JPH03166877A - Television receiver - Google Patents

Abstract

PURPOSE:To eliminate the need for switching the audio signal separately in matching with the switching of a video signal and to eliminate the need for a signal switch by providing an audio signal changeover circuit switching an external audio signal and an output of an audio decoder with an audio synchronizing detection signal. CONSTITUTION:An audio decoder 16 extracts an audio signal multiplexed for a vertical blanking period of a MUSE signal and demodulates the signal. An audio output of the audio decoder 16 and an external audio signal are inputted in an audio signal changeover circuit 21. Then the said two input signals are outputted switchingly by using an audio synchronizing detection signal detected by the audio decoder 16. That is, when the synchronization of the audio signal superimposed on the MUSE signal is locked, the output of the circuit 21 is an audio output of the audio decoder 16 and when no audio signal exists in the MUSE signal and the synchronization is not locked, the external audio signal is automatically selected. Through the constitution above, when no audio signal is superimposed on the MUSE signal, since the switch is thrown to the position of the external audio signal input terminal automatically, no signal switch is required.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a television receiving device used to receive MUSE television signals broadcast in the MUSE system, which is one of the transmission systems for high-definition television. It is something.

Conventional technology High-definition television displays detailed images on a large wide screen to provide new appeal, such as power and realism that cannot be obtained with current television broadcasting. The high-definition television proposed by the Japan Broadcasting Corporation (NHK) has 1125 scanning lines and an aspect ratio of 16, whereas the current standard television system has 525 scanning lines and an aspect ratio of 4:3. :9, and has about 5 times the amount of information.

When broadcasting such high-definition television signals, the upper limit of the signal bandwidth that can be transmitted within the satellite broadcasting channel width of 27 MHz is about 9 MHz, so considerable band compression is required. One of the band compression technologies is MUSE (Multiple Sub-Nyqu).
ist SamplingEncode) method. This method performs subsampling twice to reduce the amount of information sent in one field, and transmits one screen worth of information over four fields. On the receiving side, a memory is used to reproduce one complete field using information for four fields.

A device that restores this MUSE signal to the original television signal is called a MUSE decoder. Let's discuss the MUSE signal in more detail. FIG. 2 shows the transmission signal format of the MUSE signal. As shown in Figure 2, the MUSE signal is a color difference signal (R-Y and B-Y) that is time-compressed to 174 and is alternately inserted between the luminance signal Y and the horizontal synchronization signal HD for each scanning line. ing. That is, the signals are multiplexed on the time axis to form a single signal. The audio signal is also sent during the vertical planking period.

In order to receive broadcasts sent using the MUSE method, a system like the one shown in FIG. 3 is required. 1 is a BS antenna, 2 is a BS converter, and 3 is a BS tuner. Select the MUSE signal with the BS tuner, and then
input to the decoder 6.

As an input to the MUSE decoder 6, in addition to the BS tuner 3, a knMUsE system VTR 4, a MUSE system video disc 5, etc. can be considered. MU by MUSE decoder 6
The SE signal is converted into a high-definition original signal and displayed on a high-definition display 7.

Here, the operation of the MUSE decoder 6 will be briefly explained.

In FIG. 3, an input signal is selected at 8, and a synchronization signal is separated at 9. Video signals are divided into still image processing and video processing. For still images, the frame memory 10 is used to restore the original high-definition signal using signals for four fields (still area interpolation 11), but for moving images, one field of the four fields is restored to prevent blurring of the image. Spatial interpolation processing is performed using only the signals (moving area interpolation 12). Then, the mixing circuit 13 generates a still image according to the output of the motion detection 14. Mix videos. Then, the color difference signal is time-expanded and demodulated by the TCI decoder 15. Further, the audio signal is demodulated by the audio decoder 16.

Problems to be Solved by the Invention However, with the above configuration, the MUSE method V
MU audio signals with TR, MUSE format video discs, etc.
If the signal is not sent along with the SE signal but is independently reproduced and output, the following problems arise.

