JP2835229B2 - Video / audio independent switching circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to independently determine whether or not a signal transmitted in pay satellite broadcasting or the like is scrambled, for video and audio independently, and to automatically switch whether or not to pass through a decoder. The present invention relates to an independent video / audio switching circuit.

[0002]

2. Description of the Related Art Conventionally, a scrambled broadcast, such as a pay broadcast, is received by an electronic device such as a television with a built-in BS or a BS tuner, and it is automatically determined whether or not the broadcast is a scrambled broadcast. Various methods have been devised for switching whether or not to pass through the decoder. FIG.
FIG. 3 is a block diagram showing a configuration of a BS tuner unit of a conventional television with a built-in BS.

In this figure, 1 is a BS tuner, 2 is a video demodulation circuit, 3 is a QPSK demodulation circuit, 4 is a PCM demodulation circuit, 5 is a D / A converter, 6 is a microcomputer, and 7 is an interlocking switch. The PCM demodulation circuit 4 has a video scramble determination function.

When a channel selection command is given to the microcomputer 6 as an external command signal, the microcomputer 6 controls the tuner 1 to receive satellite broadcasting. The output of the tuner 1 becomes an FM demodulation signal, which is input to the video demodulation circuit 2 and also to the QPSK demodulation circuit 3 at the same time. One of the outputs of the video demodulation circuit 2 is a video signal a, which is input to the a-side contact of the interlocking switch 7. The other output becomes a detection signal and is input to a decoder (not shown).

Similarly, the output of the QPSK demodulation circuit 3 to which the FM demodulation signal from the BS tuner 1 has been input becomes a bit stream signal, which is input to the PCM demodulation circuit 4 and also input to a decoder (not shown). The PCM demodulation circuit 4 selects either TV sound or independent sound in accordance with a command from the microcomputer 6 having received the external command signal, and then selects either one of P and P.
Outputs a CM demodulated signal. At the same time, the PCM demodulation circuit 4 reads the video scramble determination data contained in the bit stream signal, and outputs a video scramble determination signal to the microcomputer 6 according to the data.

The microcomputer 6 receiving the scramble judgment signal
Corresponds to whether or not the video is scrambled, and outputs an interlocking switch control signal. The interlocking switch control signal is input to the interlocking switch 7, and the interlocking switch 7 receiving the signal is connected to the a side when video scrambling is not applied, and the b is connected when video scrambling is applied. Connected to the side.

A detection signal and a bit stream signal are input to the decoder irrespective of the video scramble state, and the video signal b, the audio signal right b, and the audio signal left b are automatically turned on when the power is supplied to the decoder. Are output, and these signals are input to the b-side terminal of the interlocking switch 7. For example, when the PCM demodulation circuit 4 determines that video scramble is present, the instruction is input to the microcomputer 6 as a video scramble determination signal, and the microcomputer 6 receiving the instruction.
Outputs an interlocking switch control signal to connect the interlocking switch 7 to the b side.

The interlocking switch 7 has a two-input, three-system configuration, and the three switches S1, S2, and S3 are simultaneously switched to the same side according to an interlocking switch control signal. By switching the interlocking switch, it is determined whether the video output signal, the audio output signal right, and the audio output signal left output to the television unit are output directly from the BS tuner unit or output through a decoder. .

[0009]

However, if the interlocking switch is simultaneously switched to the same side only by the PCM demodulation circuit 4 determining the presence or absence of a video scramble signal as described above, the video signal is scrambled. If the audio signal is not scrambled, that is, if, for example, the BS3 channel is selected and the audio mode is selected as the independent mode, the Japanese satellite broadcasting is scrambled and the satellite digital music broadcasting is scrambled. The audio signal passes through the decoder even when it is not used, and the audio signal is degraded.

On the other hand, if the video signal is not scrambled and the audio signal is scrambled, that is, if, for example, the BS3 channel is selected and the audio mode is selected as the independent mode, the Japan Satellite Broadcasting System is used. When the satellite digital music broadcast is scrambled, the interlocking switch 7 is connected to the side a, and the audio signal is not scrambled.

FIG. 5 shows the relationship between the presence / absence of scrambling of satellite broadcasting in a conventional automatic switching circuit and whether or not an output signal to a television unit is passed through a decoder. However, this example is for a case where the BS3 channel independent sound mode is selected.

