JPS59186430A - Receiver for satellite - Google Patents

Abstract

PURPOSE:To adjust the direction of a receiving antenna accurately and easily by knowing the electric field intensity of a radio wave received by the receiving antenna only by connecting a simple instrument to a terminal for testing provided to an outdoor unit. CONSTITUTION:An indoor unit 30 detects the reception level of the radio wave received by the outdoor unit 2 and sends out the detected reception level to the outdoor unit, which is provided with the testing terminal 13 which outputs the reception level supplied from the indoor unit. A low-frequency signal which varies in amplitude with the reception level of the radio wave appears at the testing terminal 13. For this purpose, the amplitude of the low-frequency signal led out to the testing terminal 13 is measured to know the reception level of the receiving antenna 1, i.e. electric field intensity of the received radio wave. Therefore, the direction of the receiving antenna 1 is so adjusted that the indicated value of an AC voltmeter is maximum, installing the receiving antenna 1 accurately in the arrival direction of the radio wave.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a satellite receiver, and in particular to a satellite receiver for direct reception for consumer use, which has a function of accurately orienting a receiving antenna in the direction of incoming radio waves. Regarding.

With the recent information age, it has been proposed that each home directly receive broadcast radio waves relayed by satellites (artificial satellites). Conventionally, as a device for receiving radio waves transmitted from a satellite, there has been a receiving device equipped with an industrial automatic tracking antenna. However, such a receiving device is very expensive and cannot be accepted as a device for direct reception for general consumer use due to its price. In addition, radio waves from satellites generally have a very weak electric field, and the beam width of the receiving antenna is generally very narrow, less than a few degrees. With simple methods, it is extremely difficult to accurately point the antenna in the direction in which the radio waves from the satellite arrive.

Therefore, the main object of the present invention is to provide a satellite receiver that has a very simple and inexpensive configuration and has the ability to accurately and easily install an antenna in the direction of arrival of radio waves transmitted from a satellite. It is to provide.

In summary, this invention includes an outdoor unit and an indoor unit, the indoor unit detects the reception level of radio waves received by the outdoor unit, and sends the detected reception level to the outdoor unit, and the outdoor unit detects the reception level of radio waves received by the outdoor unit. A test terminal is provided so that the received level given by the receiver can be output to the outside. In other words, by connecting, for example, a simple AC voltmeter to the test terminal provided on the outdoor unit, the person installing the antenna can easily determine the reception level, and adjust the reception antenna so that the reception level is the strongest. It was designed so that it could be installed.

The above objects and other objects and features of the present invention will become more apparent from the following detailed description with reference to the drawings.

The drawing is a schematic block diagram showing one embodiment of the present invention. In the figure, a receiving antenna 1 is connected to an outdoor unit 2. In this outdoor unit 2, radio waves received by the receiving antenna 1 are high-frequency amplified and then converted into intermediate frequency signals. The output of outdoor unit 2 is one coaxial cable 2.
0 to the indoor unit 30. The indoor unit 30 demodulates the output given from the outdoor unit 2 into the original television signal. The output of the indoor unit 30 is provided to a television receiver [50] via a coaxial cable 48.

Next, a more detailed configuration of the outdoor unit 2 will be described. This outdoor unit 2, like the receiving antenna 1, is installed outdoors. The output of receiving antenna 1 is R
The signal is given to the F (high frequency) amplifier 3 and is amplified at high frequency. The output of this RF amplifier 3 is given to one input of a mixer 4. The output of the local oscillator 5 is applied to the other input of the mixer 4 . The mixer 4 mixes the output of the RF amplifier 3 and the output of the local oscillator 5 and converts it into a so-called intermediate frequency signal. That is, this embodiment employs a superheterodyne reception method. The output of mixer 4 is the 11th F (middle WA
frequency) is given to the amplifier 6 and amplified. The output of the first IF amplifier 6 is given to a bandpass filter 7. The output of the bandpass filter 7 is given to an output terminal connector 8. Further, this output terminal connector 8 is connected to an input terminal of a low-pass filter 9 via an RF choke coil 14. The output of the low-pass filter 9 is given to a voltage control circuit 11. This voltage control circuit 11 is for dividing the voltage given from the power supply circuit 43 of the indoor unit 30, which will be described later, into various voltage values. and,
The voltage output from the voltage control circuit 11 is used to drive various circuits within the outdoor unit 2.

