an information signal recording / reproducing apparatus suitable for recording a plurality of PCM signals on each of the divided tracks.

[Background of the Invention]

Recent helical scan VTRs (video tape recorders) tend to improve the quality of reproduced audio. As a concrete means, a voice signal is converted into a PCM signal, and 1
A method of performing time-axis compression for each field period and recording on a track section formed during extension of the video signal recording track and during a period (overlap period) in which a plurality of magnetic heads simultaneously scans the tape is performed. Are known.

In a VTR compatible with time-axis compression PCM recording of such an audio signal, a time-axis compression PCM audio signal is originally recorded on a track on which a video signal is originally recorded, as described in JP-A-58-222402. Something to record is proposed. This is for dividing a video signal recording track into, for example, 5 and recording time-axis compressed PCM audio signals, respectively, so that a total of 6 channels of stereo audio including an overlap period can be recorded. Therefore, when this VTR is used exclusively for audio, a recording time that is six times as long as when it is used for normal video is possible.

In order to record and reproduce multiple channels of time-axis compressed PCM audio signals, a new playback signal extraction method, tracking control method, time-axis compressed PCM audio signal generation timing control etc. is necessary.

[Object of the Invention]

It is an object of the present invention to provide an information signal recording / reproducing apparatus capable of recording / reproducing a video signal and a 1-channel PCM audio signal and recording / reproducing a plurality of PMC audio signals.

[Outline of Invention]

In order to achieve the above object, the present invention, in the case of recording / reproducing PCM audio signals of a plurality of channels, by shifting the phase of the rotary head phase detection signal according to the recording / reproducing channel, the video signal at the time of recording. Enables recording of time-axis compressed PCM audio signals on multiple recording tracks,
During playback, the time-axis compressed PCM audio signal recorded on the video signal recording track should always be output from the PCM signal output terminal of the playback lamp. In addition, as a tracking control method during playback, ATF (Automatic Track Finding)
When a video signal is played back, a pilot signal frequency-multiplexed with the video signal is used. On the other hand, when playing back a time-axis compressed PCM audio signal recorded over multiple channels, it is recorded on the channel to be played back. Tracking control is performed using only the pilot signal recorded in the time-axis compressed PCM audio signal by frequency multiplexing.

Example of Invention

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

FIG. 1 is a time axis compression of 6 channels to which the present invention is applied.
A VTR that records and reproduces PCM audio signals (this mode is called multi-PCM mode) and records and reproduces video signals and 1-channel time-axis compressed PCM audio signals (this mode is called video recording / reproducing mode). FIG. 2 is a system block diagram, and FIGS. 2 and 3 are diagrams showing the positional relationship between the track pattern and the tape and cylinder in the video recording / reproducing mode and the multi-PCM mode, respectively. In FIG. 1, 1
Is an input terminal of the channel selection signal in the multi-PCM mode, 2 is an input terminal of the switching signal Multi H between the multi-PCM mode and the video recording / reproducing mode, 3 and 4 are the input / output terminals of the audio signals respectively, and 5, 6 Are input / output terminals for video signals, respectively. 7 is a multi-channel PCM controller, which is a PLL (phase locked loop) 8, a channel selector 9,
It is composed of the switch 10. Reference numeral 11 denotes an ID control circuit, which records and reproduces an ID signal having information such as tape count, date, and audio type on a PCM audio signal by time-axis multiplexing. 12 is a PCM signal processing device 13 is a video signal processing device,
14 and 15 are a main servo system and an ATF servo system.

Incidentally, the ATF servo is a pilot signal composed of four kinds of frequencies at the time of recording, for example, f ₁ = 6.5f _H , f ₂ = 7.5f _H , f ₃ = 10.5
f _H , f ₄ = 9.5 f _H (f _H : horizontal sync signal frequency in video signal) is sequentially recorded on the recording track, and at the time of reproduction, the level difference between the pilot signals reproduced from the left and right adjacent tracks is compared, The tape running speed is adjusted so that this level difference is minimized, and the head is controlled so that it can accurately scan a desired track.

Reference numeral 16 is a recording / reproducing amplifier circuit, 17 is a capstan motor, 18 is a capstan, and 19 is a cylinder motor.
20a and 20b are rotary heads, 21 is a drum tack head, 22 is a magnetic tape, 23 is a cylinder, and 100 is a switch.

Now, the operation of the system will be described with reference to the drawings. First, the case of the video recording / playback mode will be described.

In FIG. 1, a video signal input from an input terminal 5 is supplied to a video signal processing device 13, where a luminance signal is frequency-modulated, a chrominance signal is low-frequency converted, and each is frequency-multiplexed and then recorded. It is input to the reproduction amplifier circuit 16. The vertical sync signal SYNC separated from the input video signal is
It is supplied to the main servo system and determines the rotation phase of the cylinder. On the other hand, the audio signal input from the input terminal 3 is
It is supplied to the PCM signal processing device 12, converted into a time-axis compressed PCM audio signal, and sent to the recording / reproducing amplifier circuit 16. the above
The PCM signal processing device 12 has the configuration shown in FIG.

