JPH01253386A - Chrominance signal reproducing and processing circuit - Google Patents

Abstract

PURPOSE:To limit the color inversion noise produced on a picture when a track jump is made at the time of high-speed reproduction, etc., so as to ameliorate the deterioration of picture quality by providing a color difference discriminating circuit which controls outputs to a fixed quantity synchronously to a track jump pulse. CONSTITUTION:Line sequential color difference signals which are produced by making two kinds of color difference signals line sequential at every one horizontal scanning period are recorded on an optical disk 1 at a rate of one frame quantity per one track. A laser pickup 2 detects the recorded signals and a preamplifier 3 amplifies the reproduced signals, and then, a low-pass filter(LPF) 4 separates chrominance components from the reproduced signals. A 1-H delay device 6 causes the line sequential color difference signals FM-modulated by an FM demodulator 5 to delay by one H. A circuit 7 for making two kinds of signals simultaneous makes the two kinds of color difference signals of non-delayed signals and 1-H delayed signals simultaneous with each other in time in accordance with the output of a color difference discriminating circuit 10 and outputs the simultaneous signals. A disk detector 11 outputs a tracking error signal. A track jump pulse generating circuit 12 generates a pulse synchronously to a track jump.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides two types of color difference signals in one horizontal scanning period (1H).
The present invention relates to a reproduction processing circuit for a color signal reproduced from an optical disk in which one frame is recorded on one track in a line-sequential manner.

2. Description of the Related Art In recent years, devices for recording and reproducing video signals on magnetic disks, ie, electronic still cameras and reproducing machines, have been put into practical use. In this case, color signals are recorded by line-sequentially converting two types of color difference signals. It is conceivable to use this method as a recording method for optical discs to reproduce moving images. A conventional color signal reproduction processing circuit will be described below with reference to the drawings.

FIG. 4 shows a conventional color signal reproduction processing circuit.

In FIG. 4, reference numeral 1 denotes an optical disk, on which a color difference signal is line-sequentialized, FM-modulated, and recorded together with a luminance signal and an audio signal. A laser pickup 2 detects a recorded signal, and a preamplifier 3 amplifies this signal. 4 is a low pass filter (LPF) that separates the color signal component from the reproduced signal. 5 is an FM demodulator. e is a 1H delay device p, which converts the FM demodulated line sequential color difference signal into 1
H is delayed. 7 is a synchronization circuit, which outputs the non-delayed signal and 1H.
Two types of color difference signals are output from the delayed signal according to the output of the color difference discrimination circuit 1o.

Further, FIG. 5 shows a conventional color difference discrimination circuit. In FIG. 6, 101 is a line-sequential color difference signal input terminal. 2o is a sample hold circuit, input terminal 1o1
The input signal is sampled and held every 1H.

21 is an edge detection circuit, and sample hold circuit 2
Detect the rising edge of the output of o. 22 and 23 are D flip-flops. D flip flop 2
2 clock input (GK) has horizontal synchronization signal input terminal 1.
03, the input horizontal synchronization signal is input, and the positive output (
Q) A signal that repeats high and low levels is output in response to the clock input.

The output of the edge detection circuit 21 is input to the reset input (R), and the positive output (Q) is controlled to be at a low level when the edge detection signal is input. 26 is an OR gate,
The logical sum of the horizontal synchronizing signal and the output of the mismatch counter 24 is output. Clock input of D flip-flop 23 (G
The output of the OR gate 26 is input to the positive output (Q), and a signal that repeats high and low levels according to the clock input is output from the positive output (Q). The positive output of the D flip-flop 22 and the positive output of the D flip-flop 23 are input to a mismatch counter 24. The mismatch counter 24 outputs a mismatch pulse at the 4th H when two inputs do not match consecutively. 102 is a color difference discrimination signal output terminal, and the output signal of the positive output (Q) of the D flip-flop 23 is outputted as a color difference discrimination signal.

The operation of the color signal reproduction processing circuit configured as described above will be explained below with reference to FIGS. 4, 6, and 6.

First, FIG. 6 shows an example of voltage waveforms at the input/output terminals of each block in FIG. Waveform a is a line-sequential color difference signal inputted from the input terminal 101, and is a color difference signal of 2 woodblocks (B-Y
, RY) are line-sequentialized alternately every 1H with different DC offsets. The waveform is a horizontal synchronization signal input from the input terminal 103. Waveform C is a signal obtained by sample-holding waveform a by sample-and-hold circuit 20. Waveform d is a signal obtained by detecting the rising edge of waveform C by the edge detection circuit 21.

