JPS61167288A - Video tape recorder - Google Patents

Abstract

PURPOSE:To reproduce any kind of tape by providing a means for extracting tracking control signals from reproduction signals, producing identification signals on the basis of the extracted signals and switching the reproducing circuit on the basis of the identification signals. CONSTITUTION:The reproducing signals A, B picked up by magnetic heads 25a, 25b from a magnetic tape 1 and amplified (8, 9) are switched over by a control signal F from a controller CT35 via. a changeover switch SW10, 11. The output C from the SW10 is inputted via. a video signal reproducing and processing circuit 21, BPF18 and SW38 to an automatic track finding ATF processing circuit 22 and a system identification circuit 40. SW38 is connected to the V side by controlling CT35. The output signal D of SW11 is inputted to a PCM signal reproducing and processing circuit 32. In the circuit 22, control signals are outputted to a servo processing circuit 30 for performing tracking servo. A circuit 40 identifies the NTSC/CCIR system to switch over the pilot frequency of a pilot generator 31 corresponding to the identification and the circuits of the respective parts are switched to corresponding systems.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention is a helical scan type videotape.

This video cheapo is related to recorders and is especially suitable for playing back time-base compressed PCM audio signals.

It's Korg. 2. [Background of the Invention] Helical scan type video tape recorder 01 As an example, there is a home video tape recorder called 8 mm video standard whose tape pattern is shown in FIG.

In FIG. 12, 1 is a video tape, 2 is a video track on which a video signal is recorded, 6 is a first option track, and 4 is a second option.

track, 5 is the direction that the rotating head traces.

Arrows 6 indicate the running direction of the videotape. .

The arrow 7 indicates a signal that has been converted into a PCM signal (an audio signal) and further compressed the time axis to about 1/6 and recorded.

It is a truck that can be used.

In FIG. 12, θ1. θ2. θ3. θ4 is each rotating cylinder.

Show the winding angle of the videotape wrapped around.

θ1, 5° in θ4, 180° in θ2, so in θ5
It is a. Here, θ2 corresponds to the period in which the video signal is recorded, θ3 corresponds to the period in which the audio signal is recorded, and θ1. θ4 is a margin to ensure compatibility (hereinafter, the tape pattern shown in FIG. 10).

The recording method is called video signal recording mode. ). Therefore, when used for recording only audio signals, the area on the videotape used for recording is only the area shown by 7 in FIG.

Otape usage efficiency was poor. 5 A method to improve this is shown in Fig. 15.

In particular, video track 2 is divided into five areas, B and -F.

12 in the same way as in FIG. 7 (in FIG. 13).

(corresponding to area A) Record the time axis compressed P CM signal.

There is a tape recording method (hereinafter referred to as the tape shown in Figure 11).

The pattern recording method is Marusen P-CM recording mode.

It is called. ). (Unexamined Japanese Patent Publication No. 58-222402) This method.

Now, the audio signal is written six times as compared to the method shown in Figure 12.

can be recorded. Multi-PCM description mentioned above.

The recording mode allows the video tape recorder to be used in a wide range of applications, including the audio field.

However, the video tape recorder operates based on a synchronization signal obtained from a video signal.

Because of this, there are two systems: NTSC and CCI R, and the NTSC system uses 3oHz and CCI R.
As the CIR system uses 25Hz as the standard, there is no compatibility between the two systems. -As a result, unlike television systems, it is not possible to take full advantage of the audio system's advantage that monitor systems are common throughout the world.

Or soft tape, which is compatible with two methods.

This has many disadvantages, such as the need for

There was a problem with this.

[Object of the invention] - (The object of the invention is to improve the NTSC system and CCI.

Plays tapes recorded with either R system.

A possible video tape recorder is obtained.

[Summary of the invention]

In order to achieve the above object, the present invention uses two methods for identifying a tape recording system using the reproduction frequency of a pilot signal for a trough l-king servo and a method for identifying a tape recording system using a PCM signal. This automatically switches the tape recorder's playback system.

-O ・　5　・ [Embodiments of the invention] The video tape recorder of the present invention is illustrated below.

This will be explained using examples shown below. FIG. 1 shows an example in which the present invention is applied to a playback system of a video tape recorder (V-TR) based on the 8 mm video standard.゛・VTR shown in Figure 1
It can play back tapes recorded in either NTSC or CC technology, and is also compatible with multi-PCM.

First, the case of reproducing the tape pattern shown in FIG. 12, that is, the 1° tape recorded in the video signal recording mode, will be described. .

