JPS62179292A - Video signal processor - Google Patents

Abstract

PURPOSE:To reproduce and display a color picture having the high picture quality by individually outputting at least three signals of the optional combination of a luminance signal, a primary color signal and a color difference signal. CONSTITUTION:The output signal of a voltage control type crystal oscillator (VXO) 22 is branched, is supplied to a phase adjusting device 53 to apply the phase adjustment and two output signals having the phase difference of 90 deg. to each other from the phase adjusting device 53 to an R-Y demodulation circuit 51 and a B-Y demodulation circuit 52 separately as demodulation reference carriers. Thereby, from the R-Y demodulation circuit 51, the color difference signal R-Y of the demodulated base band is taken out and from the B-Y demodulation circuit 52, similarly, a color difference signal B-Y of the demodulated base band is taken out. These color difference signals (R-Y) and (B-Y) are respectively supplied to a matrix circuit 54 and outputted to output terminals 60, 61. The two types of the color difference signals and a reproduced luminance signal from a deemphasis circuit 7 are supplied to the matrix circuit 54 to form the three primary color signals and output to output terminals 55, 56, and 57, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a video signal processing device, and in particular to a recording medium in which a suspended color signal is frequency-converted to a frequency lower than the frequency-modulated i-mode signal band and recorded. The present invention relates to a video signal processing device suitable for obtaining a high-quality reproduced color image when reproducing a video signal from a video signal.

BACKGROUND OF THE INVENTION FIG. 5 shows a block diagram of an example of a conventional video signal processing device. In the figure, a recolor video signal is recorded on a recorded magnetic tape 1 in a VTR using an existing low frequency conversion color recording/reproducing system. This recorded color video signal is obtained after the luminance signal is frequency modulated, and the carrier color signal is frequency-converted to an empty frequency region below the band of the frequency-modulated luminance signal, resulting in a low-frequency converted carrier color signal. , the frequency modulated luminance signal and the low frequency converted carrier color signal are frequency division multiplexed, respectively.

The magnetic head 2 reproduces the frequency division multiplexed signal from the recorded magnetic tape 1, and supplies it to a high-pass filter (hereinafter referred to as HPF) 4 and a low-pass filter (hereinafter referred to as LPF) 5 through a preamplifier 3, respectively. The reproduced frequency modulated luminance signal separated into P waves by the HPF 4 passes through an FM demodulator 6 and a de-emphasis circuit 7, respectively, and is converted into a reproduced luminance signal and supplied to a synchronization separation circuit 8 and an adder 24, which will be described later.

On the other hand, the LPF5 allows the minute Il! IP wave playback low j-
The converted carrier color signal is supplied to the balanced modulator 10 through the ACC circuit 9, where it is converted into a reproduced carrier color of the original phase in the original band as described later, and then subjected to burst attenuation as described later. Vessel 11. Bandwidth filter (hereinafter referred to as BPF) 12
and a comb filter 13, and are supplied to a burst extraction circuit 14 and a sieve 24, respectively.

Here, to explain the operation of converting the low-pass conversion carrier color signal to the reproduced carrier color signal, the horizontal synchronization signal of frequency fH having jitter, which is separated from the reproduced luminance signal by the synchronization separation circuit 8, is transferred to the burst sampling circuit. The signal is supplied to the phase comparator 15 to perform a gate operation for extracting the color burst signal from the reproduced conveyed color signal.

As a result, the phase comparator 15. Voltage controlled oscillator (hereinafter referred to as vC)
vC016 in the well-known phase-locked loop (P L L ) consisting of a counter 16 and a counter 17
Therefore, the frequency 1i1(1
A signal of 60-fH is extracted.

The PS processing circuit 18 receives 1 from the signal from this VCO 16.
A frequency of 40.degree. for a known phase shift process (PS process) in which the phase shifts in a fixed direction by 90 degrees every horizontal scanning period (1H), and the phase shift direction is reversed every field. A signal of fH (which is equal to the chrominance subcarrier frequency of the low-pass converted carrier chrominance signal) is generated and supplied to the balanced modulator 19.