In addition, the output terminal connector 8 has an RF choke coil 1.
0 and a test terminal 13 via a DC blocking capacitor 12. As will be described in detail later, this test terminal 13 outputs a low frequency signal whose amplitude changes depending on the reception level of the radio wave. Then, a simple AC voltmeter or the like is connected to this test terminal 13 to measure the reception level. Further, the output terminal connector 8 is connected to the input terminal connector 31 of the indoor unit 30 via the above-mentioned coaxial cable 20.

Next, a more detailed configuration of the indoor unit 30 will be described. The input terminal connector 31 is connected to the input terminal of the tuner 32. This tuner 32 has a local oscillator and a microphone inside, and generates a second intermediate frequency,
This allows you to tune into your desired channel. tuner 3
The output of 2 is given to a bandpass filter 33 and is limited to a predetermined bandwidth. The output of the bandpass filter 33 is given to a second IF amplifier 34 and a second IF amplifier 35. The output of the 21st F amplifier 34 is given to a limiter '36 and an AGC detection circuit 37.

The output of the AGC detection circuit 37 is given to an AGC amplifier 38, where it is DC amplified. The output of the AGO amplifier 38 is the second.
It is applied to the gain control terminal of the 1F amplifier 34. That is, a feedback loop is formed by the AGC detection circuit 37 and the AGO amplifier 38, and the level of the output of the second IF amplifier 34 remains constant regardless of the strength of the electric field of the radio waves from the satellite. The limiter 36 limits the amplitude of the output of the 21st F amplifier 34. The output of this limiter 36 is given to an FM demodulator 46, where it is FM demodulated. FM demodulator 46
The video signal demodulated by is given to the RF converter 47. This RF converter 47 is for converting a video signal into a high frequency video signal of an empty channel of television broadcasting.

The output of this RF converter is given to a general home television receiver 50 via a coaxial cable 48.

On the other hand, the output of the second IF amplifier 35 is applied to a detector 39 and detected. The output of this detector 39 is given to a DC amplifier 40 and amplified. The output of DC amplifier 40 is given to a control terminal of voltage controlled attenuator 49. The output of the low frequency oscillator 41 is applied to the input terminal of this voltage controlled attenuator 49 . The oscillation frequency of this low frequency oscillator 41 is, for example, several kilohertz. The voltage controlled attenuator 49 is
The amplitude of the oscillation output of the low frequency oscillator is controlled according to the output level of the DC amplifier 40. The output of the voltage controlled attenuator 49, that is, the output of the low frequency oscillator 41 whose amplitude is controlled, is the RF
It is applied to the input terminal connector 31 via the choke coil 42.

Each circuit of the indoor unit 30 described above is driven by a voltage given from a power supply circuit 43.

The output of this power supply circuit 43 is further applied to the input terminal connector 31 via an LF (low frequency) choke coil 44 and an RF choke coil 45 .

That is, in addition to the high frequency signal transmitted from the outdoor unit 2 to the indoor unit 30, the direct current and low frequency signal transmitted from the indoor unit 30 to the outdoor unit 2 are superimposed on the coaxial cable 20.

Note that processing of audio signals in the drawings is omitted because it is not directly related to understanding the present invention. Such audio signal processing is well known in the art, and those skilled in the art can easily add or add an audio signal processing circuit to the illustrated embodiment.

Next, the operation will be explained. Note that since the basic receiving operation is the same as that of conventional receivers, the operations that are particularly interesting to the present invention will be described below.

First, the operation when the reception level of the reception anti-thick 1 is low will be explained. In this case, the output level of the 21F amplifier 35 in the indoor unit 30 also becomes low. Therefore, the detected output of the wave detector 39 and therefore the output voltage of the DC amplifier 40 also becomes low level. Accordingly, the voltage controlled attenuator 49
Therefore, the attenuation opening of the low frequency signal of the low frequency oscillator 41 becomes larger.

Therefore, the amplitude of the low frequency signal output from the voltage controlled attenuator 49 becomes small. The output of this voltage controlled attenuator 49 is the RF choke coil 42. Input terminal connector 31
．． Coaxial cable 20. Output terminal connector 8. The signal is applied to the test terminal 13 via the RF choke coil 10.15 and the DC blocking capacitor 12. Therefore, by measuring the level of the low frequency signal led out to the terminals 13 with an AC voltmeter, the level of reception at that time can be measured. Note that the R choke coil 10 prevents the high frequency signal output from the band pass filter 7 from flowing into the test terminal 13.
The DC blocking capacitor 12 blocks the DC voltage applied from the power supply circuit 43 of the indoor unit 30. That is, the RF choke coil 10 and the DC blocking capacitor 12 constitute means for separating low frequency signals.

Due to this means, only the low frequency signal transmitted from the indoor unit 30 is derived to the test terminal 13. Further, the RF choke coil 14 transmits the high frequency signal output from the band pass filter 7 to the low pass filter 9.
I try not to let it flow. Therefore, the low-pass filter 9 is selected to have a frequency characteristic that is roughly lower than the frequency of the low-frequency signal transmitted from the indoor unit 30, and blocks such low-frequency signals and controls only the DC voltage. It is applied to the circuit 11. On the other hand, the R choke coil 42 prevents the high frequency signal transmitted from the I outside unit 2 from flowing into the voltage controlled attenuator 49.

Similarly, the RF choke coil 45 prevents such high frequency signals from flowing into the power supply circuit 43. Furthermore, the LF choke coil 44 has a voltage controlled attenuator 49
The low frequency signals output from the power supply circuit 43 are prevented from flowing into the power supply circuit 43.

Next, the operation when the receiving level of the receiving antenna 1 is high will be explained. In this case, the situation is opposite to the above operation, and the amplitude of the low frequency signal transmitted from the indoor unit 30 to the outdoor unit 2 increases. Therefore, the amplitude of the low frequency signal derived to the test terminal 13 becomes large, and this can be detected using an AC voltmeter or the like.

As described above, a low frequency signal whose amplitude changes depending on the reception level of the radio wave is derived from the test terminal 13. Therefore, by measuring the amplitude of the low frequency signal derived to this test terminal 13, the receiving antenna 1
It is possible to know the reception level, that is, the electric field strength of the received radio waves. Therefore, by adjusting the direction of the receiving antenna 1 so that the indicated value of this AC voltmeter becomes maximum, the receiving antenna 1 can be accurately installed in the direction in which the radio waves arrive.

In the above-described embodiment, the 21F amplifier 35, the detector 39, and the DC amplifier 40 are provided, but these are omitted and the output of the illustrated AGCjlJ width amplifier 38 is directly connected to the voltage side @attenuator 49. It may also be applied to a control terminal. That is, the indoor unit 30 may be provided with means that can detect the reception level of radio waves based on the high frequency signal given from the outdoor unit 2.

Further, in the above-described embodiment, the receiver mainly receives broadcast radio waves from a satellite, but it is of course possible to use a receiver that receives radio waves transmitted from a communication satellite.

As described above, according to the present invention, by connecting a simple meter to the test terminal provided on the outdoor cornice, it is possible to know the field strength of the radio waves received by the receiving antenna and the receiving antenna. The direction can be adjusted accurately and easily. Furthermore, since the test terminal is provided in the outdoor unit, one person can adjust the receiving antenna while looking at the readings on the meter connected to the test terminal.

Therefore, the labor required for adjustment work can be reduced and the adjustment work can be performed quickly. Furthermore, since the outdoor unit and the indoor unit are connected by one transmission line, the device can be made inexpensive and the wiring work can be made easy.

[Brief explanation of the drawing]

The drawing is a schematic block diagram showing one embodiment of the present invention. In the figure, 1 is the receiving antenna, 2 is the outdoor unit, 1
3 is a test terminal, 10, 14, 42 and 45 are RF
A choke coil, 12 a DC blocking capacitor, 20 a coaxial cable, 30 an indoor unit, 32 a tuner,
34 and 35 are 21F amplifiers, 46 is an FM demodulator,
3 is a wave detector, 40 is a DC amplifier, 41 is a low frequency oscillator, 43 is a power supply circuit, 44 is an LF choke coil, 49 is a voltage controlled attenuator, and 50 is a television receiver.

Claims (4)

[Claims] (1) An antenna, an outdoor unit that includes at least a means for high-frequency amplification of radio waves received by the antenna, and an outdoor unit that is connected to the outdoor unit through one transmission line, and that receives radio waves from the outdoor unit via the transmission line. In a satellite receiver for receiving radio waves from a satellite, the indoor unit includes at least a demodulating means for demodulating received output, and the indoor unit adjusts the reception level of the radio waves based on the received output of the outdoor unit. and a reception level transmitting means for transmitting the output of the reception level detection means to the outdoor unit via the transmission line, the outdoor unit is provided with the output via the transmission line. A satellite receiver comprising a test terminal for outputting the output of the reception level detection means to the outside. (2) The reception level detection means includes: a detection means for detecting the reception output given from the outdoor unit; an oscillation circuit; and based on