JPS63149983A - Color video signal recorder - Google Patents

Abstract

PURPOSE:To record luminance and chrominance information in an excellent way over a wide band by forming the broad band luminance information as 1st and 2nd signals with the same form and having equal frequency as to the handled information and applying frequency division to the chrominance information only for the low frequency region as multichannel processing. CONSTITUTION:The luminance signal is FM-modulated as 8.4MHz for SYNC tip and 10.84MHz for white peak level, a 1st signal inverted synchronously with the leading of the FM modulation wave and a 2nd signal inverted synchronously with the trailing are formed and they are used for the two channel of luminance signal of 1st and 2nd channels. A chrominance signal subjected to low frequency conversion is superimposed in one of the two channels and a color difference signal including the high frequency color information not included in the chroma signal is arranged at the low frequency of the other channel to apply frequency multiplex. Thus, the signal of the 1st channel is recorded by heads 1A, 1B and the signal of the 2nd channel by heads 2A, 2B are recorded and reproduced to/from a magnetic tape 4 in an excellent way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video signal recording device, and more particularly to a video signal recording device No. 1'ε for recording a wideband video signal.

[Prior Art] In recent years, various high-resolution, wideband television signal standards have been proposed in order to improve the reproduction quality of television signals. For example, the so-called higi-def, where the number of scanning lines is 1125 and the luminance signal band is about 20 MHz.
tion television (HD-TV) signal, a so-called extended-def signal that is compatible with current television signals and has a luminance signal band of approximately 8 MHz.
Initiation television (ED-TV) signals and the like have not been proposed.

When considering recording and reproducing these wideband television signals, current video tape recorders have a recordable and reproducible band of about 4 MHz, and cannot record and reproduce the above-mentioned wideband television signals. Therefore, various proposals have been made for VTRs that convert conventional wideband television signals into multi-channels, suppress the band to about 4 MHz for each channel, and perform recording and playback.

(Problem to be solved by the invention) However, when assuming a VTR that performs multi-channel recording as described above, even if a composite video signal is made into multi-track by a simple method such as band division, the effects of jitter etc. It must be removed with great precision,
The circuit configuration of the playback system becomes large-scale. In particular, when dividing a video signal into high-frequency components and low-frequency components, the time constants of the circuits that handle both components are different, so it is necessary to time-align these image frequency components during playback to restore the original video signal. It was extremely difficult to restore it.

Furthermore, when considering separating a composite video signal into component signals such as R, G, and B components for recording, each component signal is a wideband signal, so each of these must be converted into a multichannel signal. However, the number of channels increases dramatically, making it impossible to perform high-density recording.

Furthermore, in a VTR, it is desirable to record an audio signal, preferably a stereo audio signal, at a high relative speed, but it has been difficult to record such an audio signal using the methods described above. .

In recent years, various methods have been proposed for digitizing and recording video and audio signals, but since digitizing the signals further expands the band, high-density recording cannot be expected.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a video signal capable of recording a wideband video signal with high sound intensity for both luminance information and color information with a simple configuration.

[Means for solving problems]

For this purpose, in the video signal of the present invention,
A first signal that is inverted in synchronization with a rising edge of an FM modulated wave obtained by FM modulating a luminance signal in a video signal, and a second signal that is inverted in synchronized with a rising edge of the FM modulated wave are formed; a first multiplexed signal obtained by frequency-converting and multiplexing a progressive color signal obtained from low frequency components of two types of color difference signals in the signal to a low frequency range of one of the first signal and the second signal;
The high frequency component of at least one of the color difference signals of the species is
This signal and a second multiplexed signal that is multiplexed by placing it in the lower frequency range of the other second signal are recorded on a recording medium.

(Function) By configuring as described above, wideband luminance information can be generated in an extremely simple configuration, and the first and second signals have the same format and have the same frequency of information to be handled, and only color information can be processed by frequency division. Since only the low frequency band is multi-channeled, the influence of time axis fluctuations on the reproduced screen can be reduced, and wideband luminance information and color information can be recorded satisfactorily.

[Actual Bag Example] Hereinafter, one embodiment of the present invention will be described in detail. In addition, in the following, the video signal handled is a luminance signal band of 8 MH.
Assume an NTSC signal of about z.

FIG. 1 is a block diagram showing the configuration of a recording system of a VTR according to an embodiment of the present invention, and FIG. 2 (A).

