JPS62157498A - Color video signal magnetic recording device and magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To improve the resolution, sharpness and resolving power of a color in a VTR reproducing image by converting a compound color video signal to a pseudo component signal, recording it to magnetic recording media and restoring a reproducing pseudo component signal from the magnetic recording media to an original compound color video signal. CONSTITUTION:A RAM 7 respectively generates the data of an (a) group - a (c) group with 1H as a pause and with the data at every sampling period 1/fSC, in which the phase of respective sampling data comes to be mutually the same phase, as one group. A D/A converter 8 D/A-converts the digital data from an incoming RAM 13, generates an analog video signal and outputs to a FM modulator 10. A PCM sound signal and a FM analog video signal are recorded in a magnetic tape. A RAM 27, as well as the RAM 7, takes out one piece of data from respective groups of the data in order, generates the digital data and reads to the D/A converter 28 in accordance with a reading control signal PR'. The D/A converter 28 restores the original compound color video signal and outputs to an output terminal 29.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a color video signal magnetic recording device and a magnetic recording/reproducing device, and particularly relates to a color video signal magnetic recording device and a magnetic recording/reproducing device.
11 Signal of special component state that does not have transmission wave @(
The present invention relates to a color video signal magnetic recording device and a magnetic recording and reproducing device that convert the pseudo component signal into a pseudo component signal and record it on a magnetic recording medium, and restore the reproduced pseudo component signal from the magnetic recording medium to the original composite color video signal.

Conventional technology In general, when handling composite color video signals with a VTR, the influence of time axis fluctuation2 frequency band and waveform distortion (spurious)
It is necessary to carefully consider these three points. Here, the "direct color process method" used in broadcast VTRs deals with these considerations without compromise, but on the other hand, it is difficult to process color images at a high tape head relative speed of, for example, 25 to 40 m/s. Since the signal is directly recorded and reproduced using frequency modulation (FM), it has the drawback of requiring a highly accurate mechanism, a large-scale circuit, and a large amount of tape.

On the other hand, "
In the ``color under one type'' method, the FM luminance signal is converted to a frequency of around 700 kHz, which is lower than the FM band of the metering signal, at a relatively low relative tape/head speed of, for example, several m/s. Since recording and reproduction are performed in a superimposed manner, the drawbacks of the above-mentioned broadcasting VTR have been improved.

Problems to be Solved by the Invention However, the above-mentioned "color under one-way system" in the VTR
When a composite color video signal is recorded and reproduced in a conventional color video signal magnetic recording device and magnetic recording/reproducing device such as the above, only 1/21W of the information strength of the composite color video signal is actually reproduced. There is a problem in that the reproduced image suffers from insufficient resolution, sharpness, color resolution, and lack of detail.

Therefore, the present invention converts a composite color video signal into a pseudo component signal and records it on a magnetic recording medium.
It is an object of the present invention to provide a color video signal magnetic recording device and a magnetic recording and reproducing device that solve the above problems by restoring the reproduced pseudo component signal from a magnetic recording medium to the original composite color video signal.

Means for Solving the Problems The color video signal magnetic recording apparatus according to the present invention is comprised of a pulse generating means, an A/D converter, a storage means, a D/A converter, and a recording means. Here, the pulse generating means generates and outputs a sampling pulse and an iI+ control signal having n times the color subcarrier frequency fsc of the composite color video signal (where n is a natural number). The A/D converter samples the composite color video signal using a sampling pulse and outputs sampling data. The storage means stores the sampling data at a sampling period of 1 in which the sampling data is in phase with the color subcarrier of the composite color video signal within one horizontal scanning period.
/ f s The sampling data for each sc is converted into n groups of data, and the n groups of sampling data are arranged in series for each group in units of one horizontal scanning period according to the control signal. and read it out. The D/A converter converts the output data of the storage means into an analog video signal and outputs the analog video signal. The recording means frequency-modulates the analog video signal output from the D/A converter and records it on the magnetic recording medium.