In FIG. 4, the audio signal input from the input terminal 3 is less than half the sampling frequency in the A / D converter (analog / digital converter) 35 in the LPF (low pass wave filter) 30. The dynamic range is limited to 2 by the compression circuit 33 of NR (noise reduction) 32.
After being compressed to one-half, it is input to the A / D converter 35. The A / D converter 35 converts the output signal of the compression circuit 33 into a digital signal and supplies the digital signal to the PCM processor 37. The PCM processor 37 uses the memory 38 to interleave the input digital audio signal and detect an error.
After adding the correction code and the ID signal supplied from the input terminal 28, it is supplied to the recording / reproducing amplifier circuit 16 shown in FIG. 1 together with the timing signal PCM gate as a time-axis compressed PCM audio signal. In this case, the timing of generation of the time-base compressed PCM signal is controlled by the control signal PCM30 supplied from the multi-channel PCM controller 7 shown in FIG. 1 and becomes the timing shown in FIG.

FIG. 5 shows a control signal PC having rotation phase information of the cylinder 23 supplied from the multi-channel PCM controller 7.
The time chart of M30, the generation timing signal PCM gate of the time-axis compressed PCM signal, the input audio signal input at the time of recording, the time-axis compressed PCM signal and the output audio signal output at the time of reproduction are shown. As shown in this figure, the timing of generation of the time-base compressed PCM signal is determined by the phase of the control signal PCM30, that is, the rising and falling edges, and 36 ° period before both edges (36 ° period of the cylinder rotation phase). Is. In the video recording / playback mode, since the switch 10 of the multi-channel controller 7 shown in FIG. 1 is closed to the N side, the control signal PCM30 is equal to the head phase detection signal SW30 produced by the main servo device 14. Has become. The means for generating the head phase detection signal SW30 will be described later, but this signal has shilling rotational phase information, and the head 20a in FIG.
It falls when passing the point, and rises when the head 20b passes the point A. Therefore, time axis compression PC
During the generation period of the M signal (that is, the high level period of the timing signal PCM gate), the heads 20a and 20b operate at T ₁ shown in FIG.
This is the period during which the area of is scanned.

Now, the recording / reproducing amplifier circuit 16 will be described.
The structure of the recording / reproducing amplifier circuit 16 is as shown in FIG. 6, in which 45 surrounded by a broken line is a recording amplifier and 57 is a reproducing amplifier. In the recording amplifier 45, the recording video signal RECV supplied from the video signal processing device 13 shown in FIG. 1 is converted into the pilot signal REC supplied from the ATF servo device by the adding circuit 46.
It is frequency-multiplexed with P, adjusted to a level suitable for recording by the amplifier 48, and then supplied to the L-side input terminals of the switch 50 and the switch 51. Further, the time-axis compression PCM signal RECPCM supplied from the PCM signal processing device 12 is frequency-multiplexed with the pilot signal RECP by the adder circuit 47, and after being brought to a level suitable for recording by the amplifier 49, it is switched by the switches 50 and 51. It is supplied to the H side input terminal. The switches 50 and 51 include a timing signal PCM gate supplied from the PCM signal processing device 12 via the input terminal 25 and a control signal PCM supplied from the multi-channel PCM controller 7 via the input terminal 26.
Switched by 30 logic outputs. As can be seen from the figure, the switch 50 is switched by the control signal SC1 which is the AND output of the PCM gate and PCM30.
When C1 is high, it is closed to the H side terminal, and when C1 is low, it is closed to the L side terminal. Also, switch 51 is a PCM gate and
It is switched by the control signal SC2 which is the AND output of ▼, and is closed to the H side terminal while the control signal SC2 is high and to the L side terminal when the control signal SC2 is low.

Therefore, the timing chart of the recording signal and the control signal described above is shown in FIG. In FIG. 7, 1) and 2) represent periods during which the heads 20a and 20b are scanning the magnetic tape, respectively. 3) is a reference signal REF30 that determines the rotation phase of the cylinder, and 4) is a drum tack pulse TP. 5) is the control signal PCM30 having the above-mentioned cylinder rotation phase information, and 6) is the signal PCM gate indicating the generation timing of the time-base compressed PCM signal. 7), 8) and 9), 10) are recording amplifiers 45, respectively.
The switching control signals SC1 and SC2 and output signals of the switches 50 and 51 in 11) and 11) and 12) are signals actually recorded on the tape by the heads 20a and 20b, respectively. And
13) and 14) are switching control signals SC3 and SC4 of the switches 60 and 61 of the reproduction amplifier 57, and 15) and 16) are reproduction amplifier 57.
Are a time-axis compressed PCM signal PBPCM and a reproduced video signal PBV reproduced by. Therefore, in the video recording / playback mode, the time-axis compressed PCM signal is recorded in the T ₁ period shown in 1) and 2) of FIG. 7, and the video signal is recorded in the period of T ₂ to T ₆ , and its recording pattern. Is as shown in FIG.