(B) is a diagram showing the head arrangement in the VTR of FIG. 1;

In the VTR of this embodiment, the modulation frequency of the luminance signal is about twice that of the conventional one (for example, the sync chip part is
．． 4MHz, white peak part is 10.8MHz), and forms a signal that inverts in synchronization with the rising edge of this FM modulated wave and a signal that inverts in synchronization with the falling edge of the FM modulated wave,
These are assumed to be two channel luminance signals.

One of these two channels is superimposed with a low frequency converted chroma signal, and the other channel is superimposed with a low frequency color difference signal containing color information in a high frequency range that is not included in the chroma signal. It is used for multiplexing.

In FIG. 2, IA and IB are heads for recording the first channel recording signal, and 2A and 2B are heads for recording the second channel recording signal. Head IA
, IB rotate at 30 revolutions per second with a phase difference of 180 degrees, and the heads 2A rotate with phase differences close to these.

2B rotate with a phase difference of 180° from each other. Also, the azimuth angle of each head IA, IB, 2A, 2B is +
10@, -10@, +30°.

-30°. As shown in FIG. 2(A), a magnetic tape 4 is wound over an angular range of 180° or more around a rotary cylinder 3 to which these four heads are fixedly mounted, and the cylinder 3 is not shown by an arrow 5. Rotate in both directions. Further, the heads IA and 2A and the heads IB and 2B are fixedly installed on the cylinder 3 so as to have a predetermined step Tw as shown in FIG. 2(B).
This Tw will almost match the track pitch.

FIG. 3 is a diagram showing a recording pattern on a magnetic tape when recording is performed using the head shown in FIG. 2. As shown in the figure, two tracks are formed at the same time,
Tracks T, A, and T on which the first channel signal is recorded
, B and the track T2 where signals of the second channel are recorded.
AI72B will be arranged alternately. Also, the azimuth angle must be 20° on adjacent tracks as shown in the diagram.
This difference serves to prevent crosstalk from adjacent tracks during playback. Moreover, each head of the magnetic tape 4 has an 18° angle from a capstan (not shown) or the like.
It is made to run a distance corresponding to 2Tw while rotating (1/60 seconds).

Hereinafter, the recording signals supplied to each head will be explained in detail based on FIG. 1.

In FIG. 1, a terminal 10 is a terminal to which a luminance signal having a band of about 8 MHz and a composite synchronization signal from a wideband color video camera are manually input, and a terminal 41 has a band of 0 to 1.5 MHz (R-Y ) The terminal where the signal is input, 42 is 0
This is a terminal to which a (B-Y) signal having a band of ~0.5 MHz is input manually.

44 sets the input (RY) signal band to 0.5MHz
With a low pass filter (LPF) regulated below, this L
The (RY) signal output from the PF 44 and the (B-Y) signal input to the terminal 42 are supplied to the encoder 45.

The encoder 45 performs well-known quadrature two-phase modulation using the oscillation output of an oscillator 46 that oscillates at the color subcarrier frequency (f se ) to obtain a carrier color signal (chroma signal). This chroma signal is band-limited by a band pass filter (BPF) 47, and then mixed with the aforementioned luminance signal inputted to the terminal 10 by an adder 48 to form an NTSC composite television signal, which is used as a monitor for the camera. It is output from the terminal 43 as an output.

The composite television signal thus obtained is separated into a luminance signal Y and a carrier color signal (chroma signal) C by a comb filter 11.

The brightness signal Y has its high frequency components cut by a low pass filter (LPF) 12, and is then passed through a clamp circuit.

The signal is supplied to a luminance signal processing circuit 13 including well-known circuits such as a clip circuit and a pre-emphasis circuit.

The luminance signal processed by the circuit 13 is supplied to the FM modulator 14, where it is FM-modulated at twice the modulation frequency of the conventional signal (for example, 8.4 MHz for the sync tip portion and 10.8 MHz for the white peak portion).

This FM-modulated luminance signal is shaped into a pulse shape by a pulse shaping circuit 15, and is supplied to 1/2 frequency dividers 16a and 16b, respectively. The 1/2 frequency divider 16a performs 1/2 frequency division by inverting the high level (Hi) and low level (Lo) at the rising edge of the pulse output from the pulse shaping circuit 15. 16b, the falling edge is Hl
and LO is inverted to perform 1/2 frequency division.

