JPH10336603A - Digital television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital television receiver capable of utilizing the function of on-screen display even when it is in image recording without including unrequired video signals in signals for image recording. SOLUTION: Video data expanded in an MPEG decoder 16 are converted to YC composite signals by an NTSC encoder 18 and they are outputted as the signals for image recording. The YC composite signals from the NTSC encoder 18 and the YC composite signals outputted from the NTSC encoder 22 based on on-screen data from an OSD(on-screen data generator) chip 20 are superimposed by an analog switch 24 and outputted as the signals for a monitor. Thus, on-screen video signals are not included in the signals for image recording and the on-screen video signals are included only in the signals for the monitor. Thus, the unrequired video signals are not recorded in an image recorder and the on-screen function of the monitor is used at an optional timing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital television receiver, and more particularly, to a broadcast signal in which an information signal is multiplexed in addition to a video / audio signal such as a communication satellite (CS) digital television broadcast signal. The present invention relates to a digital television receiver for demodulating the broadcast signal and outputting a video signal to a monitor.

[0002]

2. Description of the Related Art In digital television broadcasting using a communication satellite, a video / audio data signal (MPEG signal) of a plurality of channels compressed by MPEG is multiplexed with an information data signal such as a program table and program detailed information. This multiplexed data signal is modulated by a predetermined modulation method such as QPSK or 16QAM and transmitted as a broadcast signal.

In the digital television receiver 1 shown in FIG. 5, the broadcast signal is received by the tuner unit 2 and demodulated into the original multiplexed data signal. The multiplexed data signal is supplied to a demultiplexer 3, which separates the multiplexed data signal into individual signals. The separated MPEG signal is decompressed by an MPEG decoder 4, demodulated into an analog television signal by an NTSC encoder 5, and output to a recording device (not shown) or a monitor (not shown).

[0004] When a program guide or detailed program information is displayed on the screen, the demultiplexer 3 extracts data corresponding to the program guide or detailed program information from the above-mentioned information signal and supplies the data to the CPU 6. Therefore, CP
U6 writes the given data to the preset fixed text for on-screen display in the memory 7, creates on-screen data (data for on-screen display), and displays a display instruction to the MPEG decoder 4. Is output. The MPEG decoder 4 reads the on-screen data from the memory 7 in response to the display command,
The on-screen data is multiplexed with the video data. Therefore, when the multiplexed data signal in which the on-screen data is multiplexed on the video data is demodulated into an analog television signal by the NTSC encoder 5, a video signal in which the on-screen display signal is multiplexed on the received video signal is obtained.

In the digital television receiver 1, when a desired channel is to be selected from a plurality of channels being transmitted, a desired channel number is directly input and a program table is displayed on the screen. There is a method in which the desired channel is displayed by moving the cursor on the display screen. When viewing a pay program called pay-per-view (PPV), a screen called a menu is displayed on-screen, and a purchase procedure can be performed in the menu screen.

[0006]

In the conventional digital television receiver 1 shown in FIG.
In order to superimpose on-screen data on video data, channel numbers, program guides, menus, and the like are always multiplexed on the video of the program currently being viewed for on-screen display. Therefore, when recording a program that is currently being viewed, even unnecessary video (on-screen video) is recorded. On the other hand, in order to remove such an on-screen video, it is necessary to prevent the on-screen data from being multiplexed in the MPEG decoder 4. In this case, however, the on-screen display cannot be performed during recording, and There has been a problem that it is not possible to make a reservation purchase of a PPV program by displaying a program guide and selecting a desired channel or displaying a menu screen.

[0007] Therefore, a main object of the present invention is to not include an unnecessary video signal in a recording signal and to use an on-screen display function even during recording.
It is to provide a digital television receiver.

[0008]

SUMMARY OF THE INVENTION The present invention is a digital television receiver for receiving a broadcast signal in which an information signal is multiplexed on a video signal, demodulating the broadcast signal and outputting the video signal to a monitor, A first circuit that outputs only a video signal as a recording signal, an on-screen signal output unit that outputs an on-screen signal based on an information signal, and a video signal and an on-screen signal that are multiplexed and output to a monitor as a monitor signal A digital television receiver including a second circuit.

[0009]

In digital television broadcasting using a communication satellite, for example, a signal in which an information signal is multiplexed in addition to a video / audio signal compressed according to the MPEG system is modulated by a modulation system such as QPSK or 16QAM and broadcast. Sent as a signal. A digital television receiver receives such a multiplexed broadcast signal,
A data signal is obtained by digital demodulation. Then, for example, the video data signal extracted by the demultiplexer is expanded by, for example, an MPEG decoder and applied to, for example, an NTSC encoder. Therefore, N
An analog television signal is output from the TSC encoder.

The first circuit outputs only the video signal output from the NTSC encoder as a recording signal. In the second circuit, for example, an on-screen data generator (O
SD) outputs an on-screen data signal, which is superimposed on the video signal in an analog or digital manner. Therefore, the second circuit uses the video signal on which the on-screen display video signal is superimposed as the monitor signal.
Output to monitor.

[0011]

According to the present invention, since the recording signal output from the first circuit does not include the on-screen display video signal, unnecessary video is not recorded. In addition, since the monitor receives the on-screen display video signal together with the video signal from the second circuit, the user can select a channel or make a program reservation using the on-screen display.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a digital television receiver 10 of this embodiment is for receiving a digital television broadcast by a communication satellite, for example.
A digital broadcast signal received by an antenna (not shown) is provided to the tuner unit 12. The tuner unit 12 selects broadcast data for 4 to 8 channels output from a desired transponder. The selected broadcast data is demodulated according to a data demodulation method such as QPSK or 16QAM, and becomes a transport stream composed of a plurality of transport packets. The tuner unit 12 is connected via a descrambler (not shown)
The transport stream is provided to the demultiplexer 14.

The demultiplexer 14 detects only a packet of a desired channel and supplies a video data signal of the packet to the MPEG decoder 16. MPEG decoder 1
6 decompresses the video data signal and outputs the NTSC encoder 18
Give to. Therefore, from the NTSC encoder 18,
A YC composite signal (analog television signal) is output. The YC composite signal from the NTSC encoder 18 is provided as a recording signal to a recording device (not shown). That is, the NTSC encoder 18 forms a part of the first circuit.

That is, the CPU 26 supplies a command signal for channel selection to the tuner unit 12, and also outputs the data compression ratio and the like of the selected channel to the demultiplexer 1.
4 and sets a compression rate (decompression rate) in the MPEG decoder 16. However, if the MPEG decoder 16 determines the compression rate (decompression rate) by itself,
No rate setting by the PU 26 is required. Also, CPU
26 executes a data error check, and according to the result, "Does the antenna come off?" Is displayed on the screen using the OSD chip 20 (described later). Then, since data of a plurality of channels is sent to the demultiplexer 14 at a time as described above, the CPU 26 instructs which video / audio data signal should be extracted. Also, the CPU 26
When converting a video data signal into an analog television signal by the NTSC encoder 18, the NTSC encoder 18 determines whether to add a copy protection signal (see Japanese Patent Publication No. 5-44235: Macrovision) or to add a closed caption. Instruct the encoder 18.

Also, PSI (program information) is assigned to a part of the above-mentioned transport packet. When a request is received from the CPU 26, the demultiplexer 14 outputs the program information, for example, the broadcast time of the program, the text of the program, and the like. Attribute data including a pointer to data and the like
Output to That is, the CPU 26 displays (a) when a power switch (not shown) is turned on, (b) when an update timing set in advance by a timer comes, or (c) when a user displays a program table or a menu. A request signal is supplied to the demultiplexer 14 when instructed.

On the other hand, in the memory 28, multiplexing timings and display formats or formats are stored in advance for on-screen display. Therefore, the CPU 26 reads out these data from the memory 28 in accordance with the given attribute data, and, together with the attribute data,
Give to. In this manner, the OSD chip (on-screen display data generator) 20 generates on-screen data based on the program information obtained by the CPU 26 from the demultiplexer 14.

The on-screen data from the OSD chip 20 is given to the NTSC encoder 22. Therefore, the NTSC encoder 22 outputs a YC composite signal of an on-screen video signal. In the prior art of FIG. 5, the function of the OSD chip 20 of the embodiment of FIG. 1 is achieved by the MPEG decoder 4 (FIG. 5), but in the embodiment of FIG.
The OSD chip 20 is used without using the SD superimposition function.

In the OSD chip 20, position information indicating which pixel of a monitor (not shown) should display an on-screen image can be obtained. Give a switching pulse. This analog switch 2
4 switches between a YC composite video signal obtained from a received signal from the NTSC encoder 18 and a YC composite signal obtained from on-screen data from the NTSC encoder 22 in accordance with the switching pulse, thereby forming two YC composite signals. Are superimposed. That is, the analog switch 24 selects the output of the NTSC encoder 22 at the pixel position on the monitor where the on-screen video is to be displayed, and selects the NTSC encoder at the other pixel positions.
A superimposed signal obtained by selecting the output of the SC encoder 18 is output as a monitor signal. That is,
The OSD chip 20, the NTSC encoder 22, and the analog switch 24 form a part of the second circuit.

According to the embodiment shown in FIG. 1, the YC composite signal output from the NTSC encoder 18 is output as a recording signal, and the YC composite signal on which the on-screen display signal output from the analog switch 24 is superimposed is used for monitoring. Output as a signal. Therefore, when recording is performed by the recording device using the recording signal, an unnecessary video signal (on-screen display signal) is not recorded. Also, even when recording is performed by the recording device, the monitor displays an image in accordance with the monitor signal output from the analog switch 24.
The video of the on-screen data created by the SD chip 20 is displayed. Therefore, even during recording, the user can confirm a program or make a program reservation using a program table or menu on the monitor screen.

In the embodiment shown in FIG. 1, the on-screen video signal and the received video signal are superimposed in an analog manner in the second circuit for generating the monitor signal. On the other hand, in the embodiment shown in FIG. Superimposed on In the embodiment of FIG. 2, the same or similar parts as those of the embodiment of FIG. In the digital television receiver 10 shown in FIG.
The expanded video data output from 6 is applied to the digital adder 30. The digital adder 30 is also supplied with on-screen data from the OSD chip 20. Therefore, the digital adder 30
Converts the received video data and on-screen data to OSD
The digital addition is performed according to the addition command from the chip 20, and the result is supplied to the NTSC encoder 22. As mentioned above,
Since the OSD chip 20 has position information indicating where the on-screen video is displayed on the monitor,
The SD chip 20 may give an addition command to the digital adder 30 at a necessary timing based on the position information. The output of the digital adder 30, that is, the data in which the on-screen data is superimposed on the received video data is demodulated by the NTSC encoder 22,
It becomes a composite signal. This NTSC encoder 22
Is output as a monitor signal, similarly to the output of the analog switch 24 in the embodiment of FIG.

In the embodiment shown in FIG. 2, the received video data and the on-screen data are digitally superimposed by the digital adder 30, so that they are superimposed in an analog manner using the analog switch 24 as in the embodiment shown in FIG. As compared with the case, switching noise such as undesired coloring of the leading edge or trailing edge of the on-screen image is reduced. In the embodiment shown in FIG. 2, the OSD chip 20 and the digital adder 30 may be integrated into one chip.

In the digital television receiver 10 shown in FIG. 3, an NTSC encoder 18 'different from the NTSC encoder 18 of the embodiment shown in FIG. 1 or 2 is used. The NTSC encoder 18 'can output a signal before color demodulation, that is, an RGB signal or a YUV signal. The RGB signal or the YUV signal from the NTSC encoder 18' is supplied to the analog switch 24. Also, the Y output from the NTSC encoder 18 '
The C composite signal is output as a recording signal, as in the embodiment of FIG. 1 or FIG.