Next, the time of reproduction will be described. In FIG. 6, the video signals reproduced by the heads 20a and 20b and the time-axis compression PCM
The signal is the switch 55,56 that is closed to the PB terminal side during playback.
Is input to the amplifiers 58 and 59 via. At this time, head 20a
The signal reproduced from is sufficiently amplified by the amplifier 58,
It is supplied to the L side input terminals of switch 60 and switch 61,
The signal reproduced from the head 20b is sufficiently amplified by the amplifier 59 and supplied to the H side input terminals of the switch 60 and the switch 61. The switching of the switches 60 and 61 is controlled by the logic output of the control signal PCM30 and the mode switching signal Multi H signal supplied from the multi-channel PCM controller 7 shown in FIG. 1 through the input terminal 26 and the input terminal 2. To be done. That is, the switch 61 is a switch switching signal SC4 which is an inverted signal of the control signal PCM30.
This switch switching signal SC4
Is low (therefore, the head 20a is scanning the section of T ₁ shown in FIGS. 2A and 2B) is closed to the L terminal side, and the switch switching signal SC4 is The high period (the period in which the head 20b scans the section T ₁ shown in FIGS. 2A and 2B) is closed to the H terminal side. Therefore, the output signal of the switch 61 outputs the time-axis compressed PCM signal recorded in the period of T ₁ (shown in 15 of FIG. 7). The reproduction PCM signal PBPCM output by the switch 61 is supplied to the PCM signal processing device 12 shown in FIG. 1 via the output terminal 27.

On the other hand, the switch 60 is controlled by the exclusive OR output SC3 of the control signal PCM30 and the mode switching signal Multi H, and is closed to the H side terminal while the switching signal SC3 is high, and is connected to the L terminal side when the switching signal SC3 is low. Closed to. In the video recording / playback mode, since the mode switching signal Multi H is at low level, the switching signal SC3 of the above switch 60
Is a signal similar to the control signal PCM30 (this is an inverted signal of the switching signal SC4 of the switch 61). Therefore,
The switch 60 is switched in the opposite phase to the switch 61,
Period in which the head 20a and 20b is scanning T ₂ through T ₆ section in Figure 2, i.e., outputs a reproduced signal of the section the video signal is recorded continuously. The reproduction video signal PBV which is the output signal of the switch 60 is output to the first terminal through the output terminal 43.
While being supplied to the video signal processing device 13 shown in the figure,
It is sent to a BPF (specific band pass filter) 63. This BPF63
Is the ATF servo four-frequency pilot signal PBP included in the reproduced video signal PBV, and is output as the reproduced pilot signal through the output terminal 44 to the ATF servo device 15 shown in FIG.
Is supplied to.

The video signal PBV reproduced by the reproduction amplifier 57 described above is subjected to signal processing reverse to that at the time of recording by the video signal processing device 13 shown in FIG. That is, the low-frequency converted color signal is returned to the high frequency band, the frequency-modulated luminance signal is frequency-demodulated, and the original signals are respectively added, and then added and output from the video output terminal 6.

On the other hand, the time base compression PCM signal PBPCM output from the switch 61 of the reproduction amplifier 57 is sent to the waveform equalization circuit 40 via the input terminal 27 shown in FIG. This reproduction PCM signal PBPCM is the waveform equalization circuit 40, and the differential characteristics in the tape head system,
After the intersymbol interference due to the band limiting characteristic is canceled, it is supplied to the data strobe circuit 39. Data strobe circuit
The reference numeral 39 identifies the code of the equalized reproduced PCM signal, shapes the waveform, and supplies it to the PCM processor 37. PCM processor
The reproduced PCM signal input to 37 is demodulated, expanded on the time axis, detected / corrected for code errors, and deinterleaved using memory 38 to D / A converter (digital / analog converter) 36. Supplied. At this time, the ID signal added during recording is separated and supplied to the ID control circuit shown in FIG. The reproduced audio signal converted into an analog signal by the D / A converter 36 is sufficiently attenuated by the LPF31 to eliminate unnecessary high frequency components, and then supplied to the dynamic range expansion circuit 34 of the NR32 and expanded to the original dynamic range. , Is output from the output terminal 4 as a reproduced audio signal.

Next, the main servo device in the video recording / playback mode
14 and the ATF servo device 15 will be described. Servo systems are roughly classified into cylinder servo systems and capstan servo systems. Then, speed control and phase control are required for each servo system during recording and reproduction. Of these, the main servo unit 14 is in charge of everything except the phase control of the capstan during playback, and the ATF servo unit 15
Is in charge of phase control of the capstan during playback. The ATF servo device 15 generates a pilot signal RECP of four frequencies which is necessary for reproduction. Hereinafter, a detailed description will be given with reference to FIG.

In FIG. 8, 14 is a main servo device and 15 is an ATF servo device surrounded by a dotted line. The block configurations of these two servo devices are as follows. 65 is a drum tuck pulse TP phase compensation circuit, 66 is a head phase detection signal
SW30 generation circuit, 67 is a 1/2 frequency divider circuit for vertical sync signal SYNC, 6
8 and 71 are switches, 69 is a phase control circuit, 70 is a reference 30 Hz
Signal generation circuits, 72 and 73 are phase comparison circuits, 74 is a frequency divider circuit, 75 and 79 are frequency discriminators, 76 is a switch, 77 and 80 are adders, and 78 and 81 are motor driver amplifiers. Further, 82 is a 4-frequency pilot signal generator, 83 is an amplifier for amplifying the reproduction pilot signal PBP, 84 is a multiplication frequency converter, 85 and 86 are bandpass filters, 87 and 88 are envelope detectors, and 89 is differential. Amplifier,
90 and 95 are switches. 91 is a switch 92, a resistor 94,
A sample and hold circuit composed of a capacitor 93.
In addition, 64 is an input terminal of the vertical synchronizing signal SYNC supplied from the video signal processing device 13 of FIG. 1, 2 is an input terminal of the mode switching signal Multi H, and 25 is a generation timing of the time axis compression PCM signal. Input terminal of the signal PCM gate. 1
7 to 23 are the same as 17 to 23 in FIG.

