JPH02138876A - Checking device of reception sensitivity level - Google Patents

Abstract

PURPOSE:To enable easy checking of a reception sensitivity level by providing an AD converter whereby a DC voltage outputted from an FM demodulator in a receiver of direct satellite broadcasting is converted into a digital signal. CONSTITUTION:In a receiver of direct satellite broadcasting, a signal level voltage outputted from an FM demodulator 1 of a second IF element and varying in accordance with a reception sensitivity level is inputted to an AD converter 2. When the direction of a BS antenna is adjusted on the occasion, the signal level voltage outputted from the FM demodulator 1 is varied therewith. A single frequency signal generated in an attenuator 4 is varied in accordance with the variation of this voltage, and the signal is amplified by a filter amplifier 9 and outputted as a strength of a sound from a speaker 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a receiving sensitivity level confirmation device for confirming the receiving sensitivity level in a direct satellite broadcast receiver.

[Conventional technology]

A BS antenna connected directly to a satellite broadcasting receiver requires high gain in order to receive weak radio waves from broadcasting satellites. Furthermore, since BS antennas are very sensitive to radio waves, if the direction toward the broadcasting satellite is slightly shifted, the reception level will drop extremely, resulting in significant deterioration of video and audio. Therefore, it is necessary to accurately adjust the direction of the BS antenna.

In adjusting the direction of the BS antenna, the elevation angle, azimuth angle, and installation position relative to the broadcasting satellite are adjusted, but the final fine adjustment is performed so that the satellite broadcasting is actually received and the receiving sensitivity level is the best.

To check the receiving sensitivity level, check the 2n of the direct satellite broadcast receiver.
d Since the IF section outputs a signal level voltage that changes according to the reception sensitivity level, this can be checked with a measuring device such as a tester, or with a level meter with an LED display that is driven by the signal level voltage. It had been confirmed.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional reception sensitivity level confirmation device, the reception sensitivity level displayed by a level meter etc. must be directly visually confirmed.
When the S antenna is installed far away from the direct satellite broadcasting receiver, it is difficult to check the receiving sensitivity level while adjusting the direction of the BS antenna.

[Means to solve the problem]

In order to solve the above problems, the reception sensitivity level confirmation device according to the present invention includes an AD converter that converts a DC voltage output from an FM demodulator in a direct satellite broadcast receiver into a digital signal, and an output of the AD converter. a data conversion circuit that converts data into data that becomes smaller as the DC voltage increases; a single frequency signal generating means that generates an encoded single frequency signal; a multiplication means for multiplying the frequency signal; a DA converter for converting the output signal from the multiplication means into an analog signal; an amplification means for amplifying the analog signal output from the DA converter; The present invention is characterized in that it is equipped with a sound generating means for generating sound at a high volume.

[For production]

With the above configuration, the FM demodulator of the direct satellite broadcasting receiver outputs a DC voltage according to the receiving sensitivity level, and this DC voltage is converted into a digital signal by the AD converter. The output data of the AD converter is converted by a data conversion circuit into data that decreases as the DC voltage increases. The data obtained here is multiplied by the multiplication means with the encoded single frequency signal generated in the single frequency signal generation means, and a single frequency signal corresponding to the receiving sensitivity level is generated. . Since this single frequency signal is a digital signal, it is converted into a 7-analog signal by a DA converter, amplified by an amplifying means, and then outputted as audible by a voice ordering means. Since this sound changes in strength depending on the receiving sensitivity level, the receiving sensitivity level can be confirmed even from a far away location.

Furthermore, since the single frequency signal that changes depending on the receiving sensitivity level is processed as a digital signal, the configuration can be simplified and integration can be facilitated.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 and 2.

As shown in Figure 1, in a direct satellite broadcast receiver, 2n
A signal level voltage that is output from the FM demodulator 1 of the dlF section and changes depending on the receiving sensitivity level is input to the AD converter 2. Output data of the AD converter 2 is connected to an attenuator 4 via a data conversion circuit 3. The AD converter 2 is a circuit that quantizes the input signal level voltage into n bits (for example, 6 to 8 bins 1-). As shown in FIG. 2, the data conversion circuit 3 is a circuit that converts the output data from the AD converter 2 into data that decreases as the signal level voltage increases. The attenuator 4 is a circuit that multiplies the output data from the data conversion circuit 3 by a single frequency signal sent from the ROM 6, which will be described later, to generate a single frequency signal having a size corresponding to the receiving sensitivity level.

