JPH01162496A - Color signal processing device - Google Patents

Abstract

PURPOSE:To completely erase a pilot burst signal at the time of a reproduction by using a second pulse formed from a horizontal synchronizing pulse with a pulse width wider than a first pulse formed from the horizontal synchronizing pulse used at the time of a recording. CONSTITUTION:A timing to erase a pilot burst signal is executed by the second pulse generated by the second pulse generator 19. The second pulse is formed as the pulse with a wider pulse than the first pulse based on an H pulse generated by an H pulse generation circuit 7. Consequently, the extension of the pilot burst signal at the time of a reproducing is completely erased.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a color signal processing device that is effective for use in PAL color V'l''R and the like.

(Prior art) For example, in consumer color VTRs, etc., generally,
The luminance signal is subjected to FM modulation, the color signal is subjected to frequency conversion processing, and the opposite demodulation or frequency conversion operation is performed for recording or reproduction.

FIG. 2 is a block diagram showing color signal processing during recording and playback of a conventional PAL VTR. For example, a VTR composite video signal input from an input terminal 1 is applied to a BPF (band pass filter) 2. Only the chrominance signal is taken out by low-frequency conversion, and is added to an ACC (automatic gain control circuit) 3 for amplitude control, and is used as an input chrominance signal to one terminal a of the switch circuit 4. A signal having the same frequency as the color burst (hereinafter simply referred to as burst) signal frequency, that is, the subcarrier frequency, is input from the input terminal 5 to the other terminal.

On the other hand, a horizontal synchronizing signal is applied from the input terminal 6, and a horizontal synchronizing pulse (hereinafter abbreviated as H pulse) generator 7 generates an H pulse signal synchronized with the horizontal synchronizing signal. A first pulse is generated by a pulse generator 8 of.

The switch circuit 4 is connected to the first pulse generator 8, which is a part of the timing period of the horizontal synchronizing signal outputted from the first pulse generator 8.
- during the period of the pulse, select the signal of the subcarrier frequency from the input terminal 5 as the pilot verse 1 ~ signal,
Insert into the color signal applied to terminal a.

In the switch circuit 4, the color signal into which the pilot verse 1 to signals have been inserted is low frequency converted by a frequency converter 9, unnecessary components are removed by a low pass filter (L I) F (low pass filter) 10, and the color signal is output from an output terminal 11. The FM-modulated luminance signal is superimposed on the FM-modulated luminance signal and recorded.

In the case of reproduction, a reproduction signal is applied from the input terminal 12,
Ll) The color signal is extracted by low frequency conversion by F1a,
The ACCI 4 limits the amplitude and the frequency converter 15 creates a carrier color signal. At this time, the pilot burst signal is used to correct fluctuations in the time axis during reproduction.

The BPF 16 removes unnecessary components from the color signal created above, and the switch circuit 17 outputs the color signal to the pylon 1 according to the first pulse output from the first pulse generator 8.
The HEVERS 1- signal is canceled and output to output terminal 18 to be mixed with the luminance signal.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional color signal processing device, the output of the first pulse generator, which is the same as the timing for inserting the pilot burst signal used in recording, is used.
Since the pilot verse 1~ signal is deleted from the color signal during playback, LPF and BP used during recording and playback.
Due to the difference in the characteristics of F, there was a problem in that a part of the signal from Pikotsu 1 to Perth 1 with an extended width remained without being erased during reproduction.

The present invention aims to eliminate the above problems.

(Means for Solving the Problems) The present invention has achieved the above object by recording a video signal by inserting a pilot burst I signal of a subcarrier frequency into a color signal in a horizontal synchronization signal period, and when reproducing the video signal, the pylon 1
~Perspective 1- Created from horizontal synchronizing pulses used to determine the timing to insert pilot burst signals during recording in color signal processing circuits such as VTRs that use signals to correct time axis fluctuations in reproduction. This is achieved by erasing the pilot burst signal during reproduction using a second pulse having a wider pulse width than the first pulse (operation). A pulse indicating when to erase the
Since a second pulse different from the first pulse, which is wider than the width of the first pulse used for the timing of inserting the pilot burst signal during recording, is used, the pilot burst signal during playback is lengthened due to the characteristic difference between LPF and BPF. will also be completely deleted.

(Example) Hereinafter, the present invention will be explained in detail by way of an example using the drawings.

FIG. 1 shows a block diagram showing a color signal processing device according to an embodiment of the present invention, 19 is a second pulse generator, and the other configurations are the same as the conventional example shown in FIG. 2 to avoid duplication. Therefore, detailed explanation will be omitted.

The present invention allows the timing of erasing the pylon 1-burst signal to occur from the second pulse generated by the second pulse generator 19.

The second pulse is created based on the H pulse generated by the H pulse generation circuit 7 as a pulse having a width wider than the first pulse.

In the present invention configured as described above, in the case of reproduction, the pilot burst signal is erased by the second pulse having a wider period than the first pulse used in the case of recording. This means that the elongation of the Pikotsu 1 to Perth 1 signals during playback, which occurs due to the use of different BPF and LPF, is completely eliminated.

(Effects of the Invention) As is clear from the above explanation, the configuration of the present invention is such that the pilot verse 1 signal, whose width has been extended due to the characteristics of the LPF and BPF during reproduction, is converted into a pilot verse 1 signal whose width is wider than that at the time of insertion. Since the burst signal is erased by the timing of the pulse No. 2, the burst signal to the pylon 1 is completely erased, and there is an effect that it does not adversely affect the reproduced signal.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a color signal processing circuit according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional color signal processing device. 3.14...ACC (automatic gain control circuit), 7...
Horizontal synchronization pulse generator, 8... first pulse generator,
9, 15... Frequency converter, 19... Second pulse generator. Patent applicant Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] Color signal processing for VTRs, etc. that records a video signal by inserting a pilot burst signal of a subcarrier frequency into the color signal of the horizontal synchronization signal period, and uses the pilot burst signal during playback to correct the time axis fluctuation of playback. In the circuit, a second pulse generated from the horizontal sync pulse is used, which has a wider pulse width than the first pulse generated from the horizontal sync pulse, which is used to determine the timing of inserting the pilot burst signal during recording. A color signal processing device characterized in that the color signal processing device is configured to erase a pilot burst signal during reproduction.