The reproduction signal extracted from the magnetic tape 1 by the rotary head 23α or 254° is sent to a preamplifier 8.

or 9, resulting in the results shown in Fig. 2 A and B. Increase.

The widened reproduction signals A and B are sent from the controller 35.

Selector switch (SW) 1 is activated by the control signal (F1 in Figure 2).
11.11. One of the outputs of the 5W10 (Fig. 2C) is sent to the video signal reproduction processing system 21, and the other is sent to the bandpass filter (BP) for extracting the FM audio signal.
F) 18, one is 5W58□.

, 4.

Through the automatic track finding processing circuit (ATF processing circuit) 22 and N・TSC/C
System identification circuit 4 for identifying CIR systems
Enter 0. Note that since a tape recorded in the video signal i8 recording mode is being played back, the 5W58 is connected to the V side according to a command from the controller 35. S'W
The output of 11 (FIG. 2D) is sent to a PCM signal recirculation processing circuit 62. The reproduction signal input to the video/image signal reproduction processing system 21 is as follows.

The filter block 12 converts the low frequency converted chromaticity signal and F! ,1
After being separated and extracted into M-modulation modulation depth signals, it is used as a video signal.

The signal processing circuit 15 is composed of a signal processing circuit 15 and an oscillation circuit 15.

FM demodulation of the luminance signal in the video signal reproduction processing circuit.

Then, the chromaticity signal is reconverted and the demodulated video signal is generated.

The signal is output from the output terminal 14. Input to BPF18, -
The reproduced signal is only the FM audio signal.

After being extracted, the FM audio processing circuit (A.

PM processing) is FM demodulated into an audio signal at step 19.

It is output from the output end 20. In the ATF processing circuit 22.

is a replay signal to perform tracking servo. ,.

The four-wave pilot signal is extracted from the 4th frequency, and the reproduced pilot signal obtained from both adjacent tracks is reproduced.

A control signal is output to the servo processing circuit 50' so that the signals are at the same level.

An example of a specific circuit configuration of the ATF processing circuit 22 and the pilot signal generation circuit 531 is shown in FIG. In FIG. 3, the reproduction signal from the magnetic tape 1 inputted from the input terminal 72 (FIG. 2, C in the video signal recording mode, FIG. 2, D in the multi-PCM mode) is input.

A 4-frequency 1° regenerated pilot signal (f at N'l'SC, = 103
To &.

f, -119KHz, f, 5165KHz, f
149KT(z) out of 4.

The frequency is changed by extracting the signal and multiplying it by the output signal of the pilot signal generation circuit 31° in a multiplier 74.

Perform the exchange. From the output of the multiplier 74, BPF75 and 77□
.

using approximately 16 KHz and approximately 47 KH! proportional to the pilot signal levels obtained from both adjacent tracks. The components are separated and extracted, and the respective output levels are detected by envelope detection circuits 76 and 78. The detected output is sent to the comparator 7
9, and when playing the video signal, use LPF'84 and 5W85.

The signal is then sent to the servo processing circuit 50 from the output end 86.

It will be done. When playing in multi-PCM mode.

A sample-and-hold circuit consisting of a 5W80 and a capacitor 81 outputs the output of the comparator 79 only for the section of the track to be reproduced - for example, the section corresponding to B in Fig. 13. Extract, ・Buffer 82 and LPF
85 and 5W85 to the servo/processing circuit 50. It is sent out from the output end 86.

In response to the received signal, the servo circuit 30 outputs the cabs.

The output of the comparator 79 is controlled by controlling the tongue motor 29.

Tracking servo is performed to make it zero.

Ru. Here, the signal that controls 5Wao is a PCM signal.

A gate pulse signal generated by the oldest generation processing circuit 62.

(Figure 2G), and the PCM signal reproduction processing circuit 3
2 is generated from the channel select signal shown in FIG. 2 CH.

Next K1. The pilot signal generation circuit 31 will be explained. Oscillation circuit 65: 5.95M in N'I'8C system
Hz, and is configured to provide an oscillation output of 5.86 MHz when using a CCI system.

It is switched by the output signal of the system identification circuit 40. The output signal of this oscillation circuit 65 is passed through branchers 66 to 69 to 158.・1
150 ”156 # Pilot by dividing the frequency by 1/40.

