JPS61212986A - Comb-line filter circuit - Google Patents

Abstract

PURPOSE:To separate a brightness signal and a color signal by the small number of elements by mixing a reproduced brightness signal and a reproduced color signal in the state of being separated in bandwidth and passing them through a delay line for the share of 2 horizontal scanning periods of the charge transfer type. CONSTITUTION:The reproduced brightness signal of reproducing system of a color video tape recorder of the PAL system are passed through a low-pass filter 13 while the signals separated as to frequency are mixed together in a circuit 14 and supplied to a series circuit of delay lines 9, 10 of one horizontal period of the charge transfer type. The crosstalk components of the brightness signals are removed by the mixed signals from the circuit 14 and the output signals of the delay line while the brightness signals are removed by a low pass filter 11. The crosstalk components of the color signals are removed from the mixed signal and the output signal of the delay line 9 to separate the color signals.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a comb filter circuit suitable for use in separating luminance signals and color signals of recycled yarn of a PAL color video tape recorder.

[Summary of the invention]

The present invention is applied to a comb-shaped filter circuit used to separate luminance signals and chrominance signals in the reproduction system of a PAL color video tape recorder, for example, in which the reproduced luminance signals and the reproduced chrominance signals are separated in frequency bands. A mixed signal mixed in the state is supplied to a two-horizontal period delay line of the charge transfer type, and a luminance signal is obtained from the one horizontal period delay point of the two-horizontal period delay line of the charge transfer type. The crosstalk component between the 1-horizontal period delayed signal and the 2-horizontal luminance signal is removed, and this luminance signal is separated through a low-pass filter. 2 obtained at the output side of the delay line of
Crosstalk components between the horizontal period delay signal and the color signal are removed, and the color signal is separated using a bandpass filter, and a delay line of two horizontal periods is used, for example, in the playback system of a PAL color video tape recorder. This makes it possible to construct a comb-shaped filter circuit.

[Conventional technology]

Conventionally, for example, in a comb-shaped filter circuit used to separate the luminance signal and chrominance signal in the reproduction system of a PAL color video tape recorder, the crosstalk of the reproduced luminance signal is 2 fh (fh is the horizontal frequency) with respect to the main signal. A comb-shaped filter circuit as shown in FIG. 3 has been proposed as a comb-shaped filter circuit that interleaves the reproduced chromaticity signal, 0 stoke, and 7 fh interleave with respect to the main signal to separate the reproduced signal, luminance signal, and color signal +5-. ing. That is, in FIG. 3, (IY) indicates the reproduced luminance signal input terminal to which the reproduced luminance signal of the PAL system is supplied, and (IC) indicates the reproduced color signal input terminal to which the reproduced color signal of the PAL system is supplied. The reproduced luminance signal input terminal (IY) is connected to one input terminal of the subtraction circuit (2), and the reproduced luminance signal input terminal (IY) is connected to one input terminal of the subtraction circuit (2).
IY) is connected to one input terminal of a subtraction circuit (4) via a delay line (3) of one horizontal period rR from a charge transfer type CCD, for example, and this reproduced luminance signal input terminal (IY) is connected to the subtraction circuit. (4), and the output terminal of this subtraction circuit (4) is connected to the other input terminal of the subtraction circuit (2) via a limiter circuit (5).
A luminance signal output terminal (6Y) is derived from the output terminal of 2).

In this case, the reproduced luminance signal has a crosstalk component of 1 during recording.
Since it is interleaved in relation to the fh line offset frequency, crosstalk components can be removed by a comb filter circuit using a delay line (3) of one horizontal period.

In addition, the reproduced color signal input terminal (IC) is connected to one input terminal of the subtraction circuit (7), and the reproduced color signal input terminal (IC) is connected to a charge transfer type, for example, a delay line (8) of two horizontal periods of a CCD. The output terminal of this subtraction circuit (7) is connected to the other input terminal of this subtraction circuit (7) through the input terminal, and the color signal output terminal (6C) is derived from the output terminal of this subtraction circuit (7). Since it is interleaved at the 4 fh offset frequency, it is a comb filter circuit using a delay line (8) of 2 horizontal periods.

Stoke components can be removed.

[Problem that the invention seeks to solve]

The comb filter circuit used to separate the luminance signal and chrominance signal in the playback system of a conventional PAL color video tape recorder has a delay line (3) of one horizontal period and a delay line h (8) of two horizontal periods. ), and when this delay line is constructed of a charge transfer type, for example, COD, there is a disadvantage that the number of elements increases and the mounting space increases accordingly.