Waveform e is the positive output (Q) of the D flip 70 tube 22. The waveform f is the positive output of the D flip-flop 23 (Q3
It is. The waveform g is the output of the mismatch counter 24, and a pulse is output when the mismatch between the waveform e and the waveform f continues for 4H.

In the above configuration, the reason why the output waveform C of the sample hold circuit 2° is not used as the color difference detection signal is that when noise occurs as shown in Figure 6, the waveform C is distorted due to the influence of the noise. However, the waveform f is not affected by noise at all, and this is because the circuit is resistant to noise. .

Problems to be Solved by the Invention However, the above configuration has the following problems.

During video playback, normally the playback is performed from the inner track along the track groove as shown in FIG. 7(a), but during high-speed playback, jumps to adjacent tracks are repeated as shown in FIG. 7(b). This enables high-speed playback. The figure shows an example at triple speed.

On the other hand, when one frame of video signals is recorded on one track, there are 625H worth of video signals on one track. Therefore, when two types of color difference signals are recorded line-sequentially, different color difference signals exist between adjacent tracks when viewed in the radial direction.

In other words, each time an adjacent track jumps during high-speed playback, the color difference signal is inverted, (R-Y) → (13-Y) or (B-
Y) → (Fl-Y), do.

At this time, as can be seen from the waveform f in FIG. 6, there is a time delay of approximately 6H from ■ to ■ after a track jump occurs until a correct color difference detection signal is output.

Therefore, during high-speed playback, approximately 6 horizontal lines of noise with inverted colors will occur in the same area on the screen.
This had the problem of resulting in a very unsightly screen.

In view of the above problems, the present invention provides a color signal reproduction processing circuit that reduces color noise generated during high-speed reproduction and suppresses deterioration of image quality.

Means for Solving the Problems In order to solve the above problems, the color signal reproduction processing circuit of the present invention includes a track jump pulse generation circuit that generates a pulse in synchronization with a jump to an adjacent track, and a line-sequential color difference signal generation circuit. The color difference discrimination circuit has a function of making a discrimination and inverting the output of the synchronization means in synchronization with the output signal of the track jump pulse generation circuit to output a correct color difference signal.

Effect of the Invention The present invention uses the above-described configuration to invert the output of the color difference discrimination circuit to correct the output when a track jump to an adjacent track occurs, so that the inversion of colors over several lines that occurs on the screen during high-speed playback is corrected. noise 1
It is possible to reduce the image quality to within a line, and it is possible to improve image quality deterioration during high-speed playback.

Embodiment Hereinafter, a color signal reproduction processing circuit according to an embodiment of the present invention will be explained with reference to the drawings.

FIG. 1 shows a block diagram of a color signal reproduction processing circuit in one embodiment of the present invention. In FIG. 1, reference numeral 1 is an optical disk on which a color difference signal is line-sequentialed, FM-modulated and recorded together with a luminance signal and an audio signal. A laser pickup 2 detects a recorded signal, and a preamplifier 3 amplifies this reproduced signal. A low-pass filter (I, PF) 4 separates the color signal component from the reproduced signal. 5 is an FM demodulator. 6 is a 1H delay device, and FMO! The adjusted line-sequential color difference signal is delayed by 1H. Reference numeral 7 denotes a synchronization circuit, which synchronizes and outputs two types of color difference signals from the non-delayed signal and the 1H delayed signal according to the output of the color difference discrimination circuit 10. A tracking detector 11 outputs a tracking error signal. 12 is a track jump pulse generation circuit, which generates a pulse in synchronization with a track jump.

Further, FIG. 2 shows a color difference discrimination circuit in one embodiment of the present invention. In FIG. 2, 101 is a line-sequential color difference signal input terminal. 20 is a sample and hold circuit, which samples and holds the signal input from the input terminal 101 every 1H. An edge detection circuit 21 detects a rising edge of the output of the sample hold circuit 20.

22 and 23 are D flip-flops. A horizontal synchronization signal is input from the horizontal synchronization signal input terminal 103 to the clock input (GK) of the D-clip flop 22, and a signal that returns high and low levels according to the clock input is output from the positive output (Q). be done. Reset input (R)
The output of the edge detection circuit 21 is input to , and the positive output (Q) is controlled to be at a low level when the edge detection signal is input.