That is, the 1/2 frequency divider 16a stores the timing of the rising edge of the pulse related to the FM modulated wave, and the 1/2 frequency divider 1
Similarly, in 6b, the timing of the falling edge is preserved. This situation is shown in Figure 4 (a), (b)-(c).
, shown in (d).

In the figure, (a) is the output of the FM modulator 14, (b>>: the output of the pulse shaping circuit 15, (C) is the output 2 of the 1/2 frequency divider 16a, and (d) is the output of the 1/2 frequency divider 16b. The output of each is shown.

The signals frequency-divided as described above (luminance signals of the first channel and the second channel) are each passed through a bypass filter (HPF
) 17a and 17b, and a low frequency converted chroma signal and a low frequency converted color difference signal, which will be described later.

Band components for the FM modulated audio signal are attenuated and supplied to adders 18a and 18b.

On the other hand, the chroma signal separated by the comb filter 11 is band-limited by a bandpass filter (BPF) 19, level-adjusted by a well-known ACC circuit 20, and then supplied to a balanced modulator (BM) 21 that performs frequency conversion. be done. In 8M21, the carrier frequency of Kuromai No. 8 is changed to a low frequency (for example, 7
43KHz).

As is well known, this idler signal is shifted by 11/2 fH based on the HD separated by the horizontal synchronizing signal (HD) separation circuit 23 in order to remove the crosstalk component of the signal. LP
F24 is for passing only the lower sideband component, which is a low-frequency converted signal, in the output of 8M21, and supplies it to the adder 18a as a low-frequency converted chroma signal.

The (RY) signal input to the terminal 41 is supplied to the BPFll, and the 0.5 to 1.5 MHz components are separated. This separated high frequency (R-Y) signal is passed through an amplitude modulator (AM).
) 112, the signal is AM-modulated by the oscillation signal of the oscillator 46, and this oscillation signal is added as a reference signal during the color burst period and then supplied to the BM 114. In 8M114, the idler signal generated by the idler signal generator 116 converts the carrier frequency to a low frequency 11/2 f H
The frequency is shifted. The amplitude-modulated color difference signal thus converted to a low frequency band is supplied to the adder 18b via the LPF 115.

Further, the L channel audio signal input from the input terminal 25 and the R channel audio signal input from the terminal 26 are supplied to an adder 27 and a subtracter 28, respectively. The adder 27 outputs the sum signal of both channels (L+
R), and the subtracter 28 outputs the difference signal of both channels (L-R
) are obtained, and after being subjected to processing such as emphasis and logarithmic compression in signal processing circuits 29 and 30, they are supplied to FM modulators 31 and 32. And this FM modulator 31.
The FM modulated audio signal outputted from 32 is added to the first channel and second channel signals by adders 33a and 33b.

The pilot signal generation circuit 34 is a circuit that generates a pilot signal for tracking control using a well-known four-frequency power formula, and generates four types of pilot signals by dividing the oscillation signal of the oscillator 35 by four different frequency division ratios. +a
Next output.

This frequency division ratio is sequentially switched at a timing based on a 30 Hz rectangular wave signal (PG) related to the rotational phase of the head. Note that this PG is output by the PG generator 36. The pilot signals obtained in this way are sent to adders 38a and 38b.
and is added to the signals of the first channel and the second channel.

The first
．． The frequency allocation of the recording signal of the second channel is shown in FIGS. 5(A) and 5(B) 1. :show. Since this allocation for both channels is exactly the same as that of a conventional VTR, it goes without saying that these are recordable signals.

In the figure, Y indicates a luminance signal, C indicates a chroma signal, CX indicates a high-frequency color difference signal, A indicates an audio signal, and P indicates a pilot signal component.

These first. The recording signal of the second channel is transmitted to the head I via recording amplifiers 39a, 39b, 3c, and 39d, respectively.
The signals of the first channel are recorded on the magnetic tape 4 by the heads IA and IB, and the signals of the second channel are recorded by the heads 2A and 2B, respectively, as shown in FIG. Therefore, four types of pilot signals are sequentially recorded on two tracks, one fffi type at a time.

FIG. 6 is a diagram showing the configuration of the reproduction system of the VTR of this embodiment. During playback, each head IA.

IB, 2A, and 2B are tracks T I A + T I [
1°Trace T2A and T2B.

