JPS6277769A - Television signal receiver - Google Patents

Abstract

PURPOSE:To improve operability by changing over a sound signal from a converting circuit for making the sound signal of other system and the sound signal of a standard system the same formation and the sound signal of a TV signal of a standard system by a switch circuit to make output paths of the sound signals common. CONSTITUTION:When a TV signal of a standard system is received, a direct current output is obtained in a sub-scarrier detecting circuit 21 and the obtained detecting output changes over an analog switch circuit 22 to a standard system side. Then a base band signal is inputted to a sub-carrier QPSK demodulating circuit 11 through the circuit 22 and a sound signal is outputted from a tuner 19. When a high grade TV signal of an MUSE system is received, even if the base band signal from an FM demodulator 5 is inputted to a switch circuit 10, a sub-carrier signal is not present therein, so that a detecting signal is not obtained from the circuit 21 and the circuit 22 is changed over to a high definition side. The third IE signal from the third converter 8 is inputted to a sub- carrier QPSK modulating circuit 18 to form a QPSK modulated wave and demodulate the sound signal from the circuit 11.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is directed to a television signal reception method that receives a general standard television signal and a high-definition television signal such as the MUSE system in television broadcasting using a broadcasting satellite. It's about machines.

(Prior art) Television broadcasting using broadcasting satellites has already been carried out, and its standard method is a video signal bandwidth of 4.5 MHz and an audio signal bandwidth of 2.048 Mb/s r7).
M code, and performs four-phase phase modulation on the 5.73 MHz subcarrier to create a QPSK signal, and the Q of the video signal and audio signal is
The baseband signal frequency-multiplexed with the PSK signal is FM
It is modulated and transmitted with an RF signal bandwidth of 27MHz.

On the other hand, experimental high-definition television broadcasting is about to begin using the MUSE system developed by NHK.
The system uses a high-definition television signal with a bandwidth of 30 MHz as a band-compressed 8 MHz video signal, and the audio signal uses a 2.048 Mb/s PCM code, which is the same as satellite broadcasting, and this PCM code is approximately 1/2 16, phase modulated to create a QPSK signal, and Q of the video signal and audio signal.
PSK signal and RF TDM (Radio F
requency Time D 1vision
Multiplex) is used for time division multiplexing.

The video signal is an FM modulated wave, and the vertical blanking period increases the data rate of the packet-like audio data signal to approximately 32M.
Time division multiplexing with QPSK modulated waves compressed to b/s,
It transmits with an RF signal bandwidth of 27MHz.

Such high-definition television signals can be transmitted using current broadcasting satellites, and high-definition television can be achieved by attaching a special adapter for high-definition television to a satellite broadcasting receiver that is already in practical use. Broadcasts can be received.

FIG. 5 shows an outline of a receiver for receiving satellite broadcasting, that is, standard format television signals and MUSE format high-definition television signals. 18 is a tuner that receives satellite broadcasting, 20 is a MUSE decoder that demodulates a video signal etc. from a high-quality television signal, 25 is a parabolic antenna, and 26 is a converter that performs frequency conversion. A 12 GHz band television signal from a broadcasting satellite is received by a parabolic antenna 25 and input to a converter 26.
6, the frequency is converted into a first IF signal in the IGHz band. The converter 26 is attached to a parabolic antenna 25, and the LIF is connected from the converter 26 installed outdoors to the tuner 18 installed indoors through a coaxial cable.
It transmits signals and prevents signal loss in coaxial cables by frequency conversion. The tuner 18 selects the desired channel of the TV signal from the first IF signal, converts the frequency to the second IF signal, demodulates the second IF signal when receiving a standard TV signal, and converts the video signal and audio. The video signal is input to an AV child television imager, and the audio signal is input to stereo audio equipment. In the case of a high-definition television signal, the baseband signal obtained by FM demodulating the second IF signal and the third IF signal obtained by frequency-converting the second IF signal are input to the MUSE7'' Cog 20, and the baseband signal is converted into a high-definition video signal. Also, the third I
The audio signal is demodulated from the F signal, the high-definition video signal is sent to a high-definition display monitor, and the audio signal is sent to the stereo sound l1.
input into the device.

A detailed block diagram of the above-mentioned television signal receiver is shown in FIG. 1 is a second converter, 2 is a second local oscillator, 3 is a tuning device that controls the oscillation frequency of the second local oscillator 2, 4 is a second IF amplifier, 5 is an FM demodulator, 6 is a de-emphasis/LPF circuit, 7 is a clamp video amplifier, 8 is a third converter, 9 is a third local oscillator, 11 is a subcarrier QPSK demodulation circuit, 12 is a PCM processor, 13.
14 is a D/A conversion circuit, 15 is a MUSE video decoder,
1B is a QPSK demodulation circuit, 17 is a time expansion circuit that restores the compressed signal, 27 is a PCM processor, 28.
Reference numeral 29 indicates a D/A conversion circuit.