Figure 4 shows the input terminal A17 and input terminal B1 of the MUSE decoder for a BS tuner and a MUSE type VTR, respectively.
8 is input. At this time, the MUSE method VTR
It is assumed that the output MUSE signal does not include an audio signal. In that case, if you switch input A and input B with the MUSE decoder, audio will be output from the MUSE decoder when the BS tuner is selected, but when the MUSE
When a system VTR is selected, audio is output from the MUSE system VTR. Therefore, MUSE decoder and MUS
A signal switch 19 is required which receives the respective audio outputs of the E-scheme VTR as two inputs, and there is a problem in that the signal switch 19 must be switched at the same time as the MUSE decoder switches the signal.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a television receiver that can automatically switch audio simply by switching signals using a MUSE decoder.

Means for Solving the Problems In order to solve the above problems, the receiving device of the present invention has M
Depending on the presence or absence of an audio synchronization detection signal connected to an audio decoder inputting the USE signal, an external audio input terminal, an audio output terminal of the audio decoder, and the external audio signal input terminal and detected by the audio decoder, It is equipped with an audio signal switching circuit that switches and outputs the audio output of the audio decoder and an external audio signal.

According to the above-described configuration, the present invention detects whether or not there is an audio signal in the MUSE signal using the audio synchronization detection signal of the audio decoder, and when there is an audio signal, switches the audio signal switching circuit to the audio decoder side, and switches the audio signal switching circuit to the audio decoder side. By switching to the external audio signal side when there is no audio signal, there is no need to connect an external signal switcher, and since the presence or absence of an audio signal is detected and automatically switched, operation is simplified.

Embodiment Hereinafter, a receiving apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram of a receiving device in an embodiment of the present invention. In FIG. 1, 16 is an audio decoder, 20 is an external audio signal input terminal, and 21 is an audio signal switching circuit.

The operation of the embodiment configured as above will be explained. The audio decoder 16 extracts and demodulates the audio signal multiplexed during the vertical blanking period of the MUSE signal. The audio output of the audio decoder 16 and an external audio signal are input to the audio signal switching circuit 21 . Then, based on the audio synchronization detection signal detected by the audio decoder 16,
The two input signals are switched and output. That is, M.U.
When an audio signal is multiplexed on the SE signal and the audio synchronization is locked, the output of the audio signal switching circuit 21 becomes the audio output of the audio decoder 16, and when there is no audio signal on the MUSE signal and the synchronization is not locked. automatically switches to external audio.

With this configuration, when no audio signal is multiplexed to the MUSE signal, the switch is automatically switched to the external audio signal input terminal side.
Even when connecting two TR or video discs and switching between them, there is no need to use a signal switch for audio.

Effects of the Invention As described above, the present invention provides an audio signal switching circuit that switches between external audio and the output of an audio decoder using an audio synchronization detection signal, thereby eliminating the need to separately switch the audio when switching the video signal. Moreover, a signal switcher can also be made unnecessary.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the main parts of a television receiver according to an embodiment of the present invention, FIG. 2 is a transmission signal format diagram of a MUSE signal, FIG. 3 is a diagram of a MUSE broadcast receiving system, and FIG.
The figure shows a conventional MUSE decoder with a BS chiner and MUS.
It is a system configuration diagram when connecting an E-scheme VTR. 1...BS antenna, 2...BS converter, 3...BS tuner, 4...
・MUSE system VTR, 5...MUSE system video disc, 6...MUSE decoder, 7.
...High-definition display, 16...
・Audio decoder, 19...Signal switch, 20・
...External audio signal input terminal, 21...Audio signal switching circuit.

Claims (1)

[Claims] an audio decoder receiving a MUSE system television signal as input, an external audio signal input terminal, an audio output terminal of the audio decoder and the external audio signal input terminal,
A television receiver comprising: an audio signal switching circuit that switches and outputs the audio output of the audio decoder and an external audio signal depending on the presence or absence of an audio synchronization detection signal detected by the audio decoder.