Signals f, , f2. f, , f, are obtained. These pilot signals f, ~f, 5 are output by the output switching circuit 70.
The servo processing circuit 30 receives input from the input/output end 71.
・fl, f2 . f, , f are sequentially switched and output.・Here, the head switching signal is the magnet 24α1 No. 1 attached to the cylinder with a 1 degree angle and the pickup head.

It is created based on the signal obtained from No. 25. .

The servo processing circuit 60 uses the above-mentioned magnet.

24a r 4 and the pickup head 25.

Compare the signal with a reference signal within the servo processing circuit 30.

Then, the rotation speed of the cylinder motor 26 becomes constant.

It is controlled as follows. In addition, capstan motor.

- The motor 29 is connected to the FG2B attached to the motor.

The rotational speed is kept constant using the output of the rotational speed signal generator consisting of the backup head 27, and tracking is performed using the output signal of the ATF 2°.8.processing circuit 22.

In the PCM signal reproduction processing circuit 52, the PCM signal is regenerated.

After waveform equalization and data identification of the raw signal, P/CM demodulation is performed and demodulated audio signals are output from output terminals 55 and 54.

A specific example of the PCM signal reproduction processing circuit 52 is shown in FIG. In FIG. 4, the reproduced signal inputted from the input terminal 63 is sent to a waveform equalization circuit 49 in which code quantization, interference, etc. are removed, and then one is sent to the strobe circuit.

one to a doubler circuit 50 and a phase comparator 511;
．． .

and a filter 52 and a voltage controlled oscillator (VCO) 55.

It is output to the clock regeneration PLL circuit consisting of.

It will be done. The strobe circuit 54 reproduces the clock.

Waveform generated by clock reproduced by PLL circuit.

Data is reproduced from the output signal of the equalization circuit 49.

Regenerated data that is the output of strobe circuit 54.

The signal is input to the PCM processor 56°K together with the reproduced clock, and the PCM processor 56 performs error correction, decoding, time axis expansion, etc. Ella.

-Perform operations such as correction, decoding, and time axis expansion. , 1 random access memory (RAM).

55 and a master clock generation circuit 57 are used.

In addition, the PCM7' rosette operates at 5oHz% in the NTSC system and 25H2 in the CCIR system (CH1 in Figure 2).
For O and CCIR, input from input terminal 135.

The frequency division circuit (not shown) in the PCM processor 56 is switched by the input control signal. The reference signal (CHt in FIG. 2) is input from the input terminal 64 to the PCM processor 56 and master clock generation circuit 57.

Decoded and time axis pushed by PCM processor 56.

The lengthened digital signal is a digital analyzer.

Analog signal at log converter (D/A) 59, ie.

In other words, it is returned to the audio signal. D/A59 output signal woA.

Unnecessary band components were removed with LPF60.61.

The dynamic range is compressed during recording.

Original Dyna in Noise Reduction (Ha) 62.

[from the output ends 55 and 54].

It is output as a playback audio signal. In addition, multi 2゜PC
When in M mode, it corresponds to each track.

The reference signal (CH1 to CH6 in Figure 2) is the controller 3.
5 through the input terminal 64. Furthermore, gate pulses (G1 to G5 in FIG. 2) corresponding to each track are output from the output terminal 152 from the PCM processor 56,
The signal is sent to the ATF processing circuit 22 and the system identification/discrimination port.

By the way, the video signal reproduction processing system 21 and the PC.

M signal regeneration processing circuit 52 and pilot signal generation port.

The path 31 and the servo processing circuit '50 are the NT8C system,
.

and CCI system signal processing are different.

Ru. For example, the video signal reproduction processing system 21 uses chromaticity signals.

The color burst signal frequency for signal processing is NT.

5.58MHz with SC 4.45MHz with %CCI
There is a te.

And remove crosstalk from adjacent tracks.

The chromaticity signal processing system for this purpose is called a phase invert method (PI method) in NT8C, and a phase shift method (P8 method) in CCI R. The PCM signal reproduction processing circuit 52 and the servo processing circuit 50 operate as a single signal based on 30Hz in NT8C and 25H2 in CCIR. Also a pilot.

When the reference frequency of the signal generation circuit 31 is NTSC, it is 5.95.
MHz % CCI R is 5.86 M) Iz.
.

Therefore, it is necessary to determine whether the tape being played back is an NTSCfi system tape or a CCIR system tape, and to switch the signal processing circuit.

In this embodiment, the pilot signal frequency in the reproduced signal is NT.

Tapes recorded with the SC system are transferred to the CCIR system.

When played on a system and recorded on a CCI R system.

The recorded tape was played back on the NT8C system.

