JPH1023345A - On-screen compositing circuit for digital broadcast receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an output of an on-screen composite image only at a TV monitor signal terminal without affecting a VTR output signal by compositing an analog luminance signal component of on-screen information with a luminance signal output to a TV monitor during video recording of the VTR. SOLUTION: When an on-screen display inhibit signal 1020 is active, since an AND element 1010 negates an on-screen selection signal(YS) by the on-screen display inhibit signal 1020, no YS 1030 is outputted to an on-screen compositing circuit 150. Since digital on-screen compositing is not conducted, a program signal not subject to on-screen compositing is outputted to Y, C signal outputs from a digital video encoder 16. On the other hand, a logic element 1011 provides an output of a YS signal from an on-screen generator 190 to an analog switch 2020 so as to throw the switch 2020 to the position shown in dotted lines. As a result, a luminance signal subject to on-screen compositing is outputted to a TV monitor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital broadcast receiver.

[0002]

2. Description of the Related Art Digital broadcasting and DSM (Digit) have been developed using digital compression coding technology of images developed in recent years.
al Storage Media), various devices using a digitally compressed image restoration apparatus have begun to be put into practical use.

[0003] In digital broadcasting, following the start of digital satellite broadcasting in the United States, in Europe and Asia including Japan,
Digital satellite broadcasting plans are in progress.

Conventionally, a digital broadcast receiver is generally configured as shown in FIG. FIG. 3 is a block diagram showing a configuration of a standard digital satellite broadcast receiver which is an example of a digital broadcast receiver.

In FIG. 3, reference numeral 100 denotes a tuner unit.
A desired physical channel is selected from intermediate frequencies from the LNB such as BS and CS.

[0006] 110 is a demodulation device, 120 is an error correction device, and reproduces a digital signal from a selected physical channel. A program extraction / separation device 130 extracts desired programs and program information from a plurality of multiplexed programs, and reproduces a system clock for decoding a compressed signal. Reference numeral 140 denotes a compressed image decompression device (hereinafter, referred to as a V decoder) which decompresses an encoded and compressed video signal.

Reference numeral 150 denotes an on-screen synthesizing device which multiplexes desired on-screen information on a video signal of a program.

Reference numeral 170 denotes a compressed audio signal decompression device (hereinafter, referred to as an A decoder) which decompresses an encoded and compressed audio signal. Reference numeral 160 denotes a video signal encoding device, which encodes a video signal into a baseband signal of a desired signal format, such as NTSC / PAL, and a television monitor 210, 21
5 VTR or the like. A microcomputer 180 controls the system of each unit. An on-screen information generator 190 outputs on-screen information such as an electronic program guide under the control of the microcomputer 180.

Reference numeral 200 denotes an IC card which performs encryption key decryption for descrambling a program, management of a viewing fee, and the like. With the above configuration, the program is displayed on the television monitor 2.
10 and reproduced on the VTR 215.

Further, an on-screen synthesizing section of a conventional digital broadcast receiver will be described with reference to FIGS. FIG. 4 is a block diagram showing a configuration of a main part of on-screen synthesis of a conventional digital broadcast receiver, and FIG. 5 is a signal waveform diagram for explaining the operation. In FIG. 4, FIG.
The same components as those described above are denoted by the same reference numerals, and description thereof is omitted here. 4 is a logical product device 1010 in FIG.
Reference numeral 0 denotes an on-screen display inhibition signal output from the microcomputer, which is normally enabled when VTR recording is set, thereby preventing erroneous multiplexing of on-screen information with a video signal being recorded.

Reference numeral 1030 denotes an on-screen information selection signal. The on-screen synthesizing device 150 multiplexes an on-screen signal to a program according to the selection signal. 165
Is a copy guard device built in the digital video encoding device 160, and prohibits recording of some programs on the VTR by inserting a protect signal into a vertical blanking period or a burst signal.

The operation of the on-screen composition unit configured as described above will be described with reference to FIG. First, the operation when the on-screen display inhibition signal 1020 is inactive, that is, during the on-screen display period will be described.
At this time, the program signals are sequentially output from the video decoder 140 as CBi, Yi, and CRi, as shown in FIG. On the other hand, the Ys output of the on-screen information generating device 190 becomes active from the position of CBi + 1 as shown in FIG.
On-screen information CB, Y, and CR are output. At this time, since the on-screen display inhibition signal 1020 is inactive, the AND device 1010 in FIG.
Ys of the on-screen information generator 190 as shown in FIG.
The output is output as is. As a result, the on-screen synthesizing device 150 performs on-screen synthesizing while the output of the logical AND device 1010 is active as shown in FIG. . As a result, the Y and C signals combined with the on-screen information are output from the digital video encoding device 160 as shown in the figure.