Further, the color video signal magnetic recording and reproducing apparatus according to the present invention includes the pulse generating means and the A/D converter.

A first pulse generating means and a first A/D converter having the same functions as the storage means and the D/A converter, respectively.

A recording system comprising a first storage means, a first D/A converter, and the recording means includes a reproducing means, a second pulse generating means,
Second A/D converter, second storage means and second D/A
The configuration includes an additional regeneration system consisting of a converter. Here, the reproducing means outputs a reproduced signal obtained by reproducing and demodulating the recorded signal on the magnetic recording medium. The second pulse generating means generates and outputs a second sampling pulse having n times the color subcarrier frequency fsc of the reproduced signal and a second control signal, respectively. The second A/D converter converts the reproduced signal into a second
The sampled data of the n groups are restored and output by sampling with the constant frequency pulses. The second storage means repeatedly extracts each sampling data one by one from each group of n groups of sampling data from the second A/D converter in response to the second control signal. The second D/A converter performs digital-to-analog conversion on the output data of the second storage means to restore and output the original composite color movie signal. The pulse generating means generates a sampling pulse and a control signal. are supplied to the A/D converter and storage means, respectively. on the other hand,
After the composite color video signal is converted into sampling data by an A/D converter, it is supplied to a storage means, where the data arrangement is converted and converted into the n groups of sampling data. The sampling data of this n group is D
After being converted into an analog video signal corresponding to the pseudo component signal by the /A converter, the signal is recorded on a magnetic recording medium by a recording means.

Thereafter, the analog video signal (reproduction signal) reproduced by the reproduction means is transmitted to the second pulse generation means and the second pulse generation means.
The A/D converter, the second storage means, and the second D/A converter perform signal processing that is the opposite of the signal processing during recording, and the result is the original composite color video signal. will be restored.

Next, an embodiment of the apparatus of the present invention will be described with reference to FIGS. 1 to 5.

Embodiment FIGS. 1 and 2 are block system diagrams of an embodiment of a recording system and a reproducing system of a color video signal magnetic recording apparatus and a magnetic recording/reproducing apparatus according to the present invention, respectively.

First, the operation of the recording system of the apparatus of the present invention will be explained with reference to FIG. 1 and FIGS. 3(A) to 3(E).

In FIG. 1, a composite color video signal as shown in FIG.
The signal is supplied to an A/D converter 33 and a timing pulse generating circuit 4 via a GC circuit (GC circuit) 2, respectively. By the way, as is well known, the above composite color video signal has a color subcarrier frequency fs
c (For example, fsc=3.58 in the case of NTSC system
fs c = 4.43 for MHz and PAL systems
This is a signal obtained by band-sharing multiplexing a carrier color signal obtained by orthogonally modulating a color subcarrier (MHz) with two types of color difference signals into a luminance signal.

The timing pulse generation circuit 4 separates a horizontal synchronization signal from the incoming composite color video signal, and generates a timing pulse P with a period of one horizontal scanning period (one day) obtained by waveform shaping the horizontal synchronization signal. , a phase locked loop (PLL) 5 and a control device 6, respectively. PLL5
is based on the incoming timing pulse P, for example, the frequency 3 fsc (in the case of NTSC system, 3 f S
A pulse signal P1 having a frequency of 10.7 MHz) and a three-phase pulse signal P2 having a frequency fsc whose phases are shifted by, for example, 120 degrees from each other are generated and supplied to the υ control device 6, respectively.

The control device 6 operates at a frequency of 3fs based on the pulse signal P+.
c sampling pulse Ps,! Loading control signal Pw
, a read control signal PR and a pulse signal P3, respectively, and the A/D converter 3. Random access memory (
RAM) 7 and D/A converter 8, and
Based on the pulse signals P1 and Pz, an address signal PA is generated and supplied to the RAM 7.

