JPS60109391A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To decrease the number of oscillators by using the oscillator which oscillates by integer multiples of the horizontal synchronizing frequency for tracking pilot signal generation and for time-sharing multiplex clock signal generation in common. CONSTITUTION:After chrominance signals R-Y, B-Y and a luminance signal Y from a video signal generator 30 are time-compessed by RAMs 41, 42, 43 and 44, they are time base multipled by a synthesizing circuit 45. The output of the synthesizing circuit 45 is taken out by a D/A converter 46 as a time division multiplex signal, and after the frequency is modulated by a frequency modulation circuit 50, the signal is written in a recording medium 19. At this time, the signal, which is phase-synchronized to a horizontal synchronizing signal from a voltage controlling oscillator VCO40 for clock signal generation which is used for time- base compression, is led to a pilot signal generator 29, and is used as the reference signal of a pilot signal for tracking.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a device for recording and reproducing a color video signal by time-division multiplexing a luminance signal and a color signal, and particularly relates to a device for recording and reproducing a color video signal by time-division multiplexing a luminance signal and a chrominance signal. -Relates to a pilot signal generation method that enables tracking with good compatibility with playback devices.

[Background of the invention]

A video tape recorder (hereinafter referred to as VTR) is one of the devices for recording and reproducing color video signals. Conventionally,
General home VTRs employ a color under recording method to record color video signals. An example of this color under recording method is the A5 video standard.

The 8-way video standard has a narrower video track pitch than the conventional home V'T IIL standard, and requires improved tracking accuracy of the video head.

For this reason, as a tracking technology in 8-Tou Video LI% M5, four low-frequency pilot signals with a frequency of P can be cut off for each video track, and the frequency multiplicity is recorded in the video signal, and when playing back, each video track A four-frequency pilot system is used to detect the tracking pilot signal from the tape and control tape running for optimal tracking.

FIG. 1 shows an example of a system block diagram that implements the CCI If method of the 8K video standard.

In FIG. 1, 1 is an input terminal for an audio signal, 2 is an audio processing circuit that applies emphasis to the audio signal, 3 is a frequency modulator that modulates the audio signal with a center frequency of about 1.5 MHz, and 4 5 is a band-pass filter (hereinafter referred to as BPF) that extracts the modulated audio signal, 5 is an input terminal for a color translation signal, and 6 is an automatic gain control circuit (hereinafter referred to as AGC) that optimizes the amplitude level. , 7 is a low-pass filter (hereinafter referred to as LPF) that does not extract only the luminance signal (hereinafter referred to as Y signal) from the color video signal, 8 is an emphasis circuit that emphasizes high-frequency components, and 9 is an amplitude limiter. clip circuit; 10 is a frequency modulator for frequency modulating the Y signal; 1;
1 is a high-pass filter (hereinafter referred to as HP F) that extracts the frequency-modulated Y signal; 12 is the BPF that extracts the color signal from the color video signal; 13 is the frequency-modulated audio signal and Y (No. 14 is a color killer circuit, 15 is an LPF that takes out the low-frequency converted color signal, 16 is an audio signal, a Y signal 2-band signal, and a tracking pilot signal. 19 is a video tape, 20 is a synchronization separation circuit for extracting a horizontal synchronization signal from the Y signal, 21 is a phase comparator, and 22 is a phase comparator. A voltage controlled oscillator (hereinafter referred to as V
23 is a divider that divides the frequency of the output of the VCO 22, and the phase comparator 21, the VCO 22, and the frequency divider 23 constitute a PLL, and the output of the VCO 22 is phase-synchronized with the horizontal synchronizing signal. A signal with a frequency of 375 fH is obtained. 24,25°26.27 is a frequency divider, and the frequency division ratio of each divider is 1158, 1150.1/36.1/40
, and the frequencies of the respective output signals f 1 to f 4 are
(f 1”6.5 fHHf ”’7.5 fH*f3
"10.5 fH, f4": 9.5 fH. 28
is the signal f1 to f4 for each video track from f1 to f
2→f3→f4, and the output of this switch circuit 28 is supplied to the write amplifier 16 as a tracking pilot signal.