On the other hand, phase comparison P! 20 is the color subcarrier frequency fs of the standard color video signal to be reproduced, which is supplied from the reference crystal oscillator 21 (therefore, in the case of the NTSC system, it is 3.57
For example, 4.4 in the case of 9545 MH2, PA L method.
a signal with a frequency fS equal to 33679 MHz);
The phases of the reproduced color burst signals of the frequency fs supplied from the burst 1 sampling circuit 14 are compared, and the error voltage corresponding to the difference between them is calculated using a municipal control all-type crystal oscillation signal (hereinafter referred to as XO). 22, and its output oscillation frequency is varied by υ1m.

As a result, the output signal of the VXO22 has the frequency fs
, and a signal that responds to the phase shift of the reproduced color burst signal, A P C (Auto@aticPha
se Control) is supplied to the balanced modulator 19 as the output signal of the loop.

The balanced modulator 19 receives the AFC (
Eight autoa+atic Frequency Cont
rol) By performing balanced modulation (frequency conversion) of the signal of frequency 40 fH-+ by the loop and the signal of frequency afs by the APC loop from vx022, and passing the resulting signal through BPF24, the frequency fs+4
A signal of 0-f+-+ is generated. The output signal of this BPF 24 is subjected to PS processing from the ACC circuit 9, and the color 117IIl! The reproduced low-pass converted carrier color signal having a transmission frequency of 40·fH is balanced modulated (frequency converted) by a balanced modulator 10, and then passed through a burst attenuator 11 and the BPFI 2 extracts the frequency component of the difference. As a result, the original color 0111 is returned from BPF12.
At one transmission frequency fs, a reproduced carrier color signal from which frequency shift components and phase shift components have been removed, and from which PS processing has also been removed, is extracted.

In addition, when recording, the color burst signal level should be set to 6, for example.
When the color burst signal is enhanced and recorded, only the color burst signal level is attenuated by 6tf3 by the burst attenuator 11 and returned to the original level, thereby improving the S/N ratio of the color burst signal. Are known.

The reproduced carrier color signal from which crosstalk components from adjacent tracks have been removed by the comb filter 13 is added to the reproduced luminance signal in an adder 25 to form a reproduced composite color video signal, and then sent to an amplifier. 26 and is output to the output terminal 27.

The above-mentioned reproduced composite color video signal is supplied to the input terminal 28 of the television receiver 30 shown in FIG. Thereafter, the reproduced carrier color signal is supplied to the matrix circuit 33 through the color demodulation circuit 32, and the reproduced carrier color signal is
The OI signal is directly supplied to the matrix circuit 33, where it is subjected to matrix processing. As a result, the matrix circuit 33
The extracted three primary color signals are supplied to a cathode ray tube 34, where a reproduced color image is displayed.

Problems to be Solved by the Invention However, the above-mentioned conventional device outputs a composite color video signal in which a reproduced luminance signal and a reproduced carrier color signal are superimposed, respectively, to the television receiver 30 for displaying a color image. Therefore, it is necessary to separate the reproduced luminance signal and the reproduced carrier color signal from this composite color video signal again in the television receiver 30, and the frequency characteristics and phase characteristics of the signal are likely to deteriorate in filters, etc. for this purpose. , this Y/Cf
) When Ill is incomplete, there is a problem that interference such as cross color appears. Furthermore, since conventional devices combine the reproduced luminance signal and the reproduced carrier color signal and output them in the form of a composite video signal, interference occurs between the two signals due to the combination, and the frequency interleave relationship between the two signals is destroyed. Particularly in recent high-performance preview image receiving systems, there has been a problem in that mutual interference is often noticeable on the screen.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a video signal processing device that solves the above problems by reproducing and outputting a reproduced luminance signal and a reproduced carrier color signal in the form of component signals without combining them. .

Means for Solving the Problems The video signal processing device according to the present invention reproduces a frequency division multiplexed signal from a recording medium, and separates a frequency modulated g-degree signal and a low-frequency converted carrier color signal from the signal into P waves. means, demodulating means for obtaining a reproduced luminance signal, frequency converting means for obtaining a reproduced carrier color signal, reproduced carrier color signal and reproduced luminance signal.
The apparatus includes means for demodulating one or both of the different types of primary color signals and the two types of color difference signals, and outputting at least three types of signals from among these signals and the reproduced luminance signal.

Of the reproduced frequency-modulated luminance signal and the reproduced low-pass conversion carrier color signal that are reproduced from the working recording medium and separated, the reproduced frequency-modulated luminance (n) is demodulated by the demodulation means to become a reproduced luminance signal. Further, the reproduced low-band converted carrier color signal is returned to the original band reproduced carrier color signal by the frequency conversion means.The reproduced rli degree signal and the reproduced carrier color signal are respectively supplied to the output means, After being converted into two types of primary color signals and/or two types of color difference signals,
At least three types of signals are output from among the primary color signals, nine color difference signals, and reproduced luminance signals.

In addition, the above-mentioned) 3 means is a base for demodulating two types of color difference signals from the reproduced carrier color signal. As the second wave transmission, a signal of a substantially constant frequency used for frequency conversion by the frequency conversion means is also used.

Furthermore, the output means is configured to output two signals demodulated from the reproduced carrier color signal.
By adjusting the level of different color difference signals, there is provided means for compensating for the level enhancement valve of the color burst signal during recording.

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

FIG. 1 shows a block system diagram of a first embodiment of the present invention.

In the figure, the same components as those in FIG. 5 are denoted by the same reference numerals, and the explanation thereof will be omitted. In FIG. 1, a comb-shaped filter 1
The reproduced carrier color signal extracted from 3 is sent to the R-Y demodulation circuit 5.
1 and BY demodulation circuit 52, respectively.

On the other hand, as mentioned above, the VXO 22 outputs a signal for generating a frequency conversion signal for returning the reproduced low-frequency converted carrier color signal to the reproduced carrier color signal of the original band. The signal frequency is the reproduced color burst signal and the reference crystal ffi! ! This is the color subcarrier frequency fS or a frequency extremely close to it, depending on the phase difference with the output signal of No. 21.

Therefore, in this embodiment, the output signal of this VXO 22 is branched and supplied to the phase adjuster 53, where the R-Y axis, B
- Perform the necessary phase adjustment to perform demodulation on the Y axis,
2 having a phase difference of 90° from each other from the phase adjuster 53
The two output signals are separately supplied to the RY demodulation circuit 51 and the BY demodulation circuit 52 as a demodulation base Q=carrier wave.

As a result, the demodulated baseband color difference signal RY is taken out from the R-Y demodulation circuit 51, and the baseband color difference signal g which is similarly demodulated is taken out from the B-Y demodulation circuit 52.
B-Y is taken out. These color difference signals (R-Y) and (B-Y) are respectively supplied to the matrix circuit 54 and output to output terminals 60 and 61.

The matrix circuit 54 is supplied with the above two types of color difference signals and the reproduced luminance signal from the de-emphasis circuit 7, respectively.
From these, well-known matrix processing is performed and the red signal (
R), green signal (G) and blue signal (B) are generated and output separately to output terminals 55, 56 and 57, and a composite signal @ (SYNC) is output to output terminal 58.
Output to.

Some recent television receivers are equipped with video input terminals for three primary color signals, and others are equipped with video input terminals for color difference signals and luminance signals. etc., it is possible to display a high-quality color image. That is,
The reproduced video signal is a component signal format in which three primary color signals or a luminance signal and two types of color difference signals are transmitted separately and simultaneously without being combined, so it is not possible to combine the luminance signal and the carrier color signal as in the past. No mutual interference occurs at all.

Next, a second embodiment of the present invention will be described with reference to the block diagram shown in FIG. In the figure, the same components as in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted. In this embodiment, the output signal of the reference crystal oscillator 21, which oscillates and outputs a frequency equal to the color subcarrier frequency fs, is supplied to the phase adjuster 62, and after phase adjustment there, the R-
It is characterized in that it is supplied to the Y demodulation circuit 51 and the BY demodulation circuit 52. According to this embodiment, the reference crystal oscillator 21, which outputs a signal serving as a reference signal for frequency conversion to obtain a reproduced carrier color signal, can also be used for generating a carrier wave for color demodulation, so that the circuit configuration can be integrated into the cylinder. Become.