The first channel signals reproduced by heads IA and IB are amplified by head amplifiers 51a and 51b, and each head traces each track by a switch 52a controlled by the PG generated by the PG generator 36 mentioned above. The signal inside is extracted as a continuous signal. The output of this switch 52a is supplied to the HPF 53a, and only the luminance signal of the first channel included in the reproduced signal is divided. A dropout compensation circuit (DOC) 54a is a circuit that replaces a dropout with a signal from one horizontal scanning period ago when a dropout occurs in the reproduced signal, and the luminance signal of the first channel via the circuit 54a is sent to a limiter. At 55a, level fluctuations are removed and a pulse is formed.

On the other hand, the signals of the second channel reproduced by the heads 2A and 2B are transmitted to the head amplifiers 51c and 51c, similarly to the first channel.
1d and converted into a continuous signal by switch 52b.

Similarly, a pulsed second channel luminance signal is obtained via the HPF 53b, DOC 54b, and limiter 55b.

The timing correction circuit 56 corrects the output timing of the luminance signal of the second channel in order to compensate for relative positional deviation between the heads during recording and reproduction.

The first result obtained in this way. The pulsed luminance signal of the second channel is supplied to a synthesis circuit 57 to obtain a pulsed FM modulated luminance signal related to the original broadband luminance signal. This synthesis circuit 5
7 is constituted by, for example, an exclusive OR circuit (EXOR), etc., and obtains an output as shown in FIG. 4(e).

The FM modulated luminance signal synthesized by the circuit 57 is demodulated by the FM demodulator 58, and returned to a light luminance signal by the signal processing circuit S9 including a de-emphasis circuit and the like. 60 is the frequency component (1/2f,
Frequency components near odd multiples of ) are removed. The noise component is suppressed by a noise reduction circuit (tlR) 61 and then outputted from a terminal 100.

The chroma signal separated from the output signal of the switch 52a by the BPF 63a has its reproduction level corrected by the ACC circuit 64a, and is then supplied to the 8M65a, where it is returned to the original band based on the idler signal generated by the idler signal generator 66a. It will be done.

The output of the 8M65a is supplied to a BPF 66a to remove unnecessary frequency components, and then supplied to a comb filter 68a. This comb filter 68a is the comb filter 60
It has the opposite characteristic (passing components near odd multiples of 1/2 fH), and is used to eliminate leakage of luminance signal components and audio signal components as well as crosstalk components of chroma signals of momentary contact tracks. It is.

That is, the component ('
(near an integral multiple of t'H), this is removed by the comb filter 68a and then supplied to the decoder 91.

Further, the idler signal generation circuit 66a is connected to the HD separation circuit 69.
An idler signal containing jitter generated in the recording/reproducing system is generated based on the reproduction HD separated by a and the color burst signal in the chroma signal output from the comb filter 68a, and the chroma signal output from the 8M65a. is the one with this jitter removed.

On the other hand, the high frequency (R-Y) signal separated from the output signal of the switch 52b by the BPF 63b is gain-controlled by the ACC circuit 64b based on the above-mentioned reference signal, and then supplied to the BM 65b to maintain the original transmission frequency fSC. It is considered to be an amplitude modulated signal.

The process of correcting time axis fluctuations and removing crosstalk between adjacent tracks in the 8M65b is similar to that of the chroma signal in the 8M65a, with the only difference being whether a color burst signal or the aforementioned reference signal is used. be.

This amplitude modulated (R-Y) signal is transmitted to the timing correction circuit 7.
After the timing is matched with the chroma signal described above at 0, the signal is demodulated by the AMM modulation circuit 89.

The decoder 91 has a band of 0 to 0.5 MHz (
The (RY) signal and (B-Y) signal are output, respectively, and the (B-
Y) signal is output from terminal 92. The other decoder 91
The (R-Y) signal obtained from the AMM modulation circuit 89 demodulates the (R-Y) signal of 0, 5 to 1.5 MHz and the adder 9.
After being added at 0, the signal is output from the terminal 93 as a wideband (RY) signal.

Further, the FM modulated audio signal (sum signal) separated from the output of the switch 52a by the BPF 73a is sent to the FMM modulator 7.
After being FM modulated by 4a, the noise reduction circuit 75
At step a, noise removal, etc. according to the aforementioned emphasis and logarithmic compression is performed, and a reproduced sum signal (L+R) is obtained. Similarly, the FM modulated audio signal (difference signal) separated by the BPF 73b from the output of the switch 52b is transmitted to the FMM modulator 74b.
After being demodulated, a reproduced difference signal (LR) is obtained via the noise reduction circuit 75b. Further, the reproduced difference signal (L-R) is supplied to a timing correction circuit 76 to match the timing with the reproduced sum signal (L+R). These signals are then supplied to an adder 77 and a subtracter 78, from which L channel and R channel reproduced audio signals are obtained, respectively.