The 8-video standard strictly specifies the frequency of the tracking pilot signal for the CCI 14 system as follows.

Therefore, the pilot signal generator 29 shown by the broken line requires a PLL circuit with a center frequency of 375 fH, thereby improving tracking accuracy and making it possible to have compatibility.

However, the color under recording method adopted in the B nm video standard has the disadvantage that it is difficult to secure a sufficient S/N ratio of color signals and a sufficient band of Y signals.

One of the means to solve this drawback is a time division multiplex recording method in which the Y signal and the color signal are multiplexed and recorded on the time axis.

FIG. 2 is a system block diagram of an example of implementing this time division multiplex recording, and FIG. 3 is a diagram illustrating a signal format used in the time division multiplex recording system. Below, Part 2. The time division multiplex recording method will be explained in FIG. 3 (G).

In FIG. 2, 30 is a video signal generator;
Y signal 3a, (RY) signal 3b, (B-Y) shown in the figure
Outputs signal 3C. 31ζ is a switch circuit, (
The (RY) 1 word 3b and the (B-Y) signal 3C are switched every horizontal period, and the output becomes a line-sequential color signal. 3
2.33ζ is an A/D converter that converts an analog signal into a digital signal, 34 is a horizontal synchronization separation circuit, 35 is a phase comparison circuit, 36 to 39 are frequency dividers, 40 is CO, and phase comparison circuit 35 P with frequency dividers 36 to 38 and VCO 40
The output of the CO40 is a signal NfH that is phase-synchronized with the horizontal synchronization signal, the output of the 1/4 frequency divider 39 is a clock signal C1 of NfH/4, and the output of the 115 frequency divider 38 is is Nfl (15 clock signal C2 power 5.1/
The output of the 4 frequency divider 37 is a clock signal C of NfH/20.
3 is obtained. 41 to 44 are time axis conversion I(, AM(
random memory), RAM141 and RAM242
For example, the digital signal from the 10th A/D converter 32 is alternately converted into a clock signal C of NfH/20 every horizontal period.
Similarly, Nfn/4 is written alternately every horizontal period.
From this, (IL-
y) Compress the line-sequential color signal time @ of the signal and the (B-Y) signal to 1. Also, RAM343 and 1 are also AM444
For example, the digital signals from the second A/D converter output are inputted alternately every horizontal period by a clock signal c of NfH/5.
2, and similarly write NfH/lζ alternately every horizontal period.
From this, the time axis of the Y signal is 415? ζ Compress. Reference numeral 45 denotes a synthesis circuit, which multiplexes the N sequential color signals and the Y signal, which have been time-compressed as described above, on the time axis. 46 is a D/A conversion gain for converting a digital signal into an analog signal.
A time division multiplexed signal 3d shown in the figure is derived. 47 is a clamp circuit for clamping the synchronous tip or pedestal; 4
8 is a dynamic emphasis circuit that emphasizes a small amplitude signal, 49 is a clip circuit, 5o is a frequency modulation circuit, and the other parts are the same as those in FIG. 1, and as described above, the Y signal and color signal are time-division multiplexed. The signal 3d is frequency modulated and recorded.

This time-division multiplexing recording method not only improves the color signal by 87N, but also suppresses the interference between the two signals that was caused by frequency multiplexing the Y signal and color signal in the conventional color under recording method, improving image quality and It is expected that the Y signal will have a wider band. Therefore, it is suitable for high-density recording.

However, in order to achieve high-density recording in a VTR or the like, improvement in tracking accuracy is required as described above. As a technique for solving this problem, there is a 4-frequency pilot system adopted in the above-mentioned 8-frequency video standard.

However, in this case, it is necessary to stabilize the frequency of the pilot signal in order to improve tracking, 1'-R&, and compatibility, and the pilot signal generator 29 uses P L L as in the example in FIG. Type VCO or X'ta
1 oscillator is required.

Therefore, the clock signals CI, C for time division multiplexed signal processing
2. PLL to generate C3 and PLL to generate tracking pilot signal or expensive X't
An a1 oscillator is required, increasing the circuit configuration. Also, I
Even when attempting to use C, the number of peripheral parts increases, making it difficult to reduce costs. [Objective of the Invention] An object of the present invention is to improve the recording/reproducing apparatus of the conventional color under recording method in the time division multiplex recording method. It is an object of the present invention to provide a magnetic recording and reproducing device which is compatible with tracking with the above, reduces the number of oscillators used for tracking pilot signals, and facilitates the implementation of a pilot signal generation circuit into an IC.

[Summary of the invention]

For the above purpose, in the present invention, the oscillator used for the tracking pilot signal and the VCO of the clock signal generation circuit used for time division multiplexed signal processing are used together.

Further, the center oscillation frequency of the VCO of the clock signal generation circuit is selected to be an integral multiple of 378 fH or 375 fH.

[Embodiments of the invention]

The magnetic recording and reproducing apparatus of the present invention will be explained below with reference to an embodiment shown in FIG.

The configuration of this embodiment is almost the same as the example shown in FIG. 2, but in FIG. In the embodiment shown in the figure, the VCO 22 is not provided, and a VC for generating a clock signal used for time axis compression or expansion is used.
A signal phase-synchronized with the horizontal synchronization signal from O4o is guided to the pilot signal generator 29, which serves as both vCOs.

In this embodiment, as described above, the Y signal of the CCIR system is time-base compressed into v5, and the line-sequential color signal is into IA, respectively, and time-division multiplex recording is performed.

In this case, the oscillation frequency N of the clock signal VCO 40 is
It is preferable to select fH to be an integral multiple of 150OfH. In one embodiment of FIG. 4, Nfn is selected to be 600OfH, and the respective clock signals Cs, C2, C3 are Ol-150OfH.
u C2-1200fH Cs ex 300 fH. In this case, the frequency of the signal guided to the tracking pilot signal generator 29 is, for example, 1500f.
By dividing this signal by 1h in the divider 51, a signal of 375 fH is obtained, and by dividing this signal by each of the dividers 24 to 27 (81 fH shown in equation 1)
It is possible to obtain a tracking pilot signal that satisfies the M video standard.0 Figure 5 shows a Y signal of 46,
This is another embodiment of the present invention in which a line-sequential color signal is time-base compressed and recorded in 115, and shows the configuration of a clock signal generation circuit and a tracking pilot signal generator 29.

In FIG. 5, 52 is an input terminal for a horizontal synchronizing signal or a signal synchronized thereto, 53 is an output terminal for a pilot signal, 54 is a 1/3 frequency divider, and the other parts are the same as in FIG. In this embodiment, the oscillation frequency N of the clock signal VCO 40 is
fHfxsoo fmco is selected to be 3 times 450OfH, and in this case, the respective clock signals CI, C2,
C3 is C101125fn C2ee 900 fH C3 agony 225 fH Kinaru. Further, the obtained tracking pilot signals f1 to f4 satisfy the 8 Dragon video standard as in FIG. 4.

FIG. 6 shows an embodiment of the present invention in which the Y signal is compressed to 4 in the NTSC format and the line sequential color signal is compressed to 115 in the time axis. The feature in this case is that the clock signal VCO
The oscillation frequency of 40 is selected to be an integral multiple of 378OfH.

Similarly to FIG. 5, FIG. 6 shows the configuration of the clock signal light 8E circuit and the tracking pilot signal generator 29 - ζ, where 55 is a 1/2 frequency divider, and the others are shown in FIGS. 4 and 5. is the same as In this embodiment, the clock signal VC
The oscillation frequency Nfm of O40 is selected to be 378OfH, and in this case, each clock signal CI, 02. C3
becomes 01 +w 945 fH C2e756fH Ca F-189fn. However, the NTSC standard specifies the frequency of the pilot signal for tracking in the NTSC system.
By selecting the oscillation frequency Nfn to be an integer multiple of 378OfH, pilot signals f1 to f4 that satisfy equation (2) are obtained.
can be obtained.

Figure 7 shows the case where the Y signal of the CCI R system and the NTSC system is compressed on the time axis to V5, and the line sequential color signal is compressed to 115. This is an example. The feature of this case is that the oscillation frequency NfH of the clock signal VC040 is
NTSC system and NTSC system.

In the embodiment shown in FIG. 7, the frequency division ratio of the frequency divider 36 is switched between 1/375 and 1/378 by a discrimination signal between the CCIR system and the NTSC system from the input terminal 56, and V C0
40O oscillation frequency 111. NfHe-7500fu door 560fH is switched. In this case, each clock signal Cx, C2, e3 is, for example, C in the ccxa system.
131875 fH C2 and 1500 fH C3 set 375 fH, and in the NTSC system, for example, C1 set 1890 fH C2'= 1512 fH Cs "e 378 fH. In this case, the tracking pilot signal f1
~ f4 is 8WI+11 for both CCIR and NTSC systems
Satisfies video standards.

Next, the present invention will be described in the case where a line-sequential color signal is time-axis compressed to 1/3 and recorded in the 'Y-fold signal 73. The time division multiplexing recording system block in this case is basically the same as that shown in Fig. 2 or Fig. 4, but the RA for time axis conversion is
The writing and reading clock signals C1 to C3 of M41 to M44 are different, and the frequency ratio of each clock signal is selected to be C1:C2:C3=3:2:1. 3e in FIG. 3 is an example of a time division multiplexed signal in this case.

FIG. 8 shows how to convert the Y signal to V3 using the CCII
This is an embodiment of the present invention in which a line-sequential color signal is compressed in the time axis to 1/3 and recorded.

The feature of this case is that the oscillation frequency NfH of the clock signal VCO 40 is selected to be an integral multiple of 75OfH.

In FIG. 8, reference numerals 57 to 59 are dividers, and the respective frequency division ratios are 1/2, 1/3, and 1/2, and the others are the same as in FIG. 5. In this embodiment, the oscillation frequency NfH of the clock signal VCO 40 is selected to be 2250 fH, which is three times that of 7501H, and in this case, each of the clock signals CI, C2, and C3 is CI = 1125 f.
HC2! 750 fH C3 gourd 375 flll. The frequencies of the tracking pilot signals f1 to f4 also satisfy the 8-channel video standard.

Similarly, the present invention 4 can be used to convert the Y signal to 2/2 in the NTSC system.
To 3? Although not shown, when recording the fM sequential color signal 7i-1/3 with time axis compression, the clock VCO 4
The oscillation frequency INfn of 0 is traced to the gloss number times 756fH.

Figure 9 shows the Y signal of CCIR system and NTSC system.
3, record the line-sequential color signal by compressing the time axis to 1/3,
This is an embodiment of the present invention that is compatible with the CCI R system and the NTSC system. In this case as well, as in FIG. 7, the clock V is
Oscillation frequency of CO40 NfH/! l-Switch.

In one embodiment of FIG. 9, the frequency divider 560 divides the ratio (qCI)
The oscillation frequency NfH of VCO40 was changed to 1/500 and IA04 between the L method and the NTSC method, and the oscillation frequency NfH was changed to 3000.
Switch as fH and 3024J'H. In this case, the respective clock signals CI, C2, and C3 become, for example, C1=1500 fH C2 1000 fH 03W 5QQ fH in the CCIR system, and become, for example, C1;1512fH C2-xoosfH C3=504 fH in the NTSC system. In this case, the tracking pilot signal ft
-f4 satisfies the 8-interval video standard as in the embodiment of FIG.