Next, a third embodiment of the present invention will be described with reference to the block system diagram shown in FIG. In the figure, the same components as in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted. In this embodiment, as shown in FIG. 3, the reproduced color burst signal taken out from the burst extraction circuit 14 is branched into two, one being supplied to the phase comparator 20 as in the conventional case, and the other being supplied to the phase comparator 20 in the same way as in the conventional case. The signal is supplied to a newly provided phase comparator 64, where the phase is compared with the output signal of the VXO 65.

The phase comparator 64 and the VXO 65 constitute a second phase-locked loop (PLL), and the VXO 65 sends a signal with a frequency equal to or very close to the color subcarrier frequency fS that is phase-locked to the reproduced color burst signal to the phase adjuster 53. is output.

In this embodiment, the APC for the demodulated carrier wave during color demodulation is
This is a new loop. RY demodulation circuit 51
．． 8-Y demodulation circuit 541 phase comparator 53. An existing IC can be used as is for the circuit section consisting of the matrix circuit 541, phase comparator 64, and VXO 65.

Next, a fourth embodiment of the present invention will be described with reference to a block system diagram shown in FIG. In the figure, the same components as those in FIG. In the embodiment shown in FIGS. 1 to 3, the frequency conversion circuit unit that returns the reproduced low-pass conversion carrier color signal to the original frequency band converts both the error signals of the APC loop and the AFC loop into the balanced converter J4. 19
However, in this embodiment, both the error signals of the ΔFC loop and the APC loop of the phase comparators 15 and 20 are sent to the adder 67. and add the sum signal to a single VC
This is applied to a VTR configured to variably control the oscillation frequency of O16.

The output oscillation frequency of the VCO 16 is supplied to a balanced modulator 19 through a PS processing circuit 18, where it is balanced modulated with a signal from an oscillator 68 having a frequency equal to the normal color subcarrier frequency fS.

The output signal of this oscillator 68 is also supplied to a phase comparator 20 and further supplied to a phase adjuster 69, where each
Shun whose 0° phase is different and adjusted to a predetermined phase,
The signal is supplied to the RY demodulation circuit 51 and the BY demodulation circuit 52 as reference carrier waves for demodulation, respectively.

Note that although the frequency stability of the reference crystal oscillator 321 and the oscillator 68 in J5 in each of the above embodiments is degraded, an oscillator other than a crystal oscillator using an LC or the like may be used.

Further, the VXO 22 may also be a vCo without a crystal resonator whose frequency stability is lower than that of the vXO. The reason is that the base signal of the frequency conversion signal to be supplied to the balanced modulator 1o and the demodulation reference carrier wave supplied to the RY demodulation circuit 51 and the BY demodulation circuit 52 are common. This is because it is configured as follows. In other words, in the past, the process of obtaining a reproduced carrier color signal in a VTR and the process of performing color demodulation in a preview receiver were performed in separate systems, so the color subcarrier frequency of the reproduced carrier color signal was strictly controlled at a high level. Although it was required that the color subcarrier frequency accurately match the regular color subcarrier frequency, in the present invention, since the above image processing is performed in the same system, it is not necessary to exactly match the regular color subcarrier frequency. be.

If an oscillator other than a crystal oscillator or a VcO is used instead of a VXO, the circuit becomes inexpensive.

Further, in each of the above embodiments, the burst attenuator 11 is not provided, regardless of whether or not the color burst signal level is enhanced during recording. This means that even if this circuit is omitted,
This is because even if the color burst signal level is enhanced during recording, correct color reproduction can be achieved by having means for adjusting the level of the output color difference signal in the demodulation circuits 51 and 52. If only the color burst signal level is attenuated by 6 dB as in the conventional method, the relative phase relationship between the color burst signal and the reproduced carrier color signal of the other video periods is likely to shift, resulting in a change in hue. According to each of the embodiments, such inconveniences can be prevented from occurring.