It uses different things depending on the situation. A specific example will be described below with reference to FIG. 6. 4-frequency pilot signal - NTS to perform 1° tracking servo
For C, f, medium 102.55KH7:.

118.95KHz in f2, 165.20K in f
It is assumed that 148.69° KHz is used in H2 and f4. NT8C system.

The CCI system uses the tapes recorded by the CCI system. ,.

, 12° and when a tape recorded with the CCIR system is played back with the NT8C system.

The frequency of the regenerated pilot signal is cylinder rotation.

Since the numbers are different from 25Hz (CCIR) and 50Hz (HT8C), the values are as shown in Table 1.

In FIG. 5, the system identification circuit 40 is turned on.

117-center frequency 85.55KHz, Q =
20 -2° peak detection circuits 107, 118, hold circuits 10B, '119, level identification circuits 109, 1
20 8W114.

It is composed of a voltage source (VB) 115 and a state determination circuit 41.

It is. Now, the video tape recorder shown in Figure 1.

Suppose that this video tape recorder is operating as a CCIR system; if this video tape recorder is used to play back a tape recorded in the video signal recording mode using the NT8C system,
The reproduction signal from the magnetic tape 1 inputted from the input terminal 72 is the output signal of S.Wlo shown in the second diagram, and is sent to the tank circuits 106 and 117+.

Enter K. Here, in the reproduced signal (FIG. 2D).

The frequency of the pilot signal is shown in Figure 1 above.

Since the frequency is the same, it is probably the tank circuit 117.

The pilot signals of f, are extracted, but tan.

No pilot signal is extracted from the circuit 106.
'O The outputs of the tank circuits 10'6 and 117 are peak detected.

The wave is detected by the wave circuits 107 and 118, and the hold circuit 1
After passing through 08 and 119, the pilot signals of the tank circuits 106 and 117 are sent to the level identification circuit 109 and 120. .

The presence or absence of the number (-1 茅.l) is identified. Therefore, in the above case, the pilot is busy from the tank circuit 117.

Since the signal is extracted, the level identification circuit 120
is output, and 0 is output from the level discrimination circuit 109.

Output. Note that the 8W 114 is operated by the control signal indicating the multi-PCM mode input from the input terminal 112, and is connected to V@ since it is in the video signal recording mode as described above. lead circuit 108
, 119 are DC voltage sources.

It becomes constant at VB and is always in a conductive state. 1(,
The outputs of the level discrimination circuits 109 and 120 are statuses.

input to the discrimination circuit 41 and according to the output signal.

The level identification circuit 109 discriminates whether the signal on the reproduced tape is an NTSC system or a CC1IR system, and outputs an NT, SC system time signal, and a CCIR system 11° signal from an output terminal 115.

120 and the output signal of the state determination circuit 41.

The relationship is shown in Table 2.

Therefore, in the above example, the NT8C system.

0 is output from the output terminal 115 so as to switch.

(−・15・Table 2) According to the output signal (0, A, t) of the output terminal 115, the video/image signal reproduction processing system 21 outputs the chromaticity signal as described above.

5.58 Mkb (N T 8 C) and 4.45 MHz (.

(CCIR) oscillation crystals 16 and 17 are switched.

Well, the inside of the busy video signal processing circuit 15 is the PI side.

Disconnect between formula (NT8C) and ps method (CCIR,).

Do something like change it. In the servo processing circuit 50, N.

TSCSC quasi-standard signal 5oHzcc 20Hz when I R
The oscillation frequency of the reference oscillation circuit (not shown) is set so that the oscillation frequency is 1°.

The number and frequency dividing circuit (not shown) are switched.

In the PCM signal reproduction processing circuit 32, the frequency is 5 OHZ at NTSC.
During pCCIR, the system operates using 25 Hz as a reference signal, so 21° in the PCM processor 56,
Switch the 16° frequency divider circuit (not shown). In addition, in the pilot signal generation circuit 51, the oscillation crystals 121 and 122 of the reference oscillation circuit 65 are switched to
5MHz when using CCI R, 5.86MHz when using CCI R.
So busy.

Next, in the video tape recorder shown in FIG. 1, the tape pattern shown in FIG.
CM recording mode was busy and was recorded.

- System identification port when playing a tape.

The operation of the path 40 will be explained using FIG. 1. .

[Recorded Qi] in multi-PCM recording mode.

If you want to play back the tape, use the command from the controller 35.

From 8. W2B is connected to the M side. Also, 8W-1o
.

11 is switched in Fig. 2 F1s F2, and Fig. 15 B
M+.

When reproducing area F, switching is made with F2. 1°, therefore, the output signal of 5W11 (D1 to I in FIG. 2) is input to the ATF processing circuit 22 and the Systella identification circuit 40. Tank circuits 106 and 117 extract pilot signals from the reproduced signals D1 to D6 in FIG. 2 inputted from input terminal 72. For example, VTR.

is operating as an NTSC system, and the tape you are trying to play back was recorded in the CCIR system.
) are as shown in Table 1, and the frequencies and numbers of pilot signals in tank circuit 106. No pilot signal is extracted from fi117. The outputs of the processing circuits 106 and 117 are sent to the peak detection circuit 107. .

After detection at 118, the track area to be reproduced corresponds to, for example, B in FIG.

1. Extract only the signal in the D2 signal section of FIG. 2.

In order to do so, the hold circuits 108 and 119 hold the ho.

Execute the file processing. The hold circuit 1oa, 119 is.

It operates with the guest pulse signal shown in FIG. 2 02 inputted from the input terminal 111.

Hold circuits 1.08 and 119 (7) Outputs are output from level identification circuits 109 and 120 to tank circuits 106 and 1
17 K- (Identifies the presence or absence of the extracted pilot signal, and the level identification circuits 109 and 120 output "'1#" if there is a pilot signal, and "0" if there is no pilot signal. In the above example, 1. Tank circuit 106 , 117, the level identification circuit 109, 1
Both outputs at 20° are *0'. In addition, since the operation of the state determination circuit 41° is as shown in Table 2, the output terminal 11
From 5 onwards, I was instructed to change the CCI system.

1 is output.

As explained above, in multi-PCM mode, the pilot signal for only the recorded track section to be played back is used, and the chip to be played back is recorded in either the NTSC system or the CCIR system. Identifies what was done.

FIG. 5 shows another specific example of the system identification circuit 40.

shows. In FIG. 5, the system identification circuit 40° has a tank circuit 123-center frequency of 195 KHz.

Q=20- and tank circuit 128-center circumference.

Wave number 85.55KHz, Q = 20-, peak detection circuits 1-124, 129 and hold circuit 125,
150 and level.

Identification circuit 126, 161 5W 114 Voltage source (VB)
.

113 and B, 8 flips 70 knobs (R, S -F', F
, ) 127°. Here, a video cheap 4 coder is operating as a CCIR system. , replaying tapes recorded on the NT8C system on January 19th.

When it occurs, the pilot signal frequency in the regenerated signal.

is the value shown in Table 1. Therefore, the reproduction signal input from the input terminal 72' is output from the tank circuit 128.

A pilot signal corresponding to fl is extracted, but no pilot signal is extracted from the 5-tank circuit 123.

Furthermore, the outputs of the tank circuits 125 and 128 are detected by peak detection circuits 124 and 129, and then passed through hold circuits 125 and 150 (level detection).

It is input to separate routes 126 and 151. Level identification circuit 1
0126, 151, tank circuits 125, 1, respectively
28?

identify the presence or absence of a pilot signal extracted from the

11' if there is a pilot signal, if not.

Outputs 5ON. Therefore, in the above case, level awareness.

The output of the separate path 126 becomes 10', the 15 output of the level discrimination circuit 151 becomes 1#, resets R8-F, F, 127, outputs 0 from the output terminal 110, and outputs N for each block.

Switch to TSC system. By the way, video team.

The precoder is operating in the NTSC system.

Sometimes tapes were recorded using the CCIR system. .

・20.

, the pilot signal is output only from the tank circuit 123 as shown in Table 1, so the output of the level discrimination circuit 126 becomes ``1N'', the output of the level discrimination circuit 161 becomes ``0#'', and RS - Set F, F, ・'1'
is output from the output terminal 110. The nine output signals from this output terminal 110 cause each block to be CCIR scanned.

Switch to stem.

Also, the operating system of the videotape recorder.

and the signal format of the tape you are trying to play.

are the same, the level identification circuit 126.1519
The outputs are both 10'', the outputs of R8-F, F, and 127.

There is no change in the status, so switching the system is a row.

I can't get used to it.

Above are the outputs of the level identification circuits 126 and 151 and R18.
Table 3 summarizes the relationship between the outputs of −F, F, and 127.

Here, the hold circuits 125 and 150 are shown in FIG.