In view of this point, the present invention provides a comb-shaped filter circuit used to separate the luminance signal and chrominance signal in the reproduction system of a PAL color video tape recorder, for example, by constructing a comb-shaped filter circuit with a delay line for two horizontal periods. The purpose is to

[Means for solving problems]

In the present invention, as shown in FIG. 1, the crosstalk of the reproduced luminance signal is interleaved with the main signal by 2 fh (fh is the horizontal frequency), and the crosstalk of the reproduced color signal is interleaved with the main signal by 7 fh. In the comb-shaped filter circuit that separates the luminance signal and color signal, a mixed signal obtained by mixing the reproduced luminance signal and reproduced chrominance signal in a state where they are separated in frequency bands is passed through a charge transfer type delay line of two horizontal periods. (9) α0, and the luminance signal is the mixed signal and this charge transfer type delay line of two horizontal periods (9) α
Crosstalk components between the one horizontal period delayed signal and the brightness signal taken from the one horizontal period delay point (9) indicated by the mark are removed, and the brightness signal is separated through a low pass filter (11). The chrominance signal is combined with this mixed signal and the 2-horizontal period delayed signal obtained at the output side of the charge-transfer type 2-horizontal period delay line (9) α1, which removes crosstalk components of the chrominance signal and passes through a band-pass filter. 02 to separate color signals.

[Effect]

According to the present invention, since a charge transfer type delay line of two horizontal periods can be used to separate both the luminance signal and the color signal, this comb filter circuit can be used as a charge transfer type delay line of two horizontal periods. Yang Cheng can do it.

〔Example〕

The one tip side of the comb-shaped filter circuit according to the present invention will be explained below with reference to FIG. In FIG. 1, parts corresponding to those in FIG. 3 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

The playback brightness signal of the Kiryu system of the PAL color video tape recorder, which is supplied to the playback brightness signal input terminal (IY), is sent to the adder circuit α via a low-pass filter 〇; 9 that passes only the playback brightness signal, for example, 4 MHz or less. The reproduction color signal of the reproduction system of a PAL color video tape recorder is supplied to one input terminal of ◆, and is also supplied to the reproduction color signal input terminal (IC).For example, only the reproduction color signal is 4.43MH.
It is supplied to the other input terminal of the adder circuit 04 via a band pass filter 09 that passes the signal of z. This adder circuit ◇◆ mixes the reproduced luminance signal and reproduced color signal separated in frequency bands. This mixed signal obtained at the output side of the adder circuit 041 is transmitted through two delay lines (9) and 0 (0) of one horizontal period each configured in a charge transfer type, for example, COD.
The delay line (9) is supplied to the input side of the delay line (9) of the series circuit. Further, the mixed signal of the reproduced luminance signal and the Tono color signal obtained at the output side of the adder circuit 0 is supplied to the input terminal of the adder circuit α1j via an attenuator 00 which sets the signal level to -.
The output signal of the delay line (9) from which a signal delayed by one horizontal period is obtained is supplied to the input terminal of this adder circuit, and the signal delayed by two horizontal periods is supplied to the output side of the delay line OQ. The signal level is supplied to the input terminal of the adder circuit 07+ via the attenuator side that makes the signal level negative, and only the frequency of the attenuator plane and the luminance signal to be applied is 4, for example.
It is connected to the luminance signal output terminal (6Y) via a series circuit of MI (low-pass filter 01 that passes below z).

In this case, the mixed signal of the reproduced luminance signal and the reproduced color signal, this one horizontal period delayed signal, and this two horizontal period delayed signal are added by the adder aη in a predetermined level relationship. The transfer function H@) of the reproduced luminance signal at this time is H(Z) = 7 (1 + Z ) = -L- (z + 1 + 2 + z-'). The characteristics when passing through are strange, and the delay time is equal to z-1. Therefore, the output signal of the adder circuit (1711) has the crosstalk component of the reproduced luminance signal removed as in FIG. 3, but contains the reproduced color signal and its crosstalk component. Low-pass filter (11) that passes only the frequency signal of the luminance signal
By passing it through, only the luminance signal can be separated.

In addition, a mixed signal of the reproduced luminance signal and the reproduced color signal obtained at the output side of addition circuit no. A signal is supplied to the other input terminal of this subtraction circuit axis, and the output terminal of this subtraction circuit axis is supplied with an attenuator CD to set the signal level to 100. It is connected to the color signal output terminal (6C) through the pass filter (2).In this case, the reproduced color signal is a mixed signal of the reproduced luminance signal and the reproduced color signal, and the delayed signal of these two horizontal periods or the subtraction circuit ψ. The crosstalk component of this color signal is removed as in the conventional method.The transfer function H(Z) at this time is H(Z) =7(1-Z) ==-T(z+1z- 1), and the delay time becomes z-1.The output signal of this subtraction circuit axis is not a chrominance signal, but also contains high-frequency components of the reproduced luminance signal, so this output signal is calculated only by the frequency of the chrominance signal. By passing the p-color signal through a band-pass filter a2, only the color signal can be separated and obtained at the p-color signal output terminal (6C).

As described above, according to this example, the reproduced luminance signal and the reproduced chrominance signal are limited to their respective bands and mixed before being passed through the delay line. It is possible to obtain a comb filter circuit that can separate both color signals.

Therefore, when this delay line is constructed using a charge transfer type, for example, a COD, it is advantageous in terms of fewer elements, lower cost, and less mounting space.

Furthermore, in the above example, the delay times of the luminance signal and the color signal can be made to match, and the luminance signal system also has two horizontal period delay lines (
9) Since it is a comb-shaped filter circuit using αO, it is possible to improve the performance of color video signals.