Next, the on-screen display inhibit signal 102
The operation when 0 is active, that is, in the on-screen display inhibition period, will be described. Also at this time, the Ys output of the on-screen information generating device 190 becomes active, but here, since the on-screen display inhibition signal is valid, the output of the AND device 1010 does not become active. Do not perform on-screen composition. As a result, the digital video encoding device 16
The Y and C outputs of 0 output a program video signal that is not subjected to on-screen synthesis.

This prevents erroneous on-screen synthesis from being performed during the on-screen display prohibition period such as during VTR recording.

[0015]

However, according to the above configuration, there is a problem that a program guide or the like cannot be confirmed on a monitor during an on-screen display prohibited period, for example, during VTR recording.

[0016]

In order to solve the above-mentioned problems, an on-screen synthesizing circuit for a digital broadcast receiver according to the present invention synthesizes an on-screen information with a restored digital video signal to produce an analog composite video signal or an analog Y video signal.
Encoding means for converting the luminance signal of the on-screen information into an analog signal when the on-screen information is not synthesized by a signal from the control means;
Switching means for switching the luminance signal output of the encoding means to the output signal of the conversion means when not synthesizing on-screen information and outputting the output signal to the display device,
According to the present invention, it is possible to output an on-screen screen such as a program guide on a monitor without outputting an on-screen composite screen for a program video signal for recording during VTR recording or the like.

[0017]

DETAILED DESCRIPTION OF THE INVENTION An on-screen synthesizing circuit for a digital broadcast receiver according to the present invention comprises an on-screen information generating apparatus for generating on-screen information in the form of luminance and color difference signals and an on-screen information selection signal, and a restored digital image. An on-screen combining device for multiplexing the on-screen information output from the control-screen information generating device with the on-screen information selection signal to a video signal, and an analog composite video signal output from the on-screen combining device Alternatively, a digital video encoding device that converts an analog Y / C signal to output to a storage device and a display device, a D / A converter that converts the digital luminance signal output of the on-screen information generating device to an analog signal, A microcomputer that outputs a display inhibit signal A first AND device for performing an AND operation of an on-screen information selection signal output from an on-screen information generation device and an on-screen display inhibition signal from the microcomputer; the on-screen display inhibition signal and the on-screen information selection signal And a second AND device that calculates the AND of the luminance signal output of the on-screen information from the D / A converter and the luminance signal output from the digital video encoding device. An analog switch that switches to a signal according to a signal and outputs the signal to the display device, and performs a conventional normal digital on-screen synthesis when a normal program is watched, such as during VTR non-recording.
During the on-screen display prohibition period such as during VTR recording, the luminance signal output of the on-screen information generating device is set to D / D.
By analog-combining the analog luminance signal component of the A-converted on-screen information with the luminance signal output to the TV monitor, the on-screen composition is not performed only for the TV monitor signal without performing the on-screen composition for the video signal output to the VTR. It has the effect of outputting a screen.

(Embodiment 1) An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a block diagram showing a configuration of a main part of an on-screen synthesizing circuit for a digital broadcast receiver in this embodiment. The same reference numerals are given to the same components as those of the conventional device shown in FIGS. 3 and 4 described above, and description thereof will be omitted.

In FIG. 1, reference numeral 1010 denotes a first AND device similar to the prior art, and reference numeral 1011 denotes a second AND device, which is a logical product of the on-screen display inhibition signal 1020 and the Ys output of the on-screen information generating device 190. Take. 2010
Converts a digital signal indicating a luminance signal component Y of the on-screen information generator into an analog signal by a D / A converter. An analog switch 2020 selects and outputs two analog signals, a luminance signal output Y of the digital video encoding device 160 and an on-screen luminance signal output Y of the D / A converter 2010, based on the output signal of the AND device 1011.

The operation of the on-screen synthesizing circuit for a digital broadcast receiver configured as described above will be described below with reference to FIG. FIG. 2 is a signal waveform diagram for explaining the operation of FIG.

First, the on-screen display inhibit signal 102
The operation at the time of normal program viewing where 0 is inactive, that is, on-screen display non-prohibition, will be described. Now, assuming that the Ys output of the on-screen information generator 190 is active from the position CBi + 2 of the output of the video decoder 140, that is, the on-screen synthesis is to be performed, as shown in FIG. Is inactive, Ys of the on-screen information generator 190 is output as it is, as in the conventional example. As a result, the on-screen combining device 150 performs digital on-screen combining, and the digital video encoding device 160 outputs an on-screen combined video signal.