Oh, the one I explained is the same as the multi-PC'M
When reproducing a tape recorded in the V.5 recording mode, only the pilot signal of the track to be reproduced is used, so only the track section to be reproduced is in a conductive state. These hold/hold circuits 125, 13
The control signal of 0 is input from the input terminal 111.
The signal is as shown in ~G5.
5 Table 3 FIG. 6 shows another specific example of the system identification circuit 40.

shows. In Figure 6, system identification circuit 40° is tank circuit 137 - center frequency 85.55 KHz.
.

Q=20- and tank circuit 138-center frequency 164
output, Q = 20-, tank circuit 139 - output to center frequency 195, Q = 20-, peak detection circuit 140,
141, 142 and hold circuits 143, 144, 1
45, a level comparator 146, a state determining circuit 2, 147, 5W, 114, and a voltage source (VB) 113.

It is. Here, the video channel shown in FIG.

The precoder operates as a CCI R system.

Qi recorded with the NTSC system at the time.

When you play back the pilot signal in the playback signal.

The frequencies are the values shown in Table 1. Therefore, enter.

The tank circuit 137 extracts the pilot signal f from the reproduction signal inputted from the power end 72, and the tank circuit 158 and the tank circuit 159 extract the pilot signal.

Although it does not change, Soi 1,4 components around 164 KHz and 195 KHz are extracted. Tank circuit 157, 15
8.

The output of 159 is the peak detection circuit 140, 141, 1
．． ! After the wave is detected in 12, a hold circuit 145,
Enter 144°145. Hold circuit 143.14
The outputs of 4 and 145 are sent to a level comparator 146 at three levels P(-).

- hold circuit 143), Q (hold circuit 144), R (
The hold circuit 145) is compared to determine the level ratio.

The comparator 146 outputs a signal indicating the maximum value of P, Q, and R to the state determining circuit 147. Status determination circuit 1
At 47, the output of the level comparator 146 is determined by the NT8C and CCI detection system.

If you have an NT8C system, set the CCI to 0.

In the case of the 几 system, 51'' is output from the output end 148.

Relationship between level comparator 146 and state determination circuit 147.

is as shown in Table 4. Table 5
4. Therefore, in the above example, the level comparator 146 represents y.

Since it is output to the status determination circuit 147, it is output from Table 4.

``OI'' is output from the terminal 148, and in accordance with this output signal, each block in FIG. Same as the one.

Yes, recorded in the most likely PCM recording mode.゛When playing a tape, K, trying to play, 24.

0 to use only the pilot signal of the rack, only the track section to be played is in a conductive state.

Become. This hold circuit 145, 144, 145 control.

The control signal is input from the input terminal 111 in FIG.

This is a signal as shown in G5.

In the above, the reproduction frequency of the pilot signal is used.

Although the system identification method has been described using three examples, other methods, such as the center frequency of the tank circuit, may also be used.

How to set the number to 164KHz and 195KHz and the center circumference.

A method using one tank circuit with a wave number of 165 KHz.

There are many possible methods, but what is the method that uses the reproduction frequency of the pilot signal?

It is clear that the configuration may be used.

Next, another embodiment of the present invention is shown in No. 7-.

The VTR shown in FIG. 7 has the same functions as the VTR shown in FIG. 1, and the same circuits are denoted by the same numbers, and the explanation thereof will be omitted. In FIG.

The difference from Figure 1 is the text that is about to be played.

- The reproduced PCM signal is used to identify which system, NTSC or CCIR, was used to record the disc. In other words, PCM faith.

The PCM signal obtained from the oldest generation processing circuit 32.

- using the pulse signal (01-Gs in Fig. 2).

The system identification circuit 44 is reproducing the Qi.

The NT8C system and the CCIR system.

Identify and identify which system was recorded.

According to the results, the servo processing circuit 30 and the oldest video signal.

Raw processing system 21, pilot signal generation circuit 51, and PC.

M signal reproduction processing circuit 32 is NTSC or CC0IR
This can be switched to the system. FIG. 8 shows a specific configuration example of the 1° system identification circuit 44.

Shown below. In FIG. 8, input is made from the input terminal 63.

The reproduced PCM signals (01 to Gs in FIG. 2) are subjected to a waveform equalization circuit 49 in which code amount interference and the like are removed. .

One of the output signals of the waveform equalization circuit 49 is input to the stroke circuit 54, and one is input to the gate circuit 87 forming the system identification circuit 44. Here, as shown in Figure 9, the PCM signal of the 8mm video standard is composed of five parts, which are roughly divided into a preamble part, a data part, and a postamble part.The preamble part is used for data reproduction. do.