The first IF signal from the converter 2B is input to the second converter 1 of the tuner 18, and to the second converter 1, an oscillation signal is applied from the second local oscillator 2 whose oscillation frequency is controlled by the tuner 3, and a mixing operation is performed. For example 402
．． Only the television signal whose frequency is converted to the second IF signal of 78 MHz is selected. The second IF signal is sent to the second IF amplifier 4.
The second IF amplifier 4 is equipped with a bandpass filter with a passband width of one channel, AGC to stabilize the output level, and a limiter function, and amplifies the second ``xF'@'' signal to a predetermined level. It outputs to the FM demodulator 5 and the third converter 8.The FM demodulator 5 has a discriminator,
Alternatively, it is configured with a PLL circuit or the like, and extracts a baseband signal including a video signal and an audio signal from the second IF signal.

Here, if the received TV signal is a standard TV signal, the demodulated baseband signal is input from the FM demodulator 5 to the de-emphasis/LPF circuit 6, where the video signal is extracted and subjected to de-emphasis processing. Clamp/
input to video amplifier 7; Clamp video amplifier 7
Then, the video signal is clamped to a predetermined level, the NTSC composite signal is converted to P-PIV, and the signal is output from the video output terminal of the tuner 18. Further, as for the audio signal, the demodulated baseband signal is input to the subcarrier QPSK demodulation circuit 11, and the subcarrier QPSK demodulation circuit 11
．． The 73 MHz audio subcarrier is extracted and QPSK demodulated data with a data rate of 2.048 Mb/s is obtained by quadrature phase detection, carrier recovery, and clock recovery functions, and this QPSK demodulated data is sent to the PCM processor 12.
The PCM processor 12 performs error correction, data rearrangement, etc. to obtain PCM code audio data, and the PCM code audio data is input to the D/A converter 13.1.
4, the digital signal is converted into an analog audio signal, and the audio signal is output from the audio output terminal of the tuner 19.

The TV audio signal is output from the Naori/A converter 13, and also from the D/A converter 13.
An additional audio signal is output from the A converter 14.

If the received television signal is a high-quality MUSE television signal, the baseband signal demodulated by the FM demodulator 5 is transmitted with the video signal period FM modulated, so it is a MUSE baseband signal that is only a video signal. There is MUS
input to the MUSE video decoder 15 of the E decoder 20,
In addition, in order to extract the audio signal, the second IF signal is
The signal is input from the F amplifier 4 to the third converter 8, and the third converter 8 receives the oscillation signal from the third local oscillator 9 and converts the frequency into a third IF signal of, for example, 140 MHz.
The third IF signal is input to a circuit of the MUSE decoder 20 that processes audio signals. MUSE baseband signal is MU
The original 30 MHz band is input to the MUSE video decoder 15 of the SE decoder 20 and compressed to 8 MHz by the MUSE video decoder 15 equipped with a still area interpolation function, a moving area interpolation function, and a motion detection function. It returns to the original width and outputs high-quality video signals to the R, G, and B output terminals.

The MUSE video decoder 15 is a main part of high-definition television broadcast reception, but since it is not directly related to the present invention, a detailed explanation will be omitted. In addition, QPSK modulated waves of audio data are multiplexed in the third IF signal using the RFTDM method, and the QPSK modulated wave of audio data is multiplexed in the vertical blanking period of each field.
A PSK modulated wave is inserted in the form of a packet, and the 3rd IF
The signal is input to the QPSK demodulation circuit 18, and the data is converted into data by the quadrature detection and carrier regeneration function of the QPSK demodulation circuit 16.
) 32 Mb/s is demodulated into packet-like audio data, and the compressed packet-like audio data is input to the time expansion circuit 17 and converted into a data layer.) 2.04
Expands to 8 Mb/S continuous audio data. The time expansion circuit 17 is an RA that stores audio data for one field.
It is equipped with a controller for reading and writing data, and RA transmits 32 Mb/s packet audio data in synchronization with the audio system clock from the MUSE video decoder 15.
High-speed writing to M and 2,048Mb/s
Then, low-speed reading is performed to obtain continuous audio data at a data rate of 2.048. This continuous audio data is subcarrier QPSK in standard television signal reception.
This is the same as the QPSK demodulated data of the demodulation circuit 11, and the subsequent signal processing is the same as in a standard TV signal receiver. That is, the audio data is input to the PCM processor 27, error corrected and data rearranged to obtain PCM encoded audio data, and the D/A converters 28 and 29 obtain analog audio signals. The D/A converter 28 outputs a television audio signal, and the D/A converter 29 outputs an additional audio signal.

(Problems to be Solved by the Invention) The PCM processors 12, 2? The subsequent signal processing and audio signal quality are the same, but both audio signals are separately sent to the tuner 19. There is a problem in that two sets of circuit components output from the MUSE decoder 20 and having the same performance and function are required. In addition, in terms of audio signal quality, the number of quantization bits is compact in the high quality mode (B mode).
It is 16-bit, the same as the disc, and it is normal for audiophiles to connect the audio output to a stereo device to enjoy this high quality audio. Then, when the tuner's channel selection operation switches from standard TV broadcasting to high-definition TV broadcasting, or when the program changes from standard TV broadcasting to high-definition TV broadcasting on the same channel, an audio signal is output. Since the terminals were separate, stereo equipment had to be operated to switch inputs, which caused problems in operability.

The purpose of the present invention was to solve these problems in conventional television signal receivers.The purpose of the present invention is to reduce the cost and size by combining the two same circuits into one. It is an object of the present invention to provide a television signal receiver which realizes this and also improves the operability of stereo equipment because there is only one audio signal output terminal.

(Means for Solving the Problem) In order to achieve the above object, a television signal receiver according to the present invention is a television signal receiver that switches and receives a standard format television signal and another format television signal. , a modulation circuit that converts the audio signal of the other format television signal into the same form as the audio signal of the standard format television signal, and at least one of the standard format television signal or the other format television signal. and a switch circuit that selects between the audio signal of the standard TV signal and the audio signal from the modulation circuit based on the output of the detection circuit. The audio signal output path of the television signal is configured in common.

(Function) A detection circuit that detects at least one of the standard format television signal and the other format television signal detects the audio signal of the other format television signal in the same form as the standard format television signal. Since the switch circuit is used to switch between the audio signal from the modulation circuit that converts the audio signal to the audio signal of the standard TV signal, the audio signal output route can be shared, and there is no duplication between the two systems. The receiver as a whole can be made lower in price and smaller in size.

In addition, since the audio signals of standard TV signals and TV signals of other formats are output from the same route, even if the format of the received TV signal changes, the stereo equipment to which these audio signals are input can be switched. This is not necessary and improves operability.

(Description of Embodiments) Hereinafter, an embodiment according to the present invention will be described in detail with reference to FIGS. 1 and 2, and other embodiments are shown in FIGS. 3 and 4. In FIGS. 1 to 4, the same parts as those in FIGS. 5 and 6 are denoted by the same reference numerals, and redundant explanation will be omitted.

1 and 2, 10 is a switch circuit, 18 is a subcarrier QPSK modulation circuit, 21 is a subcarrier detection circuit, and 22 is an analog switch circuit.
The difference from the conventional example is that a switch circuit 10 and a subcarrier QPSK modulation circuit 1 are newly added, and a PCM processor 27 and a D/A converter 28.28 are removed.

The operation will be explained only for audio signals.

When receiving a standard television signal, the baseband signal from the FM demodulator 5 is input to the switch circuit IO. The switch circuit 10 is composed of a subcarrier detection circuit 21 and an analog switch circuit 22, as shown in FIG. A baseband signal is input to the carrier detection circuit 21, a 5.73MHz subcarrier is extracted and amplified by a bandpass filter, and DC output is obtained by detection and amplification. Detect whether a signal is being received.

When a standard television signal is being received, a DC output is obtained in the subcarrier detection circuit 21, and this DC output becomes a detection signal to control the analog switch circuit 22.
Switching to the standard method side, the baseband signal is input to the subcarrier QPSK demodulation circuit 11 via the analog switch 22, and thereafter the audio signal is processed in the same manner as in the conventional example, and the audio signal is output from the tuner 18. . At this time, of course, the high quality side to which the output from the subcarrier QPSK modulation circuit 18 is connected is in the OFF state.

FM when receiving MUSE high-definition TV signals
Even if the baseband signal from the demodulator 5 is input to the switch circuit 10, the baseband signal contains 5.73MHz.
Since there is no subcarrier, a detection signal cannot be obtained from the subcarrier detection circuit 21, and the analog switch circuit 22 switches to the high quality side. The third IF signal from the third converter 8 is transmitted to the QPSK demodulation circuit 16 and the time expansion circuit 1.
7, the resulting data rate is 2.048M.
b/s continuous audio data is input to the subcarrier QPSK modulation circuit 18 to create a QPSK modulated wave that is the same as the audio subcarrier in the standard television signal.
The PSK modulated wave is input to the subcarrier QPSK demodulation circuit 11 via the analog switch circuit 22, audio signal processing similar to that described above is performed, and the audio signal is output from the tuner 19 through the same output terminal as in the standard system. Of course, at this time, the standard method side of the analog switch circuit 22 is OFF.
state.