A/D conversion@3 converts the incoming composite color video signal into the above sampling pulse Ps with a sampling frequency of 3 fsc.
For example, digital data with 7 or 8 quantization pits per sampling point is generated. Here, FIG. 3(B) shows a relationship diagram between the color printing carrier wave and each sampling point, and each 0 mark on the color subcarrier wave indicates each sampling point. In FIG. 3(8), since the sampling frequency is three times the color subcarrier frequency fsc, three types of sampling points having mutually different phases appear during one cycle of the color subcarrier. Each sampling data at these three types of sampling points is aI * bl , CI (or a2 * bz , 02
etc.), the A/D converter 3 generates digital data (a + bl
CIa2 bz c2...) and stores it in RAM7.
Output to.

The RAM 7 has a storage capacity for at least two days, and is used to rearrange and output incoming digital data, and sorts the incoming digital data in a predetermined manner according to the address signal PA and write control signal Pw. After that, data is written every sampling period 1/fsc, with one day as a break, and the phases of each sampling data with respect to the color subcarrier of the composite color video signal are in the same phase (referred to as "same phase data"). comrades as one group, data of group a (a+ 82...), data of group b (bl bz...), and data of group 0 (C+02...)
・) respectively. Next, the RAM 7 stores the above groups a to C.
The data of the groups are arranged in series in the order of group a, group b, and group 0, as shown in FIG. 3(C), and read out to the 0/A converter 8 in accordance with the read v control signal PR.

The D/A converter 8 performs digital-to-analog conversion (D/A conversion) on the incoming digital data from the RAM 13, and converts the time axis to 1/3 within one day, as shown in FIG. 3(D).
compressed into a, b.

An analog video signal in which three C color video signals are arranged is generated and outputted to an FM converter WJ unit 10 via an emphasis circuit 9.

FM modulation: The device 10 converts the incoming analog video signal into a frequency modulation (FM) obtained by frequency modulation of 1 ft (FM) t.
The analog video signal is output to the recording amplifier 11. The recording amplifier 11 receives a pulse code change 1 (PC
M) audio signal (PCM audio signal) and the above FM analog video signal are transferred to a rotating head drum (not shown).
Rotating heads H1 and H2 mounted opposite each other at 80°
supply to.

As a result, the PCM audio signal and FM analog video signal are recorded on a magnetic tape (not shown) (see Fig. 3).
E)).

Here, taking the NTSC system as an example, the band required to transmit the analog video signal is 5.4MH2 (43MHz).
fsc/2> or more, and the analog video signal is converted to VT.
When recording and reproducing in R, the VTR must be able to sufficiently pass this band.

In this case, taking the NTSC system as an example, the video system is 6M
Since a band of about Hz-343 is used, securing this in the FM system means that VTRs can use, for example, 8M1-IZ to 9MH7.
It becomes necessary to pass through a certain FM carrier. To address this, it is necessary to increase the tape head relative speed and thus, for example, double the rotational speed of the rotating head drum. As a result, the tape format by the device of the present invention is 1
This is so-called segment recording in which the composite color video signal of the field is composed of two tracks.

FIG. 4 shows an example of a tape format according to the apparatus of the present invention. Here, ■ to ■ indicate the center lines of each recording track, and the distance 11 [i (track pitch)] between the center lines of each track is set to, for example, 19 μm. In FIG. 4, the track shown in ■ is, for example, OH-131, 25
131.25)-1~2G for the track shown in H,■
2.5H, the track shown in ■ is 262.5) 1 to 39
3.75 H, 393.75 for the track shown in ■)
The above-mentioned FM analog video signals of -1 to 525H are recorded, and one frame of composite color video signal is recorded on the four tracks shown in (1) to (2).

Therefore, in the device of the present invention, intra-screen switching is performed. This intra-screen switching is difficult to process at seams, so it is better to avoid it, especially when dealing with composite color video signals, but the recording signal of the device of the present invention is
As mentioned above, since it is converted into a component state, it is only necessary to correct the seam to the extent that the skew is not visible. Therefore, with the device of the present invention, the burden on the time collector is reduced compared to the conventional method. reduced.