1 data to make it easier to reproduce the clock.

5.79 MHz in the NTSC system, CC
IR.

The system records a 5.75MHz signal.

An example of a specific circuit configuration shown in FIG. 8 identifies the reproduction frequency of the signal of this preamble section.

So, is it the NT8C system or the CCIR system?

This is a method of identifying In the gate circuit 87, the top.

Of the output signals of the waveform equalization circuit 49, FIG.

Extract only the part corresponding to the preamble part shown.

put out Preamplifier extracted by gate circuit 87.

The signal from the input section is input to tank circuits 88 and 95. evening.

The link circuit 88 has a center frequency of 4.85 MHz, Q
=20, tank circuit 93 center frequency 489MHz
, Q = 20.

By the way, as mentioned above, the frequency of the signal in the preamble part is 5.79 MHz in the KNT8C system and 5.75 MHz in the CCIR system, so it does not matter whether the video tape recorder (position V) operates in the NTSC system or the CCIR system. Then, from 27 degrees or K, the reproduced signal station/wave number of the preamble portion becomes the values shown in Table 5.

Table 5 So, the VTR operated on the N'l'8C system.

The tape I am trying to play is CCII'L system.

Assuming that time K"C is recorded, from Table 5, evening.

The link circuit 95 extracts the preamble signal.

Therefore, no signal can be obtained from the tank circuit 88. evening.

The outputs of the link circuits 88 and 95 are transmitted to the peak detection circuits 89 and 95, respectively.
After being detected at 94°, the detection output is sent to a hold circuit.

Only the period corresponding to the preamble part in 90 and 95,
.

Extracted. The outputs of the hold circuits 90 , 95 are detected by level discrimination circuits 91 , 96 to determine the presence or absence of the output signals of the tank circuits 88 , 95 . ．． 96
outputs 1 when the preamplifier signal is extracted by the tank circuits 88 and 95, and outputs OI when the signal is not extracted. Level identification circuit 91. ,,96 outputs.

R8-F, F, 127 tries to play it manually.

Chi 1 is NT8C system or CCIR system.

The result is output from the output terminal 97.

It will be done. The output of the level discrimination circuits 91', 96 and R,8
The relationship between the output of -F and 5F is as shown in Table 6,
N.

0 for TSC system, 0 for CCIf’L system.

1 is output from the output terminal 97.

In response to this output signal, each block shown in FIG. 7 is switched to the CCI system.

Note that the gate circuit 87 and hold circuits 90 and 95 are connected to P
A timing pulse generator that generates a timing pulse having a pulse width of a period corresponding to the preamplifier partial pressure by inputting the gate signal (01 to Gs in FIG. 2) output from the CM processor 56. It operates based on the output signal of the circuit 134. .

Note that the input signal to the gate circuit 87 may be a reproduced signal input from the input terminal 563. System knowledge.

Another specific example of the configuration of the separate circuit 44 is shown in FIG. 10. In FIG. 10, the same operating circuits as in FIG. 8 are given the same numbers. Tank circuit 135 has a center frequency.

It has a characteristic of number 5.77 MHz%Q=20. input.

A reproduced PCM signal input from the end 63 (DI in FIG. 2).

~D6) are cases forming the system identification circuit 44.

input to the output circuit 87. For the gate circuit 87, the above.

Of the output signal of the waveform equalization circuit 49, only the portion corresponding to the preamble portion as shown in FIG. 9 is extracted 1.1. The preamble portion signal extracted by the gate circuit 87 is input to the tank circuit 155.

Now, the VTR operates as an NTSC system.

Assuming that the tape to be played back is recorded using the CCIR system, no signal can be extracted from the tank circuit 155 as shown in Table 5. After the output of the tank circuit 135 is detected by a peak detection circuit 89, the detected output is extracted by a hold circuit 9o only for a period corresponding to the preamble section K. hold circuit.

The output of 90 is sent to the tank circuit 9o by the level identification circuit 91.
The presence or absence of the output signal is identified by the level identification circuit.

91 is the tank circuit 90 busy and the preamble section signal.

Outputs 1 when extracted, and 10' when not extracted.

Output. The output of the level identification circuit 91 is used to determine the state.

Input circuit 136&C, and the tape to be played is 1,
1. Determine whether it is an NTSC system or a CCIR system.

be done. The operation of the state determination circuit 136 is shown in Table 7.