Next, the Y signal is set to V3, and the color signal component R-Y signal and B-
The present invention will be described in the case where a Y signal, a speech signal, and a Q signal are simultaneously time-compressed and recorded in each IA.

FIG. 1O shows an embodiment in which the present invention is used to compress and record data along the time and minute axes as described above.

In Fig. 10, the division ratios of 58 to 6o are 1/3, respectively.
, 1/2, and 1/4 frequency dividers, 61 to 63 are A/D converters, 64 to 69 are time axis conversion RAMs, 70 is a frequency divider, and the others are the same as in FIG. In this example, R-
The Y signal and the B-Y signal are simultaneously converted into digital signals by A/D converters 61 and 62, and similarly to the second embodiment, they are written to and read from the respective RAMs 64 to 66, and the R-
The Y signal and the B-Y signal are time-base compressed into IA, and the Y signal converted into a digital signal by the A/D converter 63 is similarly converted into IA.
(Writes to AM67.68, reads it, compresses the time axis to V3, and separates the time axis compressed R-Y signal and B
- Time-division multiplexing and recording of the Y signal and the Y signal. 3f in FIG. 3 is an example of a signal time-division multiplexed in this manner, in which the B-Y signal, the B-Y signal, and the Y signal are sequentially time-axis multiplexed. In this case, time axis conversion RAM64-6
9 write and read tally clock signals C1°C2,
The frequency ratio of 03 is C1:C2:C3■6:42l.

In the CCIR method, by selecting the oscillation frequency NfH of the clock VCO 40 to be an integral multiple of 150ofH,
The frequencies of the tarokk signals CI, C2, and C3 are all integral multiples of fH, and the output of the frequency divider 71 in the tracking pilot signal generator 29 can be set to 375fH, which is a tracking pilot that satisfies the 8xi video standard. I can get a signal. In this case, the branch unit 36,
The division ratio of 70 is a fraction of an integer, and the configuration is easy. For example, the oscillation frequency Nfn of the clock VCO 40 is set to 15
If 450OfH, which is three times 0OfH, is selected, each clock signal CI, C2, CBG-I C1 = 2250 fH C2" 1500 fH Cs = 375 fH. Also, the frequency divider 700 frequency division ratio is set to 1/12. By selecting this, a signal of 375 fH can be obtained at the output.

In the NTSC system, by selecting the oscillation frequency NfH of the clock VCO 40 to be an integral multiple of 756fH,
Similar to the CCIR method, the frequencies of the clock signals CI, C2, and C3 are all integral multiples of fu, and it is possible to obtain a tracking pilot signal that satisfies the 8-frame video standard. For example, the oscillation frequency N of the clock VCO 40
If fH is selected to be 4536fH, which is six times 756fH, the respective clock signals CI, C2, and C3 become C1-2266fH C2-=ts12fu Ca g+=378 fH. Further, by selecting the division ratio of the frequency divider 700 to 1/12, a signal of 378 fH can be obtained at the output.

Also, in this case, similarly to the embodiments shown in FIGS. 7 and 9,
For example, the oscillation frequency Nfu of the VCO 40 is changed to CC by switching the division ratio of the frequency divider 36 between the CCIR method and the NTSC method.
4500fH when using IR method, 453 when using NTSC method
By setting it to 6fH, both types can be used in common.

In FIG. 11, the Y signal is compressed on the time axis in the stirrup using the CCIR method, and the color signal is compressed on the time axis to 1/3 line-by-line in the same way as the example in FIG. 6 or the embodiment in FIG. , time-division multiplexing, and time-division multiplexing of the color signal by simultaneously compressing the R, -Y signals and B-Y signals into IA as in the -H embodiment in Figure 1O. This is a one-bag embodiment of the present invention that uses a dual-purpose method.