By the way, when the number of rotations of the rotary head drum is doubled as described above, the condition of 14 alignment between adjacent tracks may be such that the number of skips per track is an odd number multiple of 0.75H, for example. Even if the number of H jumps is 0.758, the tape running speed will be twice that of the standard mode, making it impossible to extend the length of the tape.Therefore, in the example shown in Figure 4, the number of H jumps is set to 0.758. Assuming 0.25 days, adjacent tracks will not be lined up in 1'', but every other track will have H.
I try to make it line up.

As a result, in the case of an azimuth head, high-speed search is possible, and during still playback, the rotating head H1
For example, H2 and H2 pass through the locus shown in ■, and a field still is established using the two tracks shown in ■ and ■. At this time, no discontinuity of H occurs, and a good still reproduction image is obtained. It turned out that it was possible to obtain

Note that crosstalk interference from adjacent tracks is reduced using the FM Zane-Lieve effect, but at this time, there is a difference in how the effects of crosstalk appear when the tracks are arranged in H and when they are not arranged in H. In the case where the number of H jumps is 0.25 H as described above, the synchronization signal portion of the adjacent track appears faintly like a ghost in the center of the screen. If this drawback is noticeable, it is sufficient to add a delay of, for example, 0.5H to the signal for every other track (this is not a problem in the signal processing by the digital circuit of the device of the present invention. FM modulation in which the carrier is set to a higher level may be used to make the ghost as described above less noticeable.

Next, the operation of the reproduction system of the apparatus of the present invention will be explained with reference to FIGS. 2 and 5(A) to 5(E). Here, the F reproduced from the magnetic tape by the rotating head 1 (1 and H2)
The M reproduction signal is supplied to a switch circuit 15 via preamplifiers 13 and 14, respectively. The switch circuit 15 switches and alternately outputs the respective output signals of the preamplifiers 13 and 14 in response to a switching signal from an input terminal 16 corresponding to the magnetic tape sliding scan period 11 of each of the rotary heads H1 and H2. . As a result, a continuous FM reproduction signal can be obtained. The output FM reproduction signal of this switch circuit 15 is supplied to the FM demodulator 18 and dropout detector 19 via the equalizer circuit 17, and the PCM audio signal in the output FM reproduction signal is supplied via the output terminal 20 to the FM demodulator 18 and dropout detector 19. It is output to the audio signal processing section that is not processed.

As shown in FIG. 5(A), the FM demodulator 18 performs FM demodulation of the incoming output FM playback signal and outputs the reproduced signal as shown in FIG. 5(B) to the A/D converter 21 and timing. The signals are output to the pulse generation circuit 22, respectively. The timing pulse generation circuit 22 separates a horizontal synchronization signal from the incoming reproduction signal q, generates a timing pulse P' obtained by waveform-shaping the horizontal synchronization signal, and supplies it to the PLL 23 and the control device 24, respectively. . The PLL 23 generates a pulse signal P+' with a frequency of 3 fsc and a three-phase pulse signal P2' with a frequency fsc based on the incoming timing pulse P', and supplies them to the control device 24. On the other hand, a clock circuit 26 having a crystal camera 25 generates a reference clock signal P4 with a frequency of 3 fsc and outputs it to the control YB device 24.

The control device 24 generates a sampling pulse Ps' and a write control signal Pw' based on the pulse signal P+' and supplies them to the A/D converter 21 and the RAM 27, respectively. , generates an address signal PA' and supplies it to the RAM 27. Further, the control device 24, based on the reference clock signal P4,
A read control signal @PR' and a pulse signal P3' are generated and supplied to the RAM 27 and the D/A converter 28, respectively.