As expected, when the NT8C system is ""0#, CCI.

In the R system, '1#' is output from the output terminal 92. .

Table 7 15.31
.

In the above example, since the VTR operates as an NTSC system, 50 was output from the output end 92, but based on the tape identification result Table 7, the output state of the state/discrimination circuit 156 is inverted. , 1 will be output from the output terminal 92, and each block shown in FIG.
Switch to R system.

It will be done. In addition, the input to the gate circuit 87.

The power signal may be an output signal of the waveform thickening circuit 49.

Next, FIG. 11 shows another component of the system identification circuit 44.

An example of body circuit is shown. In Figure 11, system jobs.

The separate circuit 44 holds level identification circuits 99 and 100.

It is composed of circuits 101 and 102 and R8-F, F, and 127.

ing. The level identification circuit 99.100 has two terminals.

VC of a clock recovery PLL circuit consisting of a doubler circuit 50, a phase comparator 51, a filter, and a Vcos 5°.

Control No. 1a of 055 inputs. The above clock regeneration PL
The frequency of the clock reproduced in the L circuit is 11°58 in the NT8C system and 11.5 in the CCIR system.
MH! Therefore, depending on whether the video tape recorder is operating in the NT8C system or the CCI system, the clock frequency/wave number will be as shown in Table 8. Therefore, VCO 550 control signals corresponding to the values in Table 8 are obtained, and the DC potential of each control signal is shown in Table 9, for example.

The value is as follows.

Table 8 Table 9 Here, set the discrimination level of the level discrimination circuit 99 to 2.25V.
, the discrimination level of the level discrimination circuit 100 is set to 2.75V, and when the input level is smaller than the discrimination level of the level discrimination circuit 99 or greater than the discrimination level of the level discrimination circuit 100, each level discrimination circuit 99, 10
Assume that 0 outputs 1. Video tape recorder operating system and BS-F.

The relationship with the output of F, 127 is shown in Table 10,
51" for CC engineering A system and NTSC system.

At the time, "'0" is output from the output terminal 105. 5
Table 10 Then, the video tape recorder is set to N'rSC.

It operates as a CCIR system.

When we play back a tape recorded in 105 outputs 1, and each block shown in FIG. 7 is switched to the CCIR system.

, 0 Note that the hold circuit 101
, 102 is a gate pulse signal (No. 1) output from the PCM processor 56.

2 Figures 01-G5) It works.

The above is the system identification method using PCM signals.

Although this has been described using three embodiments, it is clear that other configurations may be used. .

〔Effect of the invention〕

According to the invention, it is also explained in the above embodiments.

Just like the NTSC system and CCIR system.

A reliable recording system with a simple circuit configuration that allows even 1° recording on tapes recorded with either system.

This makes it possible to identify any type of tape and switch the corresponding playback system.

It becomes possible to playback and has the advantage of a video tape recorder.

The effects are significant, including the ability to greatly expand the range of uses.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the video tape recorder of the present invention, FIG. 2 is a signal waveform diagram of each part of FIG. 1, and FIG. 6 is a component of the ATF processing circuit. ．． 4 is a block diagram showing the PCM signal/signal processing circuit, FIG. 5 is a block diagram showing another embodiment of the system identification/identification port, and FIG. 6 is the system. FIG. 7 is a block diagram showing another embodiment of the video tape recorder 5 of the present invention;
FIG. 8 is a block diagram showing another embodiment of the system identification circuit. FIG. 9 is a development diagram of the recording signal, and FIGS. 10 and 11 are diagrams. 5 is a block diagram illustrating another embodiment of the system identification circuit. 12 and 16 show conventional video tape recorders. FIG. 6 is a recording pattern diagram of the -da signal. 40, 44... system identification circuit 8B, 95, 106, 117, 125, 128. '15
5,157,138. . 169...Tank circuit 89, 94, 107, 118, 124, 12
9, 140, 141, 142□5...Peak detection circuit 90, 95, 108, 119, 125, 15
0, 145, 144, 145°101, 102
...Hold circuit 127...R8-7 lip-flop 41, 156, 147...Status determination circuit
2゜36. 56...PCM processor 35...controller! cormorant

Claims (1)

[Claims] In a helical scan video tape recorder having means for forming a diagonal track on a magnetic tape and means for recording and reproducing the diagonal track divided into a plurality of pieces, A video tape recorder comprising: means for extracting a signal; means for generating an identification signal based on the extracted signal; and means for switching a reproduction circuit based on the identification signal.