25 is an OR gate which outputs the logical sum of the horizontal synchronizing signal and the output of the mismatch counter 24; 26 is an OR gate which outputs the logical sum of the pulse input from the track jump pulse input terminal 104 and the output of the OR gate 26. Clock input (GK) of D flip-flop 23
The output of the OR gate 26 is input to the input terminal, and a signal that repeats high and low levels according to the clock input is the positive output (Q
) will be output. The positive output of the D-flip/70-tube 22 and the positive output of the D-clip/70-tube 23 are input to a mismatch counter 24. The mismatch counter 24 outputs a mismatch pulse at the 4th H when two inputs do not match consecutively. 102 is a color difference discrimination signal output terminal, and the output signal of the positive output (Q) of the D flip-flop 23 is outputted as a color difference discrimination signal.

The operation of the color signal reproduction processing circuit configured as described above will be explained below with reference to FIGS. 1, 2, and 3.

First, FIG. 3 shows an example of voltage waveforms at the input/output terminals of each block in FIG. 2. The waveform hole is a line-sequential color difference signal input from the input terminal 1o1, and two types of color difference signals (B-Y
, RY) are line-sequentialized alternately every 1H with different DC offsets. The waveform is a horizontal synchronizing signal input to the input terminal 103. Waveform C is a signal obtained by sample-holding waveform a by sample-and-hold circuit 20. Waveform d is a signal obtained by detecting the rising edge of waveform C by edge detection circuit 21.

Waveform e ld Positive output of D flip-flop 22 (Q
). Waveform f is the positive output (Q) of D-clip flop 23. The waveform g is the output of the mismatch counter 24, and a pulse is output when the mismatch between the waveform e and the waveform f continues for 4H. The waveform is a track jump pulse inputted from the input terminal 1o4, and the pulse is emitted when a track jump occurs.

As described above, according to this embodiment, the output of the υ color difference discrimination circuit is reversed by the track jump pulse when jumping to an adjacent track during high-speed reproduction, so that the waveform f in FIG.
As can be seen, the malfunction of the color difference discrimination circuit occurs only between ■ and ■. Therefore, the color inversion noise that occurs on the screen during high-speed reproduction is within one line Vi, and deterioration in image quality can be almost eliminated.

In view of the effects of the invention, the present invention provides a color difference discrimination circuit that generates a track jump pulse in synchronization with a jump to an adjacent track and maintains a constant output in synchronization with this track jump pulse. As a result, color inversion noise that occurs on the screen during track jumps during high-speed playback can be reduced to within one line, and deterioration in image quality can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a color signal reproduction processing circuit according to an embodiment of the present invention, FIG. 2 is a block diagram of a color difference discrimination circuit in FIG. 1, and FIG. 3 is an input/output terminal of each block in FIG. 2. Figure 4 is a block diagram of the conventional color signal reproduction processing circuit, Figure 6 is a block diagram of the color difference discrimination circuit in Figure 4, and Figure 6 shows the input and output of each block in Figure 5. Terminal voltage waveform diagram, Figure 7 shows normal playback and high-speed playback (the figure shows 3x speed)
FIG. 2 is a track locus diagram on an optical disk. 10...Color difference discrimination circuit, 12...Track jump pulse generation circuit, 20 Old...Sample bold circuit, 21...Edge detection circuit, 22.23...
- D flip-flop, 24...discrepancy counter. Name of agent: Patent attorney Toshio Nakao and 1 other person
,

Claims (1)

[Claims] Reproducing means for reproducing the line sequential color difference signal from an optical disk in which one frame of line sequential color difference signals obtained by converting two types of color difference signals into line sequential signals per horizontal scanning period is recorded on one track; a synchronizing means for alternately extracting and synchronizing color difference signals from the color difference signals every horizontal scanning period; and a track jump pulse generator for generating a pulse in synchronization with the jump of a reproduction beam from the optical disk to an adjacent track. a color difference discrimination circuit that discriminates the type of the reproduced color difference signal and controls the output of the synchronization means to be a predetermined color difference signal in synchronization with the output signal of the track jump pulse generation circuit based on the discrimination output; A color signal reproduction processing circuit comprising: