JP2523738B2 - Television receiver - Google Patents

Description

TECHNICAL FIELD The present invention relates to an IDTV (Improved Televisio) which improves image quality of television by performing image processing using a large-capacity memory.
n) is related to television receivers.

2. Description of the Related Art In recent years, IDTV receivers have been attracting attention as next-generation high-definition television receivers. However, television receivers have been positioned as household information terminals rather than simply receiving broadcast radio waves.
It corresponds to various signals, such as a signal in which a C (color) signal temporally changes with respect to a Y (luminance) signal, or a signal from the S terminal that is YC separated and input. There is a need and measures are urgently needed. (Nikkei Electronics,
1987-10-19, No. 432 P.P. 102-105).

Hereinafter, an example of the above-mentioned conventional IDTV receiver will be described with reference to the drawings.

In FIG. 2, reference numeral 1 denotes an input terminal for a composite video signal, 2
Is an output terminal for a double-speed converted Y signal, 3 is an output terminal for a double-speed converted I signal, 4 is an output terminal for a double-speed converted Q signal, and 5 is an analog-digital converter (hereinafter referred to as an A / D converter). Abbreviated), 6 is a line memory, 7 is a frame memory, 8,
9 is a subtractor, 10 is a 2-input 1-output switch, 11 is a bandpass filter, and 12 is a subtractor. A color demodulation circuit 13 outputs two color difference signals of an I signal and a Q signal from the input composite video signal. 14 is an A / D converter for I signal, 15 is Q
An A / D converter for signals, and 16 is a synthesizing circuit for converting parallel data of the I signal and the Q signal output from the A / D converters 14 and 15 into an IQ signal of serial data. 17 is a line memory, 18 is a frame memory, 19 is an adder, 20 is a subtractor,
Reference numeral 21 is an adder, 22 is a switch with two inputs and one output, and 23 is a motion detection circuit. A scanning line interpolation circuit 24 converts the input Y signal and IQ signal from an interlaced signal to a double density signal. 25 is a digital-analog converter for the Y signal (hereinafter
It is abbreviated as D / A converter). Reference numeral 26 denotes a separating circuit which is an inverse operation of the synthesizing circuit 16 and produces an I signal and a Q signal from the IQ signal.
Reference numeral 27 is a D / A converter circuit for I signals, and 28 is a D / A converter circuit for Q signals. 29 is a horizontal sync separation circuit that inputs the composite video signal and separates and outputs the horizontal sync signal, and 30 is the output of the frequency divider circuit 33
The input of the output of and the output of the horizontal synchronization separation circuit 29, the phase difference is detected, the phase comparator that performs the output according to the phase difference,
Reference numeral 31 is a low pass filter for integrating the error voltage output of the phase comparator 30, 32 is a voltage controlled oscillator, 33 is a frequency divider circuit, 34 is a clock output terminal, and 35 is a horizontal synchronizing pulse output terminal.

Regarding the conventional IDTV receiver configured as described above,
The operation will be described below.

First, the clock generation circuit that obtains a clock at the clock output terminal 34 is configured by a so-called line lock PLL locked in horizontal synchronization. For example, if the frequency division ratio of the frequency dividing circuit 33 is 910, the output of the horizontal period separating circuit 29 is the frequency dividing circuit 3
Since the phase comparator 30 controls the voltage-controlled oscillator 32 through the low-pass filter 31 so that it has the same phase as the output of 3,
The output of the clock output terminal 34 becomes a signal having a frequency obtained by multiplying the output of the horizontal sync separation circuit 29 by 910.

When the system is driven using such a clock, for example, the difference between the input and output of the line memory 6 is subtracted by the subtracter 8
Even in the case of calculation, the processing becomes easy because there is always a fixed number of data in one horizontal synchronization.