However, since the output reproduction signal of the FM demodulator 18 includes a time axis error (jitter), the output pulse signals P+' and P2' of the PLL 23 also include jitter. Therefore, the sampling pulse Ps' write control signal Pw' and address signal PA' output from the control device 24 also contain jitter similar to the reproduction signal. Therefore, in the A/D converter 21 and RAM 27, which will be described later, signal processing is performed on signals that each include jitter, so that there is no influence of jitter accompanying this signal processing. Thereafter, the D/A converter 28 reads out the digital data from the RAM 27 using the read control signal PR' and the pulse signal P3' generated based on the jitter-free reference clock signal P4, and performs D/A conversion. As a result, an analog playback signal containing no jitter is obtained. In this way, compensation for jitter is provided.

The A/D converter 21 samples the reproduced signal as shown in FIG. 5(B) based on the sampling pulse Ps', and converts the reproduced signal into a data signal as shown in FIG. It is converted into digital data as shown in (C) and output to the RAM 27. In this digital data, each data group having the same phase per 1H is arranged in series in the order of group a, group b, and group 6.

Like the RAM 7, the RAM 27 has a storage capacity of at least 2H, and writes incoming digital data to a predetermined address according to the address signal @PA' and the read control signal Pw'. After that, data is extracted one by one from each group of data in order to generate digital data in which each data is arranged in the order (a+t)+C1a2b2C2...) as shown in FIG. The data is read out to the D/A converter 28 in accordance with the control signal PR'. D
The /A converter 28 performs D/A conversion on the digital data in accordance with the pulse signal P3', ultimately restoring the original composite color video signal as shown in FIG. 5(E), and outputting it to two output terminals. Output to.

On the other hand, when the dropout detector 19 detects that a dropout has occurred in the incoming reproduction No. 45,
A detection signal is generated and output to the control device 24. In this case, the control 2Il device 24 R
It is read from AM27 and output to D/A conversion 12B. The [)/A converter 28 performs D/A conversion on the incoming digital data from two days ago, and outputs it to the output terminal 29 as a composite color video signal for the current horizontal scanning period.

In this way, by grouping the same-phase data in the composite color video signal, the composite color video signal becomes as if it were a component signal. The disadvantages are eliminated and the following advantages are obtained.

■ The band of the measurement signal is generally 4.2MHz,
On the other hand, the video signal transmission band by the device of the present invention is, for example, N
In the case of TSC system, it is 5.4MH2 or more, so VTR
The luminance signal can be completely restored during playback.

(2) Since there are no subcarrier components with large energy in the high frequency range, the method of the present invention is suitable for FM transmission.

■ Enables stable color signal transmission against time axis errors (jitter).

(2) A special color process circuit is not required for both the recording and reproducing systems of the VTR.

■ Supports guard panless recording using only the azimuth head.

■ - Frequency recording is possible, so there is no spurious interference.

■ Since there is no Y/C separation, high resolution can be obtained (N
In the case of the TSC method, for example, the number of scanning lines is 430)
In addition, a time base corrector is used to obtain a composite color video signal that ensures interleaving.

Note that the signal processing of the apparatus of the present invention may be performed by a digital circuit as shown in FIGS. 1 and 2, and for example, a charge-coupled delay element (COD delay element) may be used.

Furthermore, like the NTSC system, the PAL system also has the regularity of in-phase sampling points for color subcarriers, so it goes without saying that the device of the present invention can also be applied to composite color video signals of the PAL system. .

Effects of the Invention As described above, according to the present invention, a composite color video signal is converted into the pseudo component signal and recorded on a magnetic recording medium, and the reproduced pseudo component signal from the magnetic recording medium is converted into the original composite color video signal. Since it is restored to Since there are no subcarrier components with large energy in the 5 band, recording and reproducing by FM modulation becomes easy, and furthermore, the amount of information contained in the composite color video signal can be sufficiently reproduced and restored.