The outline of the system will be described with reference to the drawing. First, the cylinder servo system will be described. The cylinder servo system controls the heads 20a and 20b to rotate at a constant speed and a constant phase both during recording and during reproduction. The phase control system at the time of recording uses the signal obtained by dividing the vertical synchronizing signal SYNC supplied from the input terminal 64 by 1/2 by the frequency dividing circuit 67, and also the rotation phase of the cylinder 23 (heads 20a, 20b). The tack head 2
Detected by 1 and sent to the head phase detection signal generator 66, and the output head phase detection signal SW30 is used as a comparison signal, and the phase difference between these reference signal and comparison signal is detected by the phase comparator 72 and the phase error is detected. The signal EDI is output to the adder circuit 77.
The switch 68 is a multi-PC on the N side in the video recording / playback mode.
In the M mode, it is closed to the M side, and the switches 71 and 76 are closed to the REC side during recording and to the PB side during reproduction. Cylinder phase control during playback is based on the standard 30Hz signal generation circuit 70
Output signal REF30 is used, and the comparison signal is the same head phase detection signal SW30 as in recording.

In addition, the cylinder speed control system uses the DFG (Dram Frequency Generato) detected by the cylinder motor 19 for both recording and playback.
r) The signal is input to the frequency discriminator 79, speed detection is performed, and the speed error signal EDP is output to the adding circuit 77. The adder circuit 77 adds the phase error signal EDI and the speed error signal EDP, and supplies them to the motor driver amplifier 78. The cylinder motor is the motor driver amplifier 78 above.
It is controlled by the motor control voltage which is the output of the motor and rotates at a constant speed and a constant phase.

Next, the capstan servo system will be described. The capstan servo is for accurately running the tape 22 at a constant speed and a predetermined phase both during recording and during reproduction.

The phase control system during recording compares the 30 Hz signal obtained by dividing the CFG (Capstan Frequency Generator) signal detected from the capstan motor 17 by the frequency dividing circuit 74 with the output signal REF30 of the reference 30 Hz signal generating circuit 70 as the reference signal. The phase difference between the two signals is detected by the phase comparator 73 and output to the adding circuit 80 as the phase error signal ECI.

The phase control during reproduction is performed by the ATF servo device 15, and the phase error signal ATFE is added by the addition circuit 80 via the switch 76.
Is supplied to. The ATF servo device will be described in detail later.

On the other hand, the capstan speed control system, like the cylinder speed control system, inputs the CFG signal to the frequency discriminator 75 during recording and reproduction, performs speed detection, and outputs it to the adding circuit 80 as a speed error signal ECP. To do. Adder circuit 80
Is the phase error signal ECI (when reproducing, the phase error signal ATF
E) and the speed error signal ECP are added and supplied to the motor driver amplifier 81. The capstan motor is controlled by the motor control voltage output from the motor driver amplifier 81.

Now, the operation of the ATF servo device 15 will be described.
In FIG. 8, the reproduction pilot signal PBP supplied from the recording / reproducing amplifier circuit 16 during reproduction is amplified by the amplifier 83 to a predetermined level and then input to the frequency converter 84. The frequency converter 84 detects adjacent crosstalk components before and after the track being reproduced. This is because the pilot signals having frequencies f _{1 to} f ₄ are recorded on the recording tracks in different frequencies in the order of f ₁ , f ₂ , f ₃ , f ₄ , f _1, ... For each track. , For example of the pilot signal
When the head is scanning the track where the frequency of f ₂ is recorded, the pilot signal reproduced from the previous track as adjacent crosstalk is f ₁ , and the pilot signal reproduced from the next track is f ₃ Becomes As described above, the frequency of the pilot signal is, for example, f ₁ = 6.5f
_{H, f 2 = 7.5f H,} f 3 = 10.5f H, f 4 = 9.5f H: are chosen (f _H horizontal synchronizing signal frequency). Here, when the frequency conversion is performed using the output signal f ₂ of the pilot signal generator 82 to obtain the difference frequency component, the pilot signal reproduced from the previous track is reproduced as the f _H component from the next track. The pilot signal is converted to a 3f _H component. The frequency-converted adjacent pilot signals, a band-pass filter 85, 86 is extracted and f _H component and 3f _H components, supplied to respective envelope detector 87 and 88. The two adjacent crosstalk pilot signals whose amplitude levels have been detected by the envelope detectors 87 and 88 are input to the differential amplifier 89 and are used as difference signals. Therefore, when the head is displaced toward the previous track side, the f _H component is less than 3f _H component, and when the head is displaced toward the next track side, the f _H component is greater than 3f _H component. The difference signal of the f _H component and 3f _H component is supplied to the sample and hold circuit 91 which plays an important role in the multi-PCM mode through the switch 90. Since the switch 95 is closed to the N side in the video recording / playback mode, the switch 92 of the sample hold circuit 91 is always
It is in the ON state. The output of the sample and hold circuit 91 is the capstan phase error signal ATFE, which is supplied to the adder circuit 80 via the switch 76. Switch 90
The difference signal f _H −3f _H and the difference signal 3f _H −f _H are switched for each track by the head phase detection signal SW30.For example, the frequency of f ₃ or f ₁ is recorded as the pilot signal. When the head scans the existing track, the pilot signal reproduced from the previous track is contrary to the above.
To 3f _H component is because the pilot signal reproduced from the next track is f _H component.

