JPS607289A - Color signal processing system of video reproducing device - Google Patents

Abstract

PURPOSE:To obtain a color signal of good quality by extracting an output pulse of a part corresponding to a color burst signal and extracting a color burst signal for phase detection from a reproducing color signal by means of the output pulse to increase the noise resistivity. CONSTITUTION:Both a, b signals are impressed to an input terminal of an AND circuit 20, then an AND pulse (c) of both the signals is produced at an output terminal and impressed to a terminal T of a flip-flop 21. This flip-flop 21 is set by the front edge of the pulse (c) and reset by the trailing edge of the signal pulse (b) and outputs a pulse signal (d). That is, when the signal (a) exists, the pulse output (d) having the same width as that of the signal pulse (b) risen with a delay is obtained. Thus, in using a pulse 18 as the signal (a) and a signal 17 as the signal (b), a pulse of a position corresponding to the burst signal in the signal 17 risen at the presence of the pulse 18 is extracted as a pulse 19. This output signal pulse 19 is impressed to a burst signal extracting circuit 7 as a gate signal so that the burst signal is extracted effectively from the reproduced color signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color signal processing system for a video II+ raw device such as a video disc, and in particular corrects jitter due to time axis fluctuations in a color signal contained in a video signal obtained from a rotating video disc. The present invention relates to a color signal processing system.

Conventionally, in some types of video disk playback devices, changes in capacitance between a two-rotation video disk and a pickup needle are detected, and then appropriate signal processing is performed to obtain a video signal or an audio signal f. Jitter is included in the reproduced signal due to the eccentricity of the rotating video disk itself, distortion in one plane, uneven rotation of the motor that rotates the video disk, and the like.

For this reason, conventional video disc playback devices include a time axis correction system to absorb jitter components.

1 for the jitter component included in the color signal.

Extract only the color burst signal fr from the student color signal and calculate the automatic phase of this color burst signal? ! The low range of jitter was measured by the ABC loop that performs IJ correction. However, with the conventional APO loop, it is not possible to extract the burst signal from the reproduced color signal with good FR. The problem with the reproduced color signal, which is the output of the loop, is that noise is mixed in, making it impossible to obtain a high-quality color signal.

FIG. 1 is a block diagram showing a color signal processing system of a conventional embedded subcarrier type video disc playback device, in which (1) is a disc signal pickup section, (2) is an FM detection circuit, and (3) is a frequency conversion circuit. ,(
4) is a bandpass filter, (5) is a comb-shaped filter, and (6) is a bandpass filter.
1D hammered ゛ρIP product (AOO)
circuit, (7) is a burst signal extraction circuit, (8) is a phase detection circuit, (9) is a voltage controlled quartz crystal oscillation (VC)
xO) circuit.

OI is a reference frequency crystal oscillation (XO) circuit, (Ill is a synchronous separation circuit, a is a burst sampling signal generation circuit, 0
The terminal is the output terminal.

In the embedded subcarrier type video tisf.

The color signal has a subcarrier wave number of 3.579545 MHz (hereinafter this frequency will be referred to as fo
), but is converted to a certain frequency f1,
It is F'M modulated and recorded together with the luminance signal.

The disk signal pickup section fil detects a change in the static capacitance between the rotating video recorder and the pickup needle, converts this into an electrical signal and outputs it as an FM signal, and this FM signal is sent to the FM detection circuit (2). Detect and obtain video signal. This signal consists of a luminance signal component/color signal with a frequency of Xf1. This video signal is applied to a frequency conversion circuit (3),
It is heterodyne detected with the signal of the frequency fl-1-fQ), and is detected by the bandpass filter (4) as (f1+fo)
-f1=fo Only the signals of nearby frequencies are extracted, and the luminance signal component is removed by a rectangular filter (5) having a pass characteristic at frequencies that are odd multiples of 7 of the horizontal scanning frequency, and only the color signal is sent to the ACjC circuit. (6), the level is set to a constant level, and 44+ raw power error signals are obtained at the output terminals α.