[Brief explanation of drawings]

1 and 2 are block system diagrams showing an embodiment of the recording system and reproducing system of a color video signal magnetic recording device and a magnetic recording/reproducing device according to the present invention, respectively, and FIGS. 3(A) to (E)
and FIGS. 5(A) to 5(E) are diagrams for explaining the operation of the block systems shown in FIGS. 1 and 2, respectively, and FIG. 4 is a diagram of an example of a tape format according to the apparatus of the present invention. 1... Composite color video signal input terminal, 2... Automatic gain control circuit (AGC circuit), 3.21... A/D converter, 4, 24... Timing pulse generation circuit, 5゜2
3...Phase locked loop, 6,24...
υIt[l device, 7, 27...Random access
Memory (RAM), 8.28...D/A converter, 9.
...Emphasis circuit, 10...FM modulator, 11.
...Recording amplifier, 12...PCM audio signal input terminal,
13° 14... Preamplifier, 15... Switch circuit, 16... Switching signal input terminal, 17... Equalizer circuit, 18... FM demodulator, 19... Dropout detector, 20...・・pcMg voice signal ratio signal output terminal・
...Crystal oscillator, 26...Clock circuit, 29...
Composite color video signal output terminal, H+, H2...Rotating head. Patent applicant: Japan Victor Co., Ltd. Raku3 Figure: 0% sail 0 FM support corner

Claims (3)

[Claims] (1) Color subcarrier frequency f_s_ of composite color video signal
pulse generating means that generates and outputs sampling pulses and control signals that are n times c (where n is a natural number), and an A/D converter that samples the composite color video signal with the sampling pulses and outputs sampling data. and,
The sampling data is converted into a total of n groups of data in which one group is sampling data of each sampling period 1/f_s_c that has the same phase with the color subcarrier of the composite color video signal within one horizontal scanning period. , storage means for arranging and reading out the n groups of sampling data in series for each group in units of one horizontal scanning period in accordance with the control signal; and converting the output data of the storage means into an analog video signal and outputting it. 1. A color video signal magnetic recording apparatus comprising: a D/A converter; and a recording means for frequency modulating an output analog video signal of the D/A converter and recording it on a magnetic recording medium. (2) Color subcarrier frequency f_s_ of composite color video signal
a first pulse generating means for respectively generating and outputting a first sampling pulse and a first control signal of n (where n is a natural number) times c, and sampling the composite color video signal with the first sampling pulse; a first A/D converter that outputs sampling data; and a sampling period of 1/f that makes the sampling data have the same phase with the color subcarrier of the composite color video signal within one horizontal scanning period.
The sampling data of each _s_c is converted into n groups of data in total as one group, and the n groups of sampling data are serially processed for each group in units of one horizontal scanning period according to the first control signal. a first storage means for arranging and reading;
a first D/A converter that converts output data of the first storage means into an analog video signal and outputs the analog video signal;
A recording means for frequency-modulating the output analog video signal of the converter and recording it on a magnetic recording medium, a reproducing means for outputting a reproduced signal obtained by reproducing and demodulating a recorded signal on the magnetic recording medium, and the reproduced signal. a second pulse generating means for respectively generating and outputting a second sampling pulse and a second control signal of n times the color subcarrier frequency f_s_c; n
a second A/A that restores and outputs the group sampling data;
a D converter; and the second A/D converter in response to the second control signal.
a second storage means for repeatedly extracting and reading each sampling data one group at a time from the n groups of sampling data from the converter; and digital-to-analog conversion of the output data of the second storage means. and a second D/A converter for restoring and outputting the original composite color video signal. (3) The second storage means writes the n groups of sampling data from the second A/D converter based on the horizontal synchronization signal in the output reproduction signal of the reproduction means; Sampling data is read using a separately generated frequency n.
- The color video signal magnetic recording and reproducing apparatus according to claim 2, characterized in that the color video signal magnetic recording and reproducing apparatus is configured to perform the recording based on the f_s_c reference clock signal.