In this way, L channel and R channel reproduced audio signals are obtained from the output terminals 101 and 102.

The output signal of the switch 52a is sent to the head I in a delay circuit 79.
The signal is delayed by a period corresponding to the difference in trace timing between A and IB and the heads 2A and 2B, and is added to the output signal of the switch 53a by an adder 80. The output of adder 80 is LPF81
The pilot signal component is separated and supplied to a tracking control signal generation circuit (ATF circuit) 82. Along with this, the ATF circuit 82 performs the well-known processing associated with the four-frequency system using two adjacent tracks that are simultaneously traced as one unit, and obtains a tracking error signal. Based on this tracking error signal, the tracking control circuit 86 controls a capstan (not shown), etc., and controls the running of the magnetic tape 4 so that each head accurately traces the target track.

According to the above-mentioned VTR, it is possible to easily configure a video signal containing wide-band erotic flu and luminance information, minimize deterioration due to time axis fluctuations, and record and reproduce it together with a stereo audio signal. . Also, by playing only one channel, you can check whether the narrowband
It is possible to play No. 3, or if you have the first channel, you can play monaural audio signals. In other words, even with a VTR that reproduces only the recorded signal of the first channel, such as a conventional two-head VTR, the VTR of this embodiment can be used.
It is possible to reproduce the recorded signals by the above, and it is possible to provide so-called compatibility.

In the above-mentioned embodiment, the (RY) signal, which has been low-band converted after AM modulation, is frequency-multiplexed on the low band of the luminance signal of the second channel, but the (RY) signal and the (B-Y ) It is also possible to frequency-multiplex signals obtained by time-division multiplexing signals.

Furthermore, the signal form for the deaf can also be an FM modulation signal instead of the AM modulation and same frequency conversion format.

Furthermore, the FM modulated audio signal and the video signal are frequency multiplexed, but the FM modulated audio signal is recorded in the deep layer of the magnetic recording medium, and the video signal is recorded in the surface layer, so that they are recorded on the same track. It is also possible to do so.

Furthermore, although the so-called four-frequency method was used for tracking control, other methods may be used, for example, tracking control may be performed by recording a control signal relating to the track pitch along the edge of the tape and reproducing this control signal. It is also possible.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a color video signal recording device that can satisfactorily record and reproduce broadband color information and luminance signals with a simple configuration.

[Brief explanation of the drawing]

1 is a diagram showing the configuration of a recording system of a VTR as an embodiment of the present invention; FIGS. 2(A) and 2(B) are diagrams showing the head arrangement in the VTR of FIG. 1; The figure shows the recording pattern on the magnetic tape by the VTR in Figure 1, Figure 4 shows how the luminance signal is divided into channels, and Figures 5 (A) and (B) show the recorded signal of each channel. FIG. 6, a diagram showing frequency allocation, is a diagram showing the configuration of a reproduction system of a VTR corresponding to the recording system of FIG. 1. IA, IB are rotating heads for the first channel, 2A, 2B
is the rotary head for the second channel, and 14 is the FM for the luminance signal.
Modulator, 15 is a pulse shaping circuit, 16a, 16b are 1/2 frequency dividers, 18a, 18b are adders, 21 is a balanced modulator, 27 is an adder, 28 is a subtracter, 31.32 is for audio signal FM modulator, 33a, 3
3b is an adder, 44 is a low-pass filter, 45 is an encoder, 112 is an AM modulator, and 114 is a balanced modulator. 3rd plan 4th plan

Claims (1)

[Claims] a first signal that is inverted in synchronization with the rise of an FM modulated wave obtained by FM modulating a luminance signal in a color video signal;
A second signal that is inverted in synchronization with the rise of the modulated wave is formed, and a carrier color signal obtained from low frequency components of two types of color difference signals in the video signal is combined with the first signal and the second signal. A first multiplexed signal frequency-converted and multiplexed into the low frequency range of one of the signals, and a high frequency component of at least one of the two types of color difference signals are transferred to the low frequency range of the other of the first signal and the second signal. A color video signal recording device for recording a second multiplexed signal on a recording medium.