Next, the multi-PCM mode for recording / reproducing the time-axis compressed PCM audio signal of channel 6 will be described. In the multi-PCM mode, as shown in the tape pattern of FIG. 2 (a), the video signal recording track is divided into, for example, 5 periods from T ₂ period to T ₆ period, and each period is similar to the T ₁ period described above. The time axis compressed PCM signal is recorded. First, the time of recording will be described.

In the multi-PCM mode, it is necessary to control the generation timing of the time-base compressed PCM signal for each channel. The generation timing of the time axis thick gap PCM signal is shown in FIGS. 4 and 5 above.
As described in the figure, it is determined by the control signal PCM30 supplied from the multi-channel PCM controller 7. Therefore, in the multi-PCM mode, six types of control signals with different phases of 36 ° are used for each channel.
PCM30 (hereafter called 6-phase PCM30) is required. This 6 phase
The PCM 30 is generated by the multi-channel PCM controller 7 shown in FIG. The multi-channel PCM controller 7 is a PLL (phase locked loop) 8 that generates 6-phase PCM 30.
And the channel selection signal CHS input from input terminal 1
Channel selector 9 that selects and outputs the control signal PCM30 corresponding to each channel from the above 6-phase PCM30
And the mode switching signal Mult input from the input terminal 2
It is composed of a switch 10 which is switched by i H. An example of a concrete circuit configuration of the multi-channel PCM controller 7 is shown in FIG. 9, and the phase relationship of the 6-phase PCM 30 is shown in FIG. In FIG. 9, 8 surrounded by a dotted line is 6 phase
PCM30 generation circuit, 9 is a channel selector, and 1
0 is a switch. FIG. 10 is a timing chart of the head phase detection signal SW30 supplied from the main servo device 14 and the control signal PCM30 corresponding to each channel.
In Fig. 10, when P1 is the first channel CH-1 and P2 is the second channel CH-2 ... P6 is the sixth channel.
This is the control signal PCM30 when CH-6 is selected. These 6-phase PCM
The time-base compressed PCM signal whose generation timing is controlled by 30 is sent to the recording / reproducing amplifier circuit 16.

Since the video signal is not recorded in the multi-PCM mode, the vertical synchronization signal SYNC of the video signal cannot be obtained during recording. Therefore, in the main servo device 14 shown in FIG. 8, the output signal REF30 of the reference 30 Hz signal generator 70 is used as the reference signal in the speed control of the cylinder servo system, instead of the 1/2 frequency-divided vertical synchronizing signal. . This is the 8th
In the figure, the switch 68 is closed to the M terminal side by the mode switching signal Multi H.

In FIG. 6, the time-axis compression PCM signal RECPCM is added to the recording pilot signal RECP supplied from the ATF servo device by the adding circuit 47 as in the video recording / reproducing mode, and the amplifier is added.
After being amplified to a level suitable for recording at 49, it is supplied to the H side input terminals of the switches 50 and 51. FIG. 11 shows the recording timing of the time compression PCM signal of each channel in the multi PCM mode. In FIG. 11, 17) and 18) represent periods during which the heads 20a and 20b are scanning the magnetic tape, respectively. 19) is control signal PCM30, 20) is time axis compression P
This is a signal PCM gate that represents the timing of CM generation. 2
1) are switching control signals SC1 and SC2 of the switch 50 and the switch 51 in the recording amplifier 45 shown in FIG. (The solid line is SC1 and the dotted line is SC2.) 22) is the head 20a and 20b.
The PCM signals Sa and Sb recorded by the signals 23) and 24) are the PCM signals MSa and MSb from the first channel to the sixth channel recorded by the heads 20a and 20b, respectively.

For example, in the case of recording on the third channel CH-3, from the multi-channel PCM controller 7 shown in FIG. 1, the CH-3 PCM30 shown in FIG. 11 (19) (this is the head position detection signal SW30). Is delayed by 36 ° × 2 and is delayed by 72 °). Therefore, the time-base compressed PCM signal is generated during the T ₃ period of 17) and 18) shown in FIG. This T
CH of time axis compressed PCM signal generated in ₃ periods and timing signal PCM gate (Fig. 11 Fig. 11) which is high level in T ₃ period
-3) and the control signal PCM30 when the above third channel is selected
CH-3 of (Fig. 11) is the recording amplifier 45 shown in Fig. 6.
Is supplied to. This time-base compressed PCM signal is described in the T ₃ period via the switch 50 and the switch 51 that can be switched by the logic output (PCM30 AND PCM gate, ▲ ▼ AND PCM gate) of the timing signal PCM gate and the control signal PCM30. To be done. It is shown in CH-3 of (Fig. 11). ) As described above, during recording in the multi-PCM mode, the phase of the control signal PCM30 that determines the timing of generation of the time-axis compressed PCM signal is shifted by 36 ° according to each channel. -1, CH-2 ... CH-6
The time-base compressed PCM signal generation timing for
The period is T ₁ T ₂ …… T ₆ shown in 17) and 18) of the figure. Further, as shown in FIG. 6, the control signals SC1 and SC2 for switching the switches 50 and 51 of the recording amplifier 45 are also phase-shifted by 36 ° according to each channel, so that the recording of the time-axis compressed PCM signal recorded on the tape 22 is performed. position T _1, T ₂ shown in FIG. 3 in accordance with the respective channels CH1, CH2 ...... CH6, it can be ...... T ₆ region.

In the multi-PCM mode, it is necessary to prevent the PCM audio signal recorded in the already recorded channel from being erased by the video recording signal RECV. Therefore,
In the multi-PCM mode, the switch 100 shown in FIG. 1 is turned off by the mode switching signal Multi H to prevent the video recording signal RECV from being supplied to the recording / reproducing amplifier circuit 16.

Next, a description will be given of the reproduction in the multi PCM mode. What is especially important during playback in this multi-PCM mode is how to handle the pilot signal for ATF tracking control. This is first of all, unlike the video recording / playback mode, to perform ATF servo by using a pilot signal frequency-multiplexed with a time-axis compressed PCM signal, and secondly, as a reproduction pilot signal PBP, which is selected at the time of reproduction. The ATF servo is performed only by the signal recorded on the track of the selected channel. 6th below
This will be described in detail with reference to FIGS. 8, 8 and 12. FIG. 12 is a time chart of main control signals and reproduction signals during reproduction.

In FIG. 6, the time-axis compressed PCM signals reproduced by the heads 20a, 20b are input to the amplifier 5859 via the switches 55, 56 closed to the PB terminal side during reproduction. At this time, the signal reproduced from the head 20a is sufficiently amplified by the amplifier 58 and supplied to the L-side input terminals of the switch 60 and the switch 61. The signal reproduced from the head 20b is fed to the amplifier 5
Sufficiently amplified by 9 and H of switch 60 and switch 61
It is supplied to the side input terminal. The switch 60 is switched by a switch switching signal SC3 (shown in FIG. 12) which is an exclusive OR output of the control signal PCM30 supplied from the multi-channel PCM controller 7 and the mode switching signal Multi H, and the switch 61 is switched. Is a switch switching signal SC4 (first
12) shown in Fig. 28)). Multi PCM
In the mode, since the mode switching signal Multi H is at the high level, the switching signal SC3 of the switch 60 becomes the same as the inverted signal of the switching signal SC4 of the switch 61. still,
The switches 60 and 61 are closed to the L terminal side while the switch switching signals SC3 and SC4 are low, and closed to the H terminal side when the switch switching signals SC3 and SC4 are high. Therefore, the switch 60 and the switch 61 are different to output the same time-base compressed PCM signal, and via the BPF 63
Playback pilot signal PBP supplied to the ATF servo device 15
Is the time-base compressed PCM signal PBPC sent to the PCM signal processing system 12.
It becomes a pilot signal that is frequency-multiplexed with M (shown in FIG. 29).

Time-base compressed PCM signal PBPC supplied to PCM signal processor 12
M undergoes the same processing as in the video recording / playback mode, and is then output as a reproduced audio signal.

Next, regarding the servo system in the multi-PCM mode,
The points different from the video recording / playback mode will be described. First, at the time of recording, as described above, since the video signal is not always input, the vertical synchronization signal SYNC may not be obtained. Therefore, in the multi-PCM mode, switch 68 in FIG.
The reference signal REF30 output from the Hz signal generation circuit 70 is used as a pseudo vertical synchronization signal to determine the rotation phase of the cylinder 23.

During reproduction, the switch 95 of the ATF servo device 15 is closed to the M input terminal side, and the switch 92 of the sample and hold circuit 91 is switched on / off by the timing signal PCM gate supplied from the PCM signal processing device 12. Done. The timing of generation of this timing signal PCM gate is determined by the control signal PCM30 as in the case of recording, and is generated before the rising and falling edges of the control signal PCM30.
It is a period equivalent to 6 °. The time chart of the timing signal PCM gate for each channel is shown in 30) of Fig. 12. The sample and hold of the reproduction pilot signal PBP by this timing signal PCM gate prevents the ATF servo from being disturbed by the unnecessary pilot signal reproduced in the period other than the period corresponding to the selected channel, and the head tracks the track of the selected channel. The scanning is performed accurately and stably.

As described above, in this embodiment, the recording / reproducing timing of the time-base compressed PCM signal is determined, and the phase of the control signal PCM30 for switching the switch of the recording / reproducing amplifier is shifted by 36 ° in accordance with the channel. As a result, it becomes possible to record and reproduce 6-channel audio signals. Then, as a tracking servo, in the video recording / playback mode, the pilot signal frequency-multiplexed with the video signal
In mode, the playback amplifier is switched so that the pilot signal frequency-multiplexed with the time-axis compressed PCM signal is supplied to the ATF servo device, and in the multi-PCM mode, the sample and hold circuit is used, and only the playback pilot signal of the selected channel is used. By performing ATF support in, it is possible to always perform accurate and stable tracking control in both video recording / playback mode and multi-PCM mode. Also, in the multi-PCM mode, the pseudo vertical sync signal is used as the reference signal that determines the rotation phase of the cylinder, so that the PC can be used even if no video signal is input.
M audio signals can be recorded. Further, in the case of the multi-PCM mode, a switch is provided so that the video recording signal RECV is not supplied to the recording amplifier, and it is possible to prevent the already recorded PCM audio signal from being erased. Therefore, one recording / reproducing apparatus can arbitrarily select the recording / reproducing of the audio signal of the video signal + 1 channel and the recording / reproducing of the audio signal of 6 channels, and the usage range thereof is wide.