In the embodiment shown in FIG.
The on-screen data output from
The digital / analog converter 32 outputs the RGB or YUV signal of the on-screen video. Accordingly, the analog switch 24 converts the RGB signal or the YUV signal from the digital / analog converter 32 and the RGB signal or the YUV signal from the NTSC encoder 18 'in accordance with the switching pulse from the OSD chip 20 as in the embodiment of FIG. Superimposed and output as a monitor signal. According to the embodiment of FIG. 3, since the video signal included in the monitor signal is not Y / C-demodulated, a high-resolution video signal can be given to the internal monitor.

As an IC which can be used as the NTSC encoder 18 of the embodiment shown in FIG. 1 or 2, there is, for example, "SAA7183A" manufactured by Philips, and an IC which can be used as the NTSC encoder 18 'of the embodiment shown in FIG.
"SAA7182A" manufactured by Philips
There is. Digital television receiver 10 shown in FIG.
Then, the decompressed video data output from the MPEG decoder 16 is supplied to the digital adder 30. The digital adder 30 is also supplied with on-screen data from the OSD chip 20. Therefore,
The digital adder 30 digitally adds the received video data and the on-screen data in accordance with an addition command from the OSD chip 20, and supplies the digitally added data to the NTSC encoder 22. The output of the digital adder 30, that is, the data in which the on-screen data is superimposed on the received video data is given to the digital / analog converter 32,
Therefore, from the digital / analog converter 32,
A YUV signal of the received video on which the on-screen video is superimposed is output. The YUV signal from the digital / analog converter 32 is output as a monitor signal.

In the embodiment of FIG. 4, in addition to the advantages obtained by the embodiments of FIGS. 2 and 3, since the monitor signal is output as a YUV signal, it is necessary to add a copy protect signal to the monitor signal. Since there is no monitor signal generation circuit, the restriction on the design of the second circuit is relaxed. Further, in any of the above-described embodiments, since the recording signal and the monitoring signal are separately generated or output, a warning message for preventing an inadvertent channel change during recording is displayed on-screen. be able to. In other words, the CPU 26 receives a signal indicating that recording is in progress from a recording device (not shown), and according to the recording in-progress signal, "cannot change channel because recording is in progress. By displaying the warning message on-screen as in [1], careless channel change during recording can be prevented. Also,
Since the CPU 26 knows the program reservation information set by the user, based on this information, "this program has been reserved. The on-screen display as described above can prompt the user to confirm whether or not to perform recording, and can prompt appropriate processing such as recording.

In order to display an on-screen image such as an arbitrary message at an arbitrary timing as described above, C
The PU 26 may supply the OSD chip 20 with the on-screen display command signal and the on-screen data each time.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram showing another embodiment of the present invention.

FIG. 3 is a block diagram showing still another embodiment of the present invention.

FIG. 4 is a block diagram showing another embodiment of the present invention.

FIG. 5 is a block diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Digital television receiver 16 ... MPEG decoder 18,18 ', 22 ... NTSC encoder 20 ... OSD chip 24 ... Analog switch 26 ... CPU 30 ... Digital adder 32 ... Digital / analog converter

Claims (4)

[Claims] 1. A digital television receiver for receiving a broadcast signal in which an information signal is multiplexed on a video signal, demodulating the broadcast signal, and outputting a video signal to a monitor, wherein the digital television receiver records only the video signal. A first circuit that outputs a signal, an on-screen signal output unit that outputs an on-screen signal based on the information signal, and a second circuit that multiplexes the video signal and the on-screen signal and outputs the multiplexed signal to the monitor as a monitor signal. A digital television receiver comprising two circuits. 2. The digital television receiver according to claim 1, wherein said second circuit includes analog superimposing means for superimposing said on-screen signal and said video signal in an analog manner. 3. The digital television receiver according to claim 1, wherein said second circuit includes digital superimposing means for digitally superimposing said on-screen signal and said video signal. 4. An encoder for demodulating a received video signal, wherein said encoder outputs a video signal before color demodulation, and said digital superimposing means outputs said video signal before color demodulation and said on-screen signal. 4. The digital television receiver according to claim 2, wherein