This signal and a separately processed luminance signal are added to form a reproduced color video signal H. The burst signal (reference color sub-carrier liquid portion) of this reproduced color signal is extracted by the blade signal of the burst signal extraction circuit (7) and applied to the phase detection circuit (8). )in,
Phase detection is performed using the continuous wave signal of the reference frequency fo from the XO circuit 4.

The V CX O circuit (9) is designed to oscillate at a frequency according to the input voltage, and the center frequency is (fo+ft
), and this blade signal is applied to the frequency conversion circuit (3) to obtain an APO reproduced color signal. The video signal t, which is the output signal of the FM @ wave circuit (2), is also applied to the synchronization separation circuit 00,
The output signal is applied to the burst sampling signal generation circuit 0. In this circuit, a signal is generated at the burst signal position of the r) color signal by copying or ringing, and this signal is applied to the burst signal sampling circuit (7), only during the signal mark 7JII period. A color burst signal is extracted by passing the reproduced color signal.

In this way, the phase control is carried out so that the phase of the color burst signal is always synchronized with the output signal of the reference frequency oscillation circuit section, so that the output terminal side.

A color signal with reduced color jitter can be obtained. However, in order to absorb all the jitter in the color signal and obtain a high-quality color signal, it is important to extract the jitter information of the color signal well. The color signal jitter is included in the color burst signal, and the color burst signal does not include phase changes other than jitter, so the burst signal extracted by the burst signal extraction circuit (7) in Figure 1 is The output signal of the phase detection circuit (8) that phase-detects the color burst signal is information on the jitter of the color signal. The phase detection circuit (8) generally outputs the integral 14 of the two-phase comparison circuit in order to reduce the influence of noise contained in the test signal, and this 1744 points are If the burst signal is input to the 3-wave circuit (El), it is better to have a wide width.Moreover, the color signal other than the burst, which includes phase change other than jitter, is input to the 2-phase detection circuit (8). As mentioned above, the no(-st) signal marked on the 1-phase detection circuit (8) is
++1 Nama No 7 Rai 1f, which is the deba of circuit (6),
The burst signal sampling circuit (7) performs parsing and sampling signal generation circuit (which is obtained by gated by the output of one side,
This burst sampling signal generating circuit is generally constructed of a multi-minute circuit or linking circuit 41' as described above, and generates the cutting gate signal.

It was the circuit section that provided the appropriate width for the reproduced burst signal. Furthermore, if the position of the burst signal with respect to the synchronization signal was flickered by the disc, an appropriate burst extraction gate signal could not be obtained, and a high-quality color image could not be obtained.

This origin j is considered to be six points such as 2 or more,
The present invention will be explained in detail below with reference to FIGS. 2 and 3. FIG. 2 is a block diagram showing a color signal processing system for a video disk reproducing apparatus which is an embodiment of the present invention, and FIG. 3 is a signal waveform diagram of each part of this system.

In the figure, (11 to (+31) are the same circuits as in Figure 1, and the same - or equivalent parts are given the same symbols.I is the same 1111 detection circuit, and H is the second burst sampling signal. This is a generation circuit. Each I of the synchronous detection circuit is AC!(,
,! The phase of the output of the crystal oscillation (XO) circuit a1 is shifted from α→ to the phase at which the detected output is maximum, and synchronous detection is performed. The output of the synchronous detection circuit α4) is a signal in which a pulse output always occurs in the burst signal portion, for example as shown in FIG. −
10,000 burst sampling signal generation circuit (+4).