FIG. 2 shows another embodiment of the present invention, and this FIG. 2 shows an example in which the comb-shaped filter circuit for the luminance signal system of the example in FIG. 1 is made into a dynamic type. To explain this Fig. 2, the first
Portions corresponding to those in the figures are given the same reference numerals, and detailed explanation thereof will be omitted.

In the example in Figure 2, 1 is obtained at the output side of the delay line (9).
The horizontal period delay signal is supplied to the input terminal of the subtraction circuit (22) and the addition circuit 04! The mixed signal obtained at the output side of 1 is supplied to the negative terminal of this subtraction circuit, 2 (221) via attenuator αO, and the delay circuit M (1 (
The two-horizontal period delayed signal obtained on the cutting edge side of υ is supplied to the negative terminal of a subtraction circuit (221) via a fattenuator α, and the output signal of this subtraction circuit (22) is converted to the frequency of the luminance signal by one attenuator '15Jls, for example, 4MHzv. One horizontal period is supplied to one of the input terminals of the subtractor circuit (2) through a low-pass filter (23) that passes below and a limiter circuit C241 that performs amplitude limitation and is obtained at the output side of the delay line (9). The delayed signal is set to the frequency of the luminance signal, for example 4
The signal is supplied to the other input terminal of the subtraction circuit 05) through a low-pass filter (A) that passes frequencies below MHz, and the output terminal of this subtraction circuit (2-gloss) is connected to the luminance signal output terminal (6Y).Others is constructed in the same manner as in FIG.

In Fig. 2, the subtractor circuit outputs the mixed value of the reproduced luminance signal and the reproduced chrominance signal, the one horizontal period delayed signal, and the two horizontal period delayed signals to output a luminance signal cross to this output terminal. The signal of the crosstalk component of the ten color signals of the ten color signals is obtained, and the belief is that the low pass filter (23
), and only the crosstalk component of the luminance signal train is obtained at the output side of this ibar pass filter (23),
The crosstalk component of this luminance signal is transmitted to the limiter circuit f24.
) is supplied to the subtraction circuit (29), and at the output side of the low-pass filter (26), a reproduced luminance signal delayed by one horizontal interval, that is, a signal of the crosstalk component of the luminance signal is sent. Since this is supplied to the subtraction circuit (25), only the luminance signal can be obtained at this output terminal, that is, the !41 output terminal (6Y).The crosstalk component of this combined luminance signal is sent to the limiter circuit. Since the amplitude is limited in (24), it is possible to obtain a characteristic that changes the pass amplitude and range of the comb filter circuit of this luminance signal system according to the amplitude of the reproduced luminance signal (according to the vertical correlation). The signal system is the same as in Figure 1.

It is easy to understand that the example shown in FIG. 2 also provides the same effects as the example shown in FIG.

Note that the present invention is not limited to the above-described embodiments, and other configurations may be adopted without departing from the gist of the present invention. Of course.

〔Effect of the invention〕

According to the present invention, the reproduced luminance signal and the reproduced color (iI4) are mixed in a band-separated state, and this mixed signal is applied to the delay line 1B, so that the charge transfer type 2
It is possible to obtain a comb-shaped filter circuit that can separate both a luminance signal and a chrominance signal using a delay line for a horizontal period, and has advantages such as a correspondingly smaller number of elements, lower cost, and smaller mounting space.

[Brief explanation of drawings]

Figure 1 is a block diagram showing one embodiment of the comb filter circuit of the present invention, Figure 2 is a block diagram showing another embodiment of the present invention, and Figure 3 is a block diagram showing another embodiment of the comb filter circuit of the present invention.
The figure is a configuration diagram showing an example of a conventional comb filter circuit. (IY) is reproduction luminance No. 46 input terminal, (IC) is reproduction color signal input terminal, (6Y) is luminance signal output terminal, (6C)
are color signal output terminals, (91 and 00) are each one horizontal period delay spinner consisting of CCD, (111 and α) are low pass filters, respectively, 07/ and 0υ are band pass filters, respectively, a41 and αno are an addition circuit, and 翰) is a subtraction circuit, respectively. -cncm

Claims (1)

[Claims] The crosstalk of the reproduced luminance signal is 1/2f_ with respect to the main signal.
h (f_h is the horizontal frequency), and the crosstalk of the reproduced color signal is 1/4f_h interleaved with respect to the main signal to separate the luminance signal and the color signal. A mixed signal obtained by mixing the signal and the reproduced color signal in a state where they are separated in frequency bands is supplied to a charge transfer type delay line of two horizontal periods, and a luminance signal is a mixture signal obtained by mixing the above mixed signal and the above two charge transfer type delay lines. Crosstalk components between the one horizontal period delayed signal extracted from one horizontal period delay point of the horizontal period delay line and the luminance signal are removed, and the luminance signal is separated through a low pass filter, and the color signal is the above mixed signal. and a two-horizontal period delayed signal obtained on the output side of the two-horizontal period delay line of the charge transfer type, and the crosstalk component of the color signal is removed and the color signal is separated through a band-pass filter. A comb-shaped filter circuit.