In a VTR that records and reproduces a video signal and a PCM audio signal, the reproducing amplifier is made into an IC, and as its constitution, a constitution such as a portion 101 surrounded by a dotted line in FIG. 13 is often seen. In such a reproduction amplifier 101, the switch 60,
Since 61 cannot be independently switched, the reproduction pilot signal PBP cannot be supplied to the ATF servo device 15 in the multi-PCM mode as it is, and tracking control cannot be performed. The case where this reproducing amplifier 101 is used will be described below.

In the reproduction amplifier 101 of FIG. 13, the amplifiers 58 and 59 and the switches 60 and 61 are the same as those of the reproduction amplifier 57 of FIG. The amplifier 102 compresses the time base during playback in the video recording / playback mode.
The output level of the playback video signal PBV is made higher than the playback PCM signal level in order to prevent deterioration of the quality of the playback video due to crosstalk from the CM signal output. Amplifier 1
03 makes the level of the pilot signal frequency-multiplexed with the time-base compressed PCM signal PBPCM the same as the level of the pilot signal frequency-multiplexed with the reproduced video signal PBV, and its gain is the same as that of the amplifier 102. Is. The switch 104 is switched via the input terminal 2 by the mode switching signal Multi H supplied from the multi-channel PCM controller 7 shown in FIG. 1, and is switched to the N input terminal side in the video recording / playback mode and M input in the multi PCM mode. It is closed to the terminal side. The control signal PCM30 supplied through the input terminal 26 is the same as the head phase detection signal SW30 in the video recording / reproducing mode and is selected in the multi-PCM mode, as described in FIG. It is a signal obtained by shifting the phase of the head phase detection signal SW30 by 36 ° corresponding to each channel.

With the above configuration, in the video recording / playback mode, the playback video signal PBV is output from the output pin 105 of the playback amplifier IC101,
The video signal processing device 13 shown in FIG.
To the AT shown in FIG. 1 via the switch 104, the BPF 63, and the output terminal 44, which are supplied to the N input terminal side.
It is supplied to the F servo device 15. The reproduction time axis compression PCM signal PBPCM output from the output pin 106 is supplied to the PCM signal processing circuit 12 shown in FIG. 1 via the output terminal 27.

On the other hand, in the multi-PCM mode, the playback time axis compressed PCM signal PB
PCM is output from output pin 106 of playback amplifier IC101,
The switch 1 is supplied to the PCM signal processing device 12 through the output terminal 27 and is closed to the amplifier 103 and the M input terminal side.
It is supplied to the ATF servo device 15 via 04, BPF 63 and output terminal 44. Video signal processor 13 and PCM signal processor
12 and the reproduced video signal P supplied to the ATF servo device 15, respectively.
BV, playback PCM signal PBPCM, and playback pilot signal PBP are
The processing described above is performed for each.

Therefore, as shown in FIG. 13, by providing the amplifier 103 and the switch 104, the required reproduction pilot signal can be always supplied to the ATF servo device at an optimum level, and stable tracking control can be performed.

〔The invention's effect〕

According to the present invention, it is possible to record and reproduce a video signal and an audio signal of one channel, and record and reproduce an audio signal of a plurality of channels with one VTR. With respect to the above, since the tracking control can be preferentially performed, it is possible to reproduce high-quality audio with a low PCM error rate.

[Brief description of drawings]

FIG. 1 is a block diagram of a VTR using the present invention, and FIGS. 2 and 3 are diagrams showing the tape pattern and the positional relationship between the tape and the cylinder in the video recording / reproducing mode and the multi-PCM mode, respectively. Is a block diagram of the PCM signal processor,
FIG. 5 is a time chart of main signals in the PCM signal processing device, FIG. 6 is a block diagram of a recording / reproducing amplifier circuit,
FIG. 7 is a time chart of main signals in the video recording / playback mode, FIG. 8 is a block diagram of a servo device, FIG. 9 is a diagram showing an example of a concrete circuit configuration of a multi-channel PCM controller, and FIG. 10 is a control signal. The PCM30 time chart, FIG. 11 and FIG. 12 are time charts of main signals during recording and reproduction in the multi-PCM mode, respectively.
The figure is a block diagram of a reproducing amplifier system. 7 …… Multi-channel PCM controller 12 …… PCM signal processor 13 …… Video signal processor 14 …… Main servo device 15 …… ATF servo device 16 …… Record / playback amplifier circuit 50,51,60,61 …… Switch 91 …… Sample and hold circuit 68,95 …… Switch 9 …… 6-phase PCM30 generation circuit 8 …… Channel selector 10 …… Switch 104 …… Switch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Akira Shibata Akira Shibata, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd. Home Appliances Research Laboratory, Hitachi, Ltd. (72) Inventor Katsuyuki Watanabe 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa (56) References JP-A-58-222402 (JP, A) JP-A-61-150179 (JP, A)

Claims (2)