On the other hand, the count signal of the address counter 5 is sent to the ROM 6, and a single frequency signal is sent from the ROM 6 in response to this signal. The ROMfi stores encoded single frequency signals (for example, a 1 kHz sine wave) in advance, and sequentially sends them to the attenuator 4 according to the count signal of the address counter 5.

The single frequency signal sent out from the attenuator 4 is connected to the DA converter 8 via the switch 5WXDA converter interface 7. The switch SW is
It is designed to switch between the PCM audio signal output from the PCM audio processing section of a direct satellite broadcasting receiver (not shown) and the PCM single frequency signal sent from the attenuator 4, and is connected to the A terminal during normal reception. , is connected to terminal B when checking the receiving sensitivity level. The DA converter interface 7 is a circuit that serves as an interface between the anti-digital converter 4 and the DA converter 8. D
The A converter 8 is a circuit that converts a PCM single frequency signal into an analog audio signal.

An analog audio signal from the DA converter 8 is connected to a speaker 10 via a filter amplifier 9. The filter amplifier 9 is an amplification means that is provided externally and amplifies an analog audio signal to a size that can be reproduced by the speaker 10. The speaker 10 is a sound generating means that generates sound at a volume corresponding to the sound signal amplified by the filter amplifier 9.

In the above configuration, when the direction of the BS antenna (not shown) is adjusted, the signal level voltage output from the FM'tl adjuster 1 changes accordingly.

When the signal level voltage changes depending on the direction of the BS antenna, the single frequency signal generated by the attenuator 4 changes accordingly, is amplified by the filter amplifier 9, and is output from the speaker 10 as a sound intensity.

[Effects of the Invention] As described below, the reception sensitivity level confirmation device according to the present invention includes an AD converter that converts a DC voltage output from an FM demodulator in a direct satellite broadcast receiver into a digital signal, and an AD A data conversion circuit that converts the output data of the converter into data that decreases as the DC voltage increases; a single frequency signal generating means that generates an encoded single frequency signal; and an output of the data conversion circuit. a multiplier for multiplying the signal by the single frequency signal; a DA converter for converting the output signal from the multiplier into an analog signal; an amplification means for amplifying the analog signal output from the DA converter; This configuration includes a sound generating means for generating sound at a volume corresponding to the sound signal.

Changes in the DC voltage output from the FM demodulator due to dust are superimposed on the encoded single frequency signal and converted into the strength of the audio, so the receiving sensitivity level can be confirmed by audio alone, without visual inspection. be able to.

Therefore, even if the direct satellite broadcast receiver and the BS antenna are far apart, the reception sensitivity level can be easily checked.

In addition, since the single frequency signal is processed as a digital signal, the configuration can be simplified and integration can be facilitated, and the effect is that it can be easily incorporated into a direct satellite broadcasting receiver. play.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, in which FIG. 1 is a block diagram showing the configuration of a reception sensitivity level confirmation device, and FIG. 2 shows output data and signal levels of a data conversion circuit. It is a graph showing the relationship between voltages. 2 is an AD converter, 3 is a data conversion circuit, 4 is an attenuator, 5 is an address counter (single frequency signal generation means), 6 is ROM (single frequency signal generation means), 8 is D
A converter, 9 is a filter amplifier (amplification means), 10
is a speaker (sound generating means).

Claims (1)

[Claims] an AD converter that converts a DC voltage output from an FM demodulator in a direct satellite broadcast receiver into a digital signal; a data conversion circuit that converts output data of the AD converter into data that decreases as the DC voltage increases; a single frequency signal generation means for generating an encoded single frequency signal; a multiplication means for multiplying the output data of the data conversion circuit by the single frequency signal; and converting the output signal from the multiplication means into an analog signal. The present invention is characterized by comprising a DA converter, an amplifying means for amplifying an analog signal output from the DA converter, and a sound generating means for generating sound at a volume corresponding to the sound signal amplified by the amplifying means. Receiving sensitivity level confirmation device.