On the other hand, at this time, the D / A converter 2010 converts the luminance signal Y of the on-screen information generation device 190 into an analog signal and outputs the analog signal. However, the on-screen display inhibition signal 1020 is inactive in the logical product device 1011. The Ys output of the on-screen information generator 190 is negated, and the analog switch 2020 is controlled to the solid line side in FIG. As a result, both the Y and C signals to the TV monitor 210
When the output of the digital video encoding device 160 is selected, an ordinary on-screen synthesized video signal is output.

Next, the on-screen display inhibit signal 102
Operation when 0 is active, that is, during VTR recording will be described. At this time, Y of the on-screen information generation device 190
s output is CBk of the video decoder 140 output as shown in the figure.
Assuming that active on-screen synthesis is performed from the position, the AND element 1010 outputs an on-screen selection signal Ys to the on-screen synthesis device 150 in order to negate the Ys signal by the on-screen display inhibition signal 1020. No digital on-screen synthesis is performed. As a result, as the Y and C signal outputs from the digital video encoding device 160, a program signal that is not subjected to on-screen synthesis is output.

On the other hand, at this time, the D / A converter 2010 converts the luminance signal Y of the on-screen information generator 190 into an analog signal as shown in FIG. In addition, at this time, the on-screen display inhibition signal 1
Since the switch 20 is active, the Ys signal of the on-screen information generator 190 is output to the analog switch 2020, and the analog switch 2020 is controlled to the dotted line in FIG. As a result, the analog switch 2020 outputs an on-screen synthesized luminance signal.

As a result of the above, even during the on-screen display prohibition period such as during VTR recording, it is possible to confirm a program table or the like by on-screen display on the TV monitor without affecting the video signal for VTR recording. Become.

[0027]

As described above, according to the present invention, at the time of normal program viewing, digital on-screen synthesis is performed and V
During the on-screen display prohibition period, such as during TR recording,
Since on-screen synthesis is performed in analog only to the TV monitor output signal using only the luminance signal component of the on-screen information, it is possible to check the program information and the like on the TV monitor without affecting the recorded video signal even for VTR recording. This can be done with a low-cost configuration.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a main part of an on-screen synthesis device for a digital broadcast receiver according to an embodiment of the present invention.

FIG. 2 is a signal waveform diagram for explaining the operation of the on-screen combining device for a digital broadcast receiver according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a conventional digital broadcast receiver.

FIG. 4 is a block diagram showing a configuration of a main part of a conventional on-screen synthesis device for a digital broadcast receiver.

FIG. 5 is a signal waveform diagram for explaining the operation of a conventional on-screen synthesis device for a digital broadcast receiver.

[Explanation of symbols]

 140 Video decoder 150 On-screen synthesis device 160 Digital video encoding device 180 Microcomputer 190 On-screen information generation device 1010 First logical product device 1011 Second logical product device 2010 D / A converter 2020 Analog switch

Claims (2)

[Claims] 1. An encoding means for synthesizing on-screen information with a restored digital video signal to convert it into an analog composite video signal or an analog Y / C signal and outputting it to a storage device and a display device; A converter for converting the luminance signal of the on-screen information into an analog signal when the on-screen information is not synthesized by a signal; and a luminance signal output of the encoding means for switching to an output signal of the converter when the on-screen information is not synthesized. An on-screen synthesizing circuit for a digital broadcast receiver, comprising: switching means for outputting to the display device. 2. An on-screen information generating device for generating on-screen information in the form of a luminance and color difference signal and an on-screen information selection signal;
An on-screen synthesizing device for multiplexing the on-screen information output from the on-screen information generating device by the on-screen information selection signal, and a digital signal output from the on-screen synthesizing device as an analog composite video signal or analog Y / A digital video encoding device for converting the digital luminance signal output from the on-screen information generating device into an analog signal; a digital video encoding device for converting the digital luminance signal output from the on-screen information generating device into an analog signal; A microcomputer to output, a first AND device that takes a logical product of an on-screen information selection signal output from the on-screen information generation device and an on-screen display inhibition signal from the microcomputer, and the on-screen display inhibition signal; The on-screen information selection signal A second logical device ANDing,
An analog signal that switches between a luminance signal output of on-screen information from the D / A converter and a luminance signal output from the digital video encoding device according to an output signal of the second AND device and outputs the luminance signal output to the display device An on-screen combining circuit for a digital broadcast receiver, comprising: a switch.