However, on the other hand, in the color demodulation processing, the clock locked to the burst signal is easier to handle. Therefore, color demodulation is first performed by the analog color demodulation circuit 13, and the baseband IQ output is A / D converted by the line lock clock by the A / D converter 14 and the A / D converter 15. . In the Y signal system, the input of the composite video signal input terminal 1 is directly analog-digital converted by the A / D converter 5. The subtracter 8 takes the difference between the input and output of the line memory 6, and the subtracter 9 takes the difference between the input and output of the frame memory 7. The switch 10 is controlled by the output of the motion detection circuit 23, and for each pixel, the subtracter 8 in the case of a moving image.
, And in the case of a still image, the output is switched to the subtractor 9. A color component is extracted from the output of the switch 10 through a bandpass filter 11, and a subtracter 12 obtains a Y signal by subtracting the difference from the composite video signal. For color signal system, line memory 17
The sum of the input and output of is taken by the adder 19, and the sum of the input and output of the frame memory 18 is taken by the adder 21, and again, the output of the motion detection circuit 23 is used to switch the switch 22, and the cross color Obtain the removed IQ signal. The inputs of the motion detection circuit 23 are the output of the subtracter 9 which is the frame difference of the Y signal system and the output of the subtracter 20 which is the frame difference of the color signal system. The former low-frequency component detects the motion of the Y low-frequency component, and the latter detects the color and the motion of the Y high-frequency component.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the configuration as described above, the deviation of the detection time between the motion component from the Y signal system and the motion component from the color signal system is an analog deviation of the color demodulation circuit 13. Therefore, there is a problem that the motion detection is incomplete and the motion detection becomes incomplete.

In view of the above problems, the present invention provides motion detection with a Y signal,
An object of the present invention is to provide an IDTV receiver by line lock, which has no time error with motion detection in color signals.

Means for Solving the Problems In order to solve the above problems, a television receiver of the present invention has a composite video signal input terminal, a carrier color signal input terminal, and a composite video signal input signal input terminal. A data delay circuit connected to the terminal with variable delay setting, a luminance signal separation circuit connected to the output of the data delay circuit, and a color demodulation circuit outputting a color difference signal connected to the input terminal of the carrier color signal A cross color removal circuit connected to the output of the color demodulation circuit, a scanning line interpolation circuit connected to the outputs of the luminance signal separation circuit and the cross color removal circuit, and an input terminal of the composite video signal. It is provided with a horizontal sync separation circuit and a clock generation circuit for multiplying the horizontal sync separation output signal to generate a clock.

Action Due to the above, the characteristics of the signal source such as broadcast radio wave, S-VHS
Even if an error occurs in the signal delay between the luminance signal system and the color signal system by switching the characteristics of the color demodulation circuit according to each signal input such as input, EDTV broadcast, etc., it is inserted into the luminance signal system by the microcomputer. By adjusting the delay amount of the data delay circuit, the error is corrected and the motion detection with higher accuracy is performed.

Example Hereinafter, an IDTV receiver according to an example of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the structure of an IDTV receiver according to an embodiment of the present invention. In FIG. 1, 1 to 35 are the same as those in FIG. The description is omitted.

36 is an input terminal for the carrier color signal, 37 is a data delay circuit, 38
Is a delay amount setting terminal for inputting a control signal for controlling the delay amount of the data delay circuit 37 from the microcomputer 40, 39 is a characteristic switching terminal of the color demodulation circuit 13, 40 is a microcomputer, 41 is a remote control circuit, and 42 is Composite video signal input terminal, 43 is YC separation signal input terminal, 44 is a tuner section that receives broadcast radio waves and outputs a composite video signal, 45 is a microcomputer input from these 42 to 44 signal inputs according to instructions from the remote controller 41 This is a signal changeover switch for outputting a desired signal to the composite video signal input terminal 1 and the carrier color signal input terminal 36 under the control of 40.

The operation of the IDTV receiver configured as above will be described below.

First, the characteristics of the color demodulation circuit 13 will be described with reference to FIG. Fig. 3 shows the frequency characteristics of the band amplifier of the color demodulation circuit, where a is the frequency of the color subcarrier of 3.58MHz.
This is an example of so-called narrow-band demodulation that uses only the ± 0.5 MHz component centered on. b is an example of so-called wideband demodulation in which the bandwidth is expanded to ± 1 MHz or more. NTSC system color signal is 1.
I signal with 5MHz bandwidth and Q with 0.5MHz bandwidth
The narrow band demodulation as shown in FIG. 3a causes loss of the fine color portion. Nevertheless, most conventional television receivers have used narrow band demodulation because the circuit is simple and the interference (cross color) of the Y signal with the color signal can be reduced. . However, in the IDTV receiver, since cross color can be reduced by digital signal processing, wide band demodulation as shown in FIG. 3b is adopted from the viewpoint of image quality improvement. However, considering other factors such as noise, it is not a good idea to perform wideband demodulation on all input signals.
For the signal from the tuner section 44, narrow band demodulation should be performed, and if high quality signals from package media such as the composite video signal input terminal 42 and the YC separation signal input terminal can be expected, wide band demodulation should be performed. Then, the characteristics of the color demodulation circuit 13 are switched through the characteristics switching terminal 39 by the microcomputer 40 in correspondence with the control of the signal changeover switch 45.