In FIG. 11, 71 is an input terminal for a control signal that selects whether to compress the time axis of the color signal to 1/3 line-sequentially or simultaneously to 1/6; and 72 is a branch station in the above case. In the case described later, the clock signal from the frequency divider 74 is
This is a switch circuit that guides the clock signal from C.3 as the clock signal C3, and the rest is the same as that in FIG. In this embodiment, the clock VCO 400 oscillation frequency NfH
is selected to be 300OfH, which is twice 1500fIz,
In this case, the respective clock signals CI, C2, and C3 become C1=1500 fH C2-1000fH C3e+500fH in the above case, and become C1e=1500 fH C2=1000 fH 03m 250 fH in the case described later. The tracking pilot signal obtained satisfies the 8-video standard.

In the NTSC system, the oscillation frequency NfH of the VCO 40 is set to 7
By selecting an integer multiple of 56fH, a time division multiplexing method similar to that shown in FIG. 11 becomes possible. For example (Ma NfH 302
If 4f+t is selected, each clock signal CI.

C2 and CB are in the above case C1=1512 fH C2=　1008　jH 03 Tomi 504 fH In the case described below, CI” 1512 fH C2=1008 fH Ca = 252 fH becomes.

FIG. 12 shows a method for switching the time axis compression ratio of color signals as in the embodiment shown in FIG.
This is an embodiment of the present invention that is compatible with the C method.

The circuit operation of this embodiment is similar to that of the embodiment shown in FIG.
This is a combination of the operations of the embodiment shown in the figure, and can be easily inferred.

In the above embodiments of the present invention, an example of the oscillation frequency Nfsr of the clock VCO has been described, but the present invention is not limited to the frequencies raised in the above embodiments.

By using the present invention, a device that time-division multiplex records and reproduces Y signals and color signals can be tracked compatible with f3 m video, which is a conventional color angle recording and playback device. Even when it becomes possible to use a tracking pilot signal, it is possible to reduce the number of oscillators for generating a tracking pilot signal.

This simplifies the circuit configuration, making it possible to significantly reduce costs, especially when integrated into an IC.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional 8-video CCIR system, and Fig. M2 is a block diagram showing a conventional 8-video CCIR system.
FIG. 3 is a block diagram of a system that satisfies the tracking pilot signal conditions of Homo Video. FIG. 3 is a diagram showing an example of the signal format of the time division multiplex recording method. FIG. FIG. 5 is a block diagram showing another embodiment of FIG. 4, and FIG. 6 is a block diagram showing an embodiment of the present invention applied to N.
FIG. 7 is a block diagram showing an embodiment in which the present invention is applied to the C'CIR method and the NTSC method, and FIG. FIG. 9 is a block diagram showing another embodiment of the CCI It seven directions of the invention, and FIG. 11 is a block diagram showing another embodiment using the CCIR method of the present invention. FIG. 12 is a block diagram showing another embodiment using the CCIR method of the present invention.
FIG. 7 is a block diagram showing another embodiment in which the IR method and the N, TSC method are used together. Explanation of symbols 29...Tracking pilot signal generator 35.
...Phase comparator circuits 36-39...Broadcaster 40...VCO for clock signals 32, 33...A/"D converters 41-44...几AM 46...D/A conversion Input terminal 53 for a horizontal synchronizing signal or a signal synchronized therewith; Output terminal 56 for a tracking pilot signal; Input terminals 57 to 60 for CCIR/N'l'SC switching control signal; Branchers 61-63...A/D converters 64-69...RAM 71...Input terminal 72 for multiplexing system switching control signal...
Switch circuit diagram 6 Figure 6

Claims (1)

[Claims] In a device that time-division multiplexes at least a luminance signal and a chrominance signal, converts it into a frequency modulated wave, and records the frequency-multiplexed wave on a recording medium together with a tracking pilot signal, a clock for time-base compression of the luminance signal and chrominance signal, respectively. A magnetic recording and reproducing device characterized in that the signal generation circuit is equipped with an oscillator that oscillates at an integral multiple of the horizontal synchronization frequency fH, and the output signal of the oscillator is guided to a tracking pilot signal generation circuit to be used as a reference signal for the pilot signal. .