JPH04200087A - Satellite broadcast receiver image quality display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a satellite broadcast receiver, and more particularly to a satellite broadcast receiver image quality display device that displays the image quality of a received signal.

Conventional technology satellite broadcasting modulates microwave band radio waves with a television signal, radiates the radio waves from a geostationary satellite, and converges the radio waves on the ground with a satellite broadcasting antenna 31 such as a parabolic antenna, as shown in Figure 4. Thereafter, the frequency is converted to the IGHz band using a satellite broadcast converter 32 including an ultra-low noise amplifier. The output signal from the satellite broadcast converter 32 is sent to an indoor satellite broadcast receiver 34 using a coaxial cable 33.
At this point, signal processing such as channel selection and FM demodulation is performed, and a video signal and an audio signal are output, and these are input to the television receiver 35.

By the way, a satellite broadcasting receiver image quality display device is configured as shown in FIG. 5, for example. In FIG. 5, l is a 1stlF input terminal that inputs a signal from the satellite broadcasting converter 32 via a coaxial cable, 2 is a tuning circuit that selects only one channel from a large number of channels, and 3 is an FM input terminal.
FM demodulation circuit for demodulating the modulated signal, 4
does not include the video signal luminance component, the video carrier color signal component, and its harmonic components from the output signal component of the FM demodulation circuit 3,
and a bandpass filter that extracts only the noise component that does not include the modulated signal component of the audio subcarrier; 5 is an amplifier connected to the bandpass filter 4 to amplify the noise component; 6 is connected to the amplifier 5 to measure the magnitude of the noise component; 12 is a DCC level conversion circuit connected to the output terminal of the detector 6 and converts the DC level; 13 is a DCC level converter circuit for superimposing information such as channels on the video signal and displaying it on the television receiver 16; This is an onnu clean display circuit.

In the current satellite broadcasting, the signal after FM reduplication consists of a video luminance component, a video carrier color signal component (center frequency is 3.58 MHz), and an audio subcarrier modulation signal component (center frequency consists of 5.7272 MHz).

Therefore, the bandpass filter 4 for extracting only the noise component without demodulating signal components is used to remove the demodulated signal component and extract only the noise component. Considering the generation of wave components, the center frequency is selected to be approximately 8 MHz and the band to be approximately 1 MHz. By extracting only the noise component with this bandpass filter 4, and then amplifying and detecting it, the amount of noise component is detected,
The on-screen display circuit 13 displays the image quality status of the received signal.

Problems to be Solved by the Invention However, in the above configuration, only the current satellite broadcasting is considered, so M
When receiving a high-definition television broadcast using a USE signal, the MUSE signal component itself is included in the output of the bandpass filter 4 for extracting only the noise component, so there is a problem that the amount of noise component cannot be detected. Was.

In view of the above-mentioned problems, the present invention aims to provide a satellite broadcast receiver image quality display device that operates stably even when receiving high-definition television broadcasts.

Means for Solving the Problems In order to solve the above problems, the satellite broadcasting receiver image quality display device of the present invention includes an FM demodulation demodulator for demodulating satellite broadcasting, an FM
MU that detects the presence or absence of the MUSE signal from the output of the repeater
The SE signal detector and the FM demodulator extract only noise components that do not include the video signal luminance component, the video carrier color signal and its harmonic components, and do not include the modulation signal component of the audio subcarrier. 1 bandpass filter,
a first amplifier connected to the first bandpass filter to amplify a noise component; a first detector to detect the magnitude of the output noise component of the first amplifier; and a first detector connected to the first bandpass filter. a second bandpass filter that extracts a noise component that does not include the MtJSE signal component from the output noise component;
a second amplifier connected to the second handbus sulter to amplify a noise component; a second detector to detect the magnitude of the output noise component of the second amplifier; and an output of the first detector. a switching circuit that is connected to the terminal and the output terminal of the second detector and switches and outputs two signals based on the output of the MUSE signal detector; and a level display that operates in accordance with the output voltage of the switching circuit. Consists of circuits.

Effect of the present invention With the above-described configuration, even when receiving satellite high-definition television broadcasting using the MUSE signal, the MU
The detection signal of the SE signal detector automatically switches the bandpass filter that extracts the noise component from the demodulated signal component, making it possible to detect the noise component from the demodulated signal component in the same way as when receiving current satellite broadcasting. Similar to when receiving satellite broadcasts, the image quality can be displayed even when receiving satellite high-definition television broadcasts using the MUSE signal.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a satellite broadcasting receiver image quality improvement device according to an embodiment of the present invention.

In FIG. 1, 1 is a ]5tlF input terminal, 2 is a tuning circuit, 3 is an FM demodulation circuit, 4 is a first bandpass filter, 5 is a first amplifier, 6 is a first detector, and 12 is a The DC level conversion circuit 13 is an on-screen display circuit, which has the same structure as that shown in FIG. 5.

7 is a second band-pass filter that extracts only the noise component that does not include the MUSE signal component from the output signal component of the FM demodulation circuit 3; 8 is a second band-pass filter that is connected to the second band-pass filter and amplifies the noise component; 9 is a second detector connected to the second amplifier 8 and detects the magnitude of the noise component; 10 is a MUSE signal detector that detects the presence or absence of a MUSE signal; 11 is the output of the first detector 6; This is a switching circuit connected to the output terminal of the second detector 9 and the output terminal of the M tJ SE signal detector 10 to switch between the two signals.

The operation of the satellite broadcasting receiver image quality modification apparatus configured as described above will be explained below.

First, a received signal inputted to the 1stlF input terminal 1 of the satellite broadcasting receiver is selected by the channel selection circuit 2, and FM demodulated by the FM demodulation circuit 3, and then sent to the video signal processing circuit 14 and the audio signal processing circuit 15 After obtaining a video signal and an audio signal in the on-screen display circuit 13 and superimposing information such as channel 2, small display, and volume on the video signal, the television receiver 1
Supply to 6. The circuit operation to date is included in the functionality of a normal satellite broadcast receiver.

Now, the signal of the FM demodulator is as shown in Fig. 2 in satellite broadcasting using the current NTSC system, and the first bandpass filter 4, which removes the demodulated signal component and extracts only the noise component, is conventionally used. The center frequency is set to approximately 8, taking into consideration the generation of harmonic components twice or three times the video carrier color signal and twice the audio subcarrier modulation signal that go to the demodulator circuit.
It is desirable to select the M tlz and band to be around IMI. The noise extracted by the first bandpass filter 4 is amplified by the first amplifier 5 until it reaches a level sufficient to be detected by the first detector 6, and is input to the first detector 6, where it is detected. be done.

As shown in FIG. 3, the highest frequency of the MLiSES signal for satellite high-definition television broadcasting is approximately 9.0 MHz, unlike the current satellite broadcasting signal shown in FIG. For this reason, it is desirable that the second bandpass filter 7, which removes the demodulated signal component and extracts only the noise component, has a center frequency of approximately 10.5 MHz and a band of approximately IMHz. The noise extracted by the first bandpass filter 4 is amplified by the first amplifier 5 to a level sufficient to be detected by the first detector 6.
The signal is input to the detector 6 and detected. Similarly, the noise extracted by the second bandpass filter is
The signal is amplified by the amplifier 8 until it reaches a level sufficient for detection, and then sent to the second detector 9, where it is detected. M
The presence or absence of the MUSE signal is detected by the tJSE signal detector 10, and the switching circuit 11 is controlled by the output of this detection signal.
If there is no MUSE signal, that is, in the case of current satellite broadcasting, the output of the first detector 6 is selected, and if there is a MUSE signal, that is, in the case of satellite high-definition television broadcasting, the output of the second detector 9 is selected. , it is possible to display the received image quality even in the case of satellite high-definition television broadcasting.

Note that since the frequencies to be detected are different, in consideration of the detection efficiency of the detector, an amplifier and a detector were connected to the outputs of the first band-pass filter 4 and the second band-pass filter, respectively. The configuration may be such that the bands of the two bandpass filters are changed, a switching circuit is connected after the two bandpass filters, and the amplifier and the detector are shared.

Effects of the Invention As described above, the present invention switches the bandpass filter that extracts the noise component from the demodulated signal component according to the detection signal of the MUSE signal detector even when receiving satellite high-definition television broadcasting using the MUSE signal. The noise component can be detected from the demodulated signal component in the same way as when receiving satellite broadcasting, and the noise component can be detected from the demodulated signal component in the same way as when receiving satellite broadcasting.
Even when receiving satellite high-definition broadcasting using SE signals, the received image quality can be displayed, which has a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a satellite broadcasting receiver image quality display device according to an embodiment of the present invention, FIG. 2 is a spectrum diagram of a demodulated signal in the demodulated output of a satellite broadcasting receiver when receiving current satellite broadcasting, and FIG. 3 1 is a demodulation spectrum diagram of the demodulated output of a satellite broadcasting receiver when receiving satellite high-definition television broadcasting, FIG. 4 is a diagram of a satellite broadcasting receiving system, and FIG. 5 is a block diagram of a conventional satellite broadcasting receiver. 3...FM demodulation RW, 4...First band pass filter (BPF), 5...First amplifier, 6...First detection device, 7...Second band pass filter (BPF), 8...
・Second amplifier, 9...Second detector, lO・
...MUSE signal detector, 11...
・Switching circuit. Name of agent: Patent attorney Akira Okaji and 2 others 1m4

Claims (1)

[Scope of Claims] An FM demodulator that demodulates satellite broadcasting; a detection circuit that detects a MUSE signal from the output of the FM demodulator; and a video signal luminance component and a video carrier color signal component from the output signal component of the FM demodulator. a first band-pass filter that extracts only noise components that do not include harmonic components thereof and do not include modulated signal components of voice subcarriers; and a first band-pass filter that is connected to the first band-pass filter and amplifies the noise components. a first amplifier that detects the magnitude of the output noise component of the first amplifier; and a first detector that detects the magnitude of the output noise component of the first amplifier;
a second bandpass filter that extracts only noise components that do not include SE signal components; a second amplifier that is connected to the second bandpass filter and amplifies the noise components; and an output noise component of the second amplifier. a second wave detector that detects the magnitude of the MUSE signal detector; and a second wave detector that takes the output signal of the MUSE signal detector as an input to a switching control terminal and is connected to the output end of the first wave detector and the output end of the second wave detector. A satellite broadcasting receiver image quality display device comprising: a switching circuit that selects and outputs one of the output signals of both detectors; and a level display circuit that operates in accordance with the output level of the switching circuit.