However, a problem at the time of switching is a difference in group delay of color signals. The group delay of narrow band demodulation is larger than that of wide band demodulation. In order to absorb the difference, the delay amount setting terminal 38 by the microcomputer 40 is set so that the delay amount of the data delay circuit 37 inserted in the data line of the Y signal is larger in the narrow band demodulation than in the wide band demodulation. Control through. This delay circuit 37 can be easily realized by a shift register and a switch.

With such a configuration, the deviation between the Y signal and the color signal can be prevented, which is important for the accurate operation of the motion detection circuit 23.

As described in the conventional example, the motion detection circuit 23 of this configuration is
The subtractor 20 detects the movement of the high frequency component of the Y signal (the portion where the signal differs between frames is called movement). That is, the frame difference of the interference component (cross color) of the high frequency component of the Y signal to the color signal is detected, and when it is determined that it is moving, the switch 10 of the Y signal system is determined to the subtractor 8 and it is determined to be stationary. If so, they are connected to the subtractor 9, respectively.

As described above, regarding the signal of the high frequency component of Y, since the signal system and the detection source (color signal) are different, if there is a deviation between the Y signal and the color signal, it causes a serious problem in image quality. An example configuration is required.

In the present embodiment, the characteristics of the color demodulation circuit 13 are switched by the microcomputer 40 in conjunction with the signal changeover switch 45. However, for example, color subcarrier, horizontal,
Color demodulation circuit 1 is used as wideband demodulation when each vertical frequency matches the NTSC system and the S / N ratio in the vertical blanking period is good.
3. A method of automatically controlling the delay circuit 37 may be used.

As described above, according to the present invention, a composite video signal input terminal, a carrier color signal input terminal, and a data delay circuit connected to the composite video signal input terminal and having a variable delay setting, A luminance signal separation circuit connected to the output of the data delay circuit, a color demodulation circuit connected to the input terminal of the carrier color signal to output a color difference signal, and a cross color removal circuit connected to the output of the color demodulation circuit, The scanning line interpolation circuit connected to the outputs of the luminance signal separation circuit and the cross color removal circuit, the horizontal synchronization separation circuit connected to the input terminal of the composite video signal, and the horizontal synchronization separation output signal are multiplied. By providing a clock generation circuit that generates a clock,
It is possible to realize an IDTV receiver using a line-locked clock, which has no time difference between motion detection using a luminance signal and motion detection using a color signal.

[Brief description of drawings]

FIG. 1 is a block diagram of a television receiver in an embodiment of the present invention, FIG. 2 is a block diagram of an example of a conventional television receiver, and FIG. 3 is a characteristic diagram for explaining the operation thereof. Is. 1 ... Composite video signal input terminal, 5 ... A / D converter, 13
…… Color demodulation circuit, 14 …… A / D converter, 15 …… A / D converter,
24 ... Scan line interpolation circuit, 29 ... Horizontal sync separation circuit, 34 ...
… Clock output terminal, 36… Carrier color signal input terminal, 37…
... data delay circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Ishizu 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Kenta Samukawa, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Ryuji Matsuura 1006, Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. (56) References: 60-186775 (JP, U) Nikkei Electronics, [432] (1987-10- 19) P. 102−105

Claims (2)

(57) [Claims] 1. A composite video signal input terminal, a carrier color signal input terminal, a data delay circuit having a variable delay setting for delaying the composite video signal, and an output of the data delay circuit. A luminance signal separation circuit, a color demodulation circuit for outputting a color difference signal connected to the input terminal of the carrier color signal, a cross color removal circuit connected to the output of the color demodulation circuit, the luminance signal separation circuit and a cross A scanning line interpolation circuit connected to the output of the color removal circuit, a horizontal sync separation circuit connected to the terminal of the composite video signal, and a clock for multiplying the horizontal sync separation output signal output from the horizontal sync separation circuit. A clock generation circuit for generating
A motion detection circuit that controls the luminance signal separation circuit, the cross color removal circuit, and the scanning line interpolation circuit by inputting the frame difference of the output signal of the data delay circuit and the frame difference of the output signal of the color demodulation circuit. A television receiver comprising: a demodulation characteristic of the color demodulation circuit and a delay amount of the data delay circuit, which are switched according to an input signal of a composite video signal / carrier color signal. 2. A demodulation characteristic of a color demodulation circuit and a delay amount of a data delay circuit are switched in synchronism with switching of input signals of a composite video signal and a carrier color signal. The television receiver set forth in claim 1.