[Claims] 1. A magnetic tape is helically scanned by first and second rotary heads, and an oblique track formed on the magnetic tape is divided into an image area and an overlap area extending from the helical tape by the helical scanning. , A first recording mode for recording a video signal in the video region and a time-axis-compressed pulse code modulated audio signal in the overlap region, and N for the video region of the diagonal track.
A second recording mode in which the pulse code modulated audio signal is recorded in any one of the overlap area and the N partial areas. In any of the first and second recording modes, in the information signal recording / reproducing apparatus in which a tracking pilot signal is multiplexed and recorded on the video signal and the pulse code modulated audio signal recorded on the diagonal track, The first to which the reproduction signal from the rotary head is supplied
Input terminal, a second input terminal to which the reproduction signal from the second rotary head is supplied, and one of the reproduction signals supplied to the first and second input terminals are selected. Outputting first and second switches, a video signal processing circuit for processing a video signal of the reproduction signal output from the output terminal of the first switch, and outputting from the output terminal of the second switch Audio signal processing circuit for processing a pulse code modulated audio signal of the reproduced signal to be reproduced, and a pilot signal processing circuit for processing the tracking pilot signal of the reproduced signal output from the output terminal of the first switch And a first control signal having a frequency that is phase-synchronized with the rotation of the rotary head and is equal to the rotation frequency, and second to N + 1th control signals that are sequentially out of phase by 180 degrees / N from the first control signal. And And a control signal generating means for generating the magnetic tape recorded in the first recording mode, for controlling the switching of the first switch by the first control signal, and the first control signal. The second switch is controlled to be switched by an inversion signal of, and when reproducing the magnetic tape recorded in the second recording mode, the overlap area of the oblique track and the N partial areas are recorded. By specifying any one of the above, the first
A control means for controlling switching between the first switch and the second switch by an inversion signal of the control signal corresponding to the designated area of the (N + 1) th control signal, and the first recording When reproducing the magnetic tape recorded in the mode, the output terminal of the second switch outputs the pulse code modulated audio signal reproduced from the overlap area of the oblique track, and the first switch of the first switch outputs. A video signal reproduced from the video area of the diagonal track is output from the output terminal, the tracking pilot signal multiplexed on the video signal is processed by the pilot signal processing circuit, and in the second recording mode. When reproducing the recorded magnetic tape, the specified area of the oblique track is output from the respective output terminals of the first and second switches. From the output terminal of the first switch, the tracking pilot signal multiplexed with the pulse code modulated audio signal is processed by the pilot signal processing circuit. An information signal recording / reproducing apparatus having the above-mentioned structure. 2. A magnetic tape is helically scanned by the first and second rotary heads, and an oblique track formed on the magnetic tape by the helical scanning is divided into an image area and an overlap area extending therefrom. A first recording mode in which a video signal is recorded in the video area and a time-axis-compressed pulse code modulated audio signal is recorded in the overlap area, and the video area of the diagonal track is recorded in N
A second recording mode in which the pulse code modulated audio signal is recorded in any one of the overlap area and the N partial areas. In any of the first and second recording modes, in the information signal recording / reproducing apparatus in which a tracking pilot signal is multiplexed and recorded on the video signal and the pulse code modulated audio signal recorded on the diagonal track, The first to which the reproduction signal from the rotary head is supplied
Input terminal, a second input terminal to which the reproduction signal from the second rotary head is supplied, and one of the reproduction signals supplied to the first and second input terminals are selected. Output first and second switches, a first amplifier for amplifying the reproduction signal output from the output terminal of the first switch to a predetermined level, and a reproduction signal output from the first amplifier A video signal processing circuit for processing the video signal of the second switch, an audio signal processing circuit for processing the pulse code modulated audio signal of the reproduction signal output from the output terminal of the second switch, and the second switch A second amplifier for amplifying a reproduction signal output from the output terminal of the rotary amplifier to a predetermined level, a first control signal having a frequency that is phase-synchronized with the rotation of the rotary head and equal to a rotation frequency, 180 degree / N from signal Control signal generating means for generating the second to (N + 1) th control signals which are out of phase with each other, and at the time of reproducing the magnetic tape recorded in the first recording mode, the first control signal is used to reproduce the first 1 switch is controlled, and the second switch is controlled by an inverted signal of the first control signal to reproduce the magnetic tape recorded in the second recording mode. By designating one of the overlap region and the N partial regions of
Control for switching the first switch with a control signal corresponding to the designated area of the (N + 1) th control signal, and controlling the second switch with a signal in an inverse relationship with the control signal. Means for reproducing the magnetic tape recorded in the first recording mode, the reproducing signal output from the first amplifier is selected, and the magnetic tape recorded in the second recording mode is selected. During reproduction, a third switch for selecting the reproduction signal output from the second amplifier, and a pilot signal for processing the tracking pilot signal of the reproduction signals selected by the third switch A processing circuit is used, and as the first and second switches, the first amplifier, and the control means, one existing integrated circuit incorporating these is used, and the second amplifier is With the same gain as the first amplifier, the levels of the tracking pilot signals in the reproduction signals output from the first and second amplifiers are made equal, and recording is performed in the first recording mode. When the magnetic tape is reproduced, the pulse code modulated audio signal is output from the output terminal of the second switch, the video signal is output from the output terminal of the first switch, and the video signal is multiplexed to the video signal. The tracking pilot signal thus processed is processed by the pilot signal processing circuit, and when the magnetic tape recorded in the second recording mode is reproduced, the pulse code outputted from the output terminal of the second switch. The tracking pilot signal multiplexed with the modulated voice signal is processed by the pilot signal processing circuit. Information signal recording / reproducing device.