The analog switch circuit 22 switches between two inputs using a DC control signal, and can be used as long as it can turn on a signal of about 6 MHz.
There are many switching means such as MO3@IC, diode switch, and small relay.

In other embodiments shown in FIGS. 3 and 4, 23 is a switch circuit, 24 is a logic circuit, and a unique digital synchronization signal included in a high-definition television signal is used instead of a baseband signal to detect the reception state. The tuner 18 is left almost untouched, and the MUSE decoder 20 is provided with a switch circuit 23 and the like. When receiving only standard television signals, the tuner 19's baseband signal output and baseband signal input (subcarrier QPS
It is only necessary to connect the input terminal (input of the K demodulation circuit 11) with a coaxial cable, and this type is advantageous in terms of cost when high-definition television broadcasting is in the experimental stage.

The switch circuit 23 is composed of a logic circuit 24 and an analog switch circuit 22, and the logic circuit 24 includes a MUS
A unique digital synchronization signal included in a high-definition television signal is input from the E-video decoder 15, and when a standard television signal is received, since this digital synchronization signal is not present, the output of the logic circuit 24 is 0-level, and M.U.
When receiving a high-definition television signal of the SE system, a digital synchronization signal is detected and the output of the logic circuit 24 becomes a continuous high-level logic level, and this high-level output becomes the detection signal of the high-definition television signal and is activated by the analog switch. The circuit 22 is controlled, and when receiving a standard TV signal, the baseband signal is sent to the subcarrier QPSK demodulation circuit 11 via the analog switch circuit 22 of the switch circuit 23.
When receiving high-definition television using the MUSE system, the output of the subcarrier QPSK modulation circuit 18 is input to the subcarrier QPSK demodulation circuit 11 via the analog switch circuit 22 of the switch circuit 23.

Note that the output of the detection circuit may be used to display whether a standard TV signal or a MUSE high-definition TV signal is being received.

(Effects of the Invention) As explained above, according to the television signal receiver of the present invention, the detection circuit that detects at least one of the standard television signal and the other television signal can detect the other television signal. The switch circuit switches between the audio signal from the modulation circuit that converts the audio signal of the standard TV signal into the same form as the audio signal of the standard TV signal, and the audio signal of the standard TV signal. The output path can be shared, and there is no duplication between the two systems, making it possible to reduce the price and size of the receiver as a whole. In addition, since the audio signals of standard TV signals and TV signals of other formats are output from the same route, even if the format of the received TV signal changes, the stereo equipment to which these audio signals are input can be switched. This is not necessary and has the excellent effect of improving operability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment according to the present invention, FIG. 2 is a detailed block diagram of the switch circuit of FIG. 1, and FIG. 3 is a block diagram showing another embodiment. 4 is a detailed block diagram of the switch circuit of FIG. 3, FIG. 5 is a block diagram of a conventional television signal receiver, and FIG. 6 is a block diagram of the tuner circuit of FIG. and M
FIG. 2 is a detailed block diagram of a USE decoder. 1: Second converter, 2: Second local oscillator, 3: Tuning device, 4: Second IF amplifier, 5: FM demodulator, 6: De-emphasis/LPF circuit, 7: Clamp/video amplifier, 8: Third Converter, 9: Third local oscillator, 10.2
3: Switch circuit, 11: Subcarrier QPSK demodulation circuit, 12: PCM processor, 13.14, 28, 29: D/A converter, 15: M
IJSE video decoder, 1f3: QPSK demodulation circuit, 17: Time expansion circuit, 18
: Subcarrier QPSK modulation circuit, 19: Tuner,
20: MUSE decoder, 21: subcarrier detection circuit, 22: analog switch circuit, 24: logic circuit.

Claims (2)

[Claims] (1) In a TV signal receiver that switches and receives standard TV signals and other TV signals, converts the audio signal of the other TV signal into the same format as the standard TV signal. a modulation circuit for detecting at least one of the standard format television signal or another format television signal; and a detection circuit for detecting at least one of the standard format television signal or another format television signal; 1. A television signal receiver comprising: a switch circuit for selecting an audio signal from a circuit; and a common output path for audio signals of standard television signals and television signals of other formats. (2) The television signal of the other system is a high-definition television signal of the MUSE system, and the signal detected by the detection circuit is a subcarrier obtained by converting the standard system television signal or the high-definition television signal of the MUSE system. The television signal receiver according to claim 1, wherein the television signal receiver is a digital synchronization signal.