At the trailing edge of the synchronous signal from the synchronous separation circuit (fil), a pulse (Fig. 3 (III)) wider than the rising burst signal is generated, and this pulse 0 and the output (Iη) of the synchronous detection circuit ++4 are The output of the burst sampling signal generation circuit (l is marked 11. In this circuit, the output of the first wave detection circuit 04) (only the part (i) corresponding to the burst signal in 11 is output as pulse 01 by pulse 08. This cycle 1.jiiO→ can be realized, for example, using the space shown in Fig. 4. In the figure, slope is an AND circuit, and 0)) is a T free run block. Its operation is shown in the waveform shown in Fig. 5. As shown.

Both signals a and b are input to the input terminal of the AND circuit (a) [
1, an AND pulse C of these two signals is generated at its output terminal, and a mark /jl+ is generated at the T terminal of the flip 70 (01).
be done. This fritz 770tsu7'C1υ is set at the leading edge of the pulse C to the T terminal at the time of reset, and reset at the trailing edge of the signal pulse b to the R terminal -\ at the time of setting.
The pulse signal shown in Figure d is used. That is, when the signal rI exists, a pulse output d having the same width as the signal pulse b that rises from the signal rI is obtained. Therefore, this No. 16, a.
If the pulse o1 in the figure is used as a signal and the signal ((η) in Figure 3 is used, the pulse at the position corresponding to the burst signal in the signal θ that rises while the pulse 9 exists is extracted as the pulse oC! Therefore, the second burst sampling signal generating circuit (+!il) outputs the burst I/!il of the reproduced color signal.
This output signal pulse ←1 is applied to the burst signal extraction circuit (7) as a gate number 1-41, and the burst signal is effectively extracted from the raw error signal. You can take it.

Since this IJJ4 jrihX is performed as described above, only the burst signal can be extracted stably even if the position of the I inburst signal changes depending on the disk or even if the width of the burst signal changes. Therefore, the C-phase detection has the effect of increasing the noise resistance and making it possible to obtain a color standard.

In the above description of the present invention, a video disc playback device has been used as an example, but other systems such as a video disc playback device (
Of course, it can also be used for +4 production equipment.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a color signal processing system of a conventional videodisk playback device, and FIG. 2 is a block diagram showing a color signal processing system of a video disk playback device, which is a first embodiment of the present invention. , Figure 3 shows the signal waveforms of each part of this system as shown in 1. Fourth
Figure 19 shows an example of the second burst sampling signal generation port bw in Figure 2, and Figure 5 shows the signal waveforms of each part. circuit, (3
) is a frequency a conversion circuit, (4) is a bandpass filter, (51
tJ,'< L-form-y irta, telr, []
mh color v bell l1I11 increase 'l': □'□ times j'ij. (7) is the perstoy g extraction circuit lf. (8) is the phase phase wave circuit. (9) is the voltage 1filJ @u crystal oscillation circuit, (1!
'It: J, reference frequency crystal oscillation circuit, al) is the synchronous component h1 (circuit, θ is the burst sampling signal generation circuit, αto is the output mizuki, θ is the synchronous detection circuit, α1 is the second burst sampling signal The generation circuit is as follows. In the figure, the corresponding parts are indicated by the same reference numerals 7. Agent: No'a Taoiwa (and 2 others) Figure 3 Figure 4

Claims (1)

[Claims] A reproduced color signal is extracted by heterodyne detection of the detected video signal using the voltage-controlled oscillation circuit output signal. A video in which a color burst signal is extracted from this color signal, phase detection is performed on this color burst signal using a reference frequency oscillation circuit output signal, and this phase detection output signal is used to control the frequency and phase of the oscillation circuit on the voltage side. In a color signal processing system for reproduction equipment, a synchronizing signal is separated from the detected video signal, and a pulse signal at a color burst signal position of the reproduced color signal is generated from this signal. Using this pulse signal, an output pulse corresponding to the burst signal is extracted from the output signal obtained by synchronously detecting the reproduced color signal with the output signal of a predetermined phase of the reference frequency oscillation circuit, and this output pulse is used for the phase detection. A color signal processing system for a video playback device, characterized in that a color burst signal is extracted from the reproduced color signal.