However, even if the purse 1 to the attenuator 11 are provided in the present invention, the above-mentioned disadvantages are likely to occur, but of course there is no problem.

Note that the present invention is not limited to the above-described embodiments, and the output signal may be a combination of a luminance signal and two types of color difference signals, or a combination of three primary color signals; At least three types of signals, such as a combination of a luminance signal and two types of primary color signals, or a combination of three types of color difference signals, may be output in a component format.

Effects of the Invention As described above, according to the present invention, at least three signals in any combination (for example, three primary color signals, or a luminance signal and two types of color difference signals, etc.) of a luminance signal, a primary color signal, and a color difference signal can be used. Since they are output separately, compared to conventional devices that output composite color video signals, there is no need to separate Y/C again within the television receiver, and there is no signal deterioration due to Y/C separation. Furthermore, there is no mutual interference due to the combination of three signals.
Since there is no interference such as cross color caused by incomplete /C separation, high-quality color images can be reproduced and displayed, and the reproduced low-frequency conversion carrier color signal can be converted to the original band within the same device. Since the frequency conversion signal for returning the reproduced carrier color (+'i) and the reference carrier wave for demodulating the reproduced carrier color signal are derived from the same signal, the circuit configuration is integrated into a cylinder, and the conventional device is It does not require high-precision jitter correction accuracy, so it can be used with inexpensive oscillators other than crystal oscillators or
It is possible to use a cheaper CO other than O, in which case J: can be constructed at a lower cost.Furthermore, even if the color burst signal level is enhanced at the time of distribution, the demodulated color difference signal q By adjusting the level, it is possible to compensate for the level enhancement power, thereby preventing the occurrence of hue changes that occur in conventional devices that attenuate the level of only color burst signals. be.

[Brief explanation of drawings]

1 to 4 are block system diagrams showing each embodiment of the device of the present invention, FIG. 5 is a block system diagram showing an example of the conventional B position, and FIG. 6 is a diagram showing the main points of a general television receiver. FIG. DESCRIPTION OF SYMBOLS 1...Magnetic tape, 4...High-pass filter (HPF) for frequency-modulated luminance signal separation, 5...Low-pass filter (LPF) for low-pass conversion carrier color signal separation, 6...FM role Modulator, 10.19... Balanced modulator, 21... Reference crystal oscillator, 51... R-Y demodulation circuit, 52... B-Y
Demodulation circuit, 53.62.69... Phase adjuster, 54.
...71-RiX circuit, 55-57...Primary color signal output terminals, 5...Reproduction luminance signal output terminals, 60.61.
... Color difference signal output terminal, 61 ... Phase comparator, 65.
... Voltage controlled crystal oscillator (VX○), 67... Kawaguchi Ki, 68... Oscillator.

Claims (3)

[Claims] (1) Reproducing a frequency division multiplexed signal consisting of a frequency modulated luminance signal and a low-pass converted carrier chrominance signal occupying a band lower than the frequency-modulated luminance signal from a recording medium in which the frequency division multiplexed signal is recorded; means for separating and filtering the frequency modulated luminance signal and the low-pass conversion carrier chrominance signal; demodulation means for demodulating the separated frequency-modulated luminance signal to obtain a reproduced luminance signal; and the separated low-pass conversion means. a frequency conversion means for returning the carrier color signal to a reproduced carrier color signal of the original band; and obtaining one or both of three types of primary color signals and two types of color difference signals from the reproduced carrier color signal and the reproduced luminance signal. A video signal processing device comprising: output means for outputting at least three types of signals from among the primary color signal, the color difference signal, and the reproduced luminance signal. (2) Demodulating the two types of color difference signals from the reproduced carrier color signal in the output means from a signal of a substantially constant frequency used for frequency conversion with the low-pass converted carrier color signal in the frequency converter; 2. The video signal processing device according to claim 1, wherein the video signal processing device generates a reference carrier wave. (3) The color burst signal in the low-pass converted carrier color signal is level-enhanced during recording, and the output means adjusts the levels of the two types of color difference signals demodulated from the reproduced carrier color signal, 2. The video signal processing apparatus according to claim 1, further comprising means for compensating for the color burst signal level enhancement.