Since it is determined whether the video and the audio are passed through the decoder only by the presence or absence of the video scrambling,
When the viewer selects satellite digital music broadcasting utilizing only the independent audio mode of the BS3 channel, the scramble of the video is canceled by the decoder, but the audio passes through the decoder even though the scramble is not applied. There is a possibility that the sound may be degraded, and there is a problem that the video is not scrambled, but the audio is not descrambled.

[0013]

According to the present invention, there is provided a bit stream signal detecting means for detecting a bit stream signal from an input FM demodulated signal, and the bit stream signal detected by the bit stream signal detecting means. PCM demodulation means for taking a signal as an input signal and deriving an independent mode or television mode PC signal, a video scramble determination signal and an independent audio scramble determination signal as output signals, respectively, and descrambling the video signal and the audio signal independently. Switching means for selectively switching and outputting the applied signal and the non-applied signal;
The video scramble determination signal and the independent audio scramble determination signal are input signals from the PCM demodulation means,
A television independent audio control signal is output to the CM demodulation means, and the video scramble is output to the switching means.
Generated according to the judgment signal and the independent audio scramble judgment signal.
Made the outputs individually independent separate change-over switch control signal of the video and audio to structure provided with control means for selectively switching control of the switching means.

[0014]

In the video / audio independent switching circuit of the present invention, the PCM demodulation circuit decodes the bit stream signal, determines whether or not each of the video signal and the independent mode audio signal has been scrambled, and gives the data as an instruction to the microcomputer. Thus, even if the scramble situation of the video signal and the independent mode audio signal is different, the video signal and the audio signal can be switched independently by the independent switch, so that the appropriate video signal and audio signal are transmitted to the television unit side. Can be output.

[0015]

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 1 is a BS tuner, 2 is a video demodulation circuit, 3 is a QPSK demodulation circuit, 4 is a PCM demodulation circuit, 5 is a D / A converter, 8 is an independent determination microcomputer, and 9 is an independent changeover switch.

If, for example, the BS3 channel independent sound mode is selected by an external command signal, the independent determination microcomputer 8 receiving the command outputs a tuner control signal to the BS tuner 1.
Output to The BS tuner 1 that has received the tuner control signal from the independent determination microcomputer 8 outputs the FM demodulated signal of the BS3 channel to the video demodulation circuit 2 and simultaneously to the QPSK demodulation circuit 3. The video demodulation circuit 2 that has received the FM demodulation signal outputs a video signal a, and the video signal a is input to the contact a of the switch SW1 of the independent changeover switch 9. At the same time, the video demodulation circuit 2 outputs a detection signal, and the detection signal is output to a decoder (not shown).

Similarly, the FPS input to the QPSK demodulation circuit 3
The M demodulated signal is demodulated into a bit stream signal and output to the decoder and the PCM demodulation circuit 4. The PCM demodulation circuit 4 receives the television independent audio control signal from the independent determination microcomputer 8 and outputs the PCM demodulated signal in the independent audio mode to the D / A converter 5 because the external command signal is in the BS3 channel independent audio mode. I do. PC at the same time
The M demodulation circuit 4 decodes the bit stream signal, determines whether or not the video signal and the independent audio signal are scrambled, and outputs the determination result to the independent determination microcomputer 8 as a video scramble determination signal and an independent audio scramble determination signal.

For example, if the Japanese satellite broadcasting is not scrambled and the digital satellite music broadcasting is scrambled, the video scramble judgment signal from the PCM demodulation circuit 4 outputs a judgment signal indicating no scramble to the independent judgment microcomputer 8. Then, the independent voice scramble determination signal outputs a determination signal indicating that scrambling is present to the independent determination microcomputer 8. At this time, the independent judgment microcomputer 8 sends an independent changeover switch control signal (video) to the independent changeover switch 9 and connects the contact of the switch SW1 to the a side.

On the other hand, an independent changeover switch control signal (voice)
Is also sent to the independent changeover switch, and the switches SW2 and SW3 are respectively connected to the b side. In this state, the video output signal is sent directly from the BS unit to the television unit, and the right and left audio output signals are output through a decoder.

FIG. 2 shows the relationship between the presence / absence of scrambling of satellite broadcasting in the video / audio independent switching circuit of the present invention and whether the output signal to the television unit is a signal passed through a decoder. However, this example is for a case where the BS3 channel independent sound mode is selected. In this case, unlike the above-described conventional system, the video output signal corresponds to the Japanese satellite broadcasting and the audio output signal corresponds to the satellite digital music broadcasting, so that the problem described in the conventional system does not occur.

For example, in FIG. 1, if the television sound of the BS3 channel is selected and the Japanese satellite broadcasting is non-scrambled and the satellite digital music broadcasting is scrambled, a video scramble determination signal which is an output signal of the PCM demodulation circuit 4 is provided. Is determined to be non-scrambled, and the independent audio scramble control signal is determined to be scrambled broadcast.However, when the audio mode is TV, the determination of the video scramble determination signal is used for determination of audio scramble, Even if the independent audio is a scrambled broadcast, the independent determination microcomputer sets the switch SW2 and the switch SW3 to the independent switch control signal (audio).
Instructions to connect to the side.

FIG. 3 is a block diagram showing the presence / absence of satellite broadcast scrambling and the output signal to the television unit when the BS3 channel television / audio mode is selected by the BS tuner unit incorporating the video / audio independent switching circuit of the present invention. This shows the relationship as to whether the signal is passed through or not. When the television audio mode of the BS3 channel is selected, the presence / absence of scrambling of the video signal is the same as the presence / absence of scrambling of the audio signal, so whether the independent audio is scrambled or not is set to the independent switch 9. The same control signal is placed on the input independent switch control signal (video) and the independent switch control signal (audio).

That is, if the switch SW1 is connected to the side a, the switches SW2 and SW3 are also connected to the side a. If the switch SW1 is connected to the side b, the switches SW2 and SW3 are also connected to the side b. You. In the video / audio independent switching circuit of the present invention, as described above, the independent determination PCM demodulation circuit 4 automatically performs the video scramble determination and the independent audio scramble determination, and switches the video signal and the audio signal separately based on the determination. Even if the scramble state of Japanese satellite broadcasting (BS3 channel television audio mode) and satellite digital music broadcasting (BS3 channel independent audio mode) are different, whether the audio signal and the video signal should be passed through the decoder or not should be passed. Since switching can be performed independently, appropriate video and audio can be sent to the television unit. Although the above embodiment is a television with a built-in BS, the same effect can be obtained by providing the video / audio independent switching circuit of the present invention in a BS tuner.

[0024]

Since the present invention has the above-described structure,
The PCM demodulation circuit is provided with a function to perform video scramble determination and independent audio scramble determination.
By separately switching and outputting the video signal and the audio signal using these two determination results, the scrambling can be independently canceled even if the scrambling state of the video and the audio is different. Therefore, it is possible to automatically provide good video and audio without making the viewer troublesome operation.

[Brief description of the drawings]

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

FIG. 2 is an operation explanatory diagram of FIG. 1;

FIG. 3 is another operation explanatory view of FIG. 1;

FIG. 4 is a block diagram of a conventional example.

FIG. 5 is an operation explanatory diagram of FIG. 4;

[Explanation of symbols]

 3 QPSK demodulation circuit 4 PCM demodulation circuit 8 Microcomputer 9 Independent switch

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04N 7/16

Claims (1)

(57) [Claims] 1. A bit stream signal detecting means for detecting a bit stream signal from an input FM demodulated signal, and the bit stream signal detected by the bit stream signal detecting means as an input signal, a PC signal in an independent mode or a television mode, PCM demodulation means for deriving a video scramble determination signal and an independent audio scramble determination signal as output signals, respectively, and switching for selectively switching and outputting independently and descrambled signals for video and audio signals, respectively. Means,
The video scramble determination signal and the independent audio scramble determination signal are input signals from the PCM demodulation means,
A television independent audio control signal is output to the CM demodulation means, and the video scramble is output to the switching means.
Generated according to the judgment signal and the independent audio scramble judgment signal.
Video and audio independently switching circuit, characterized in that a control means for selectively switching control of the switching means outputs the made video and individually separate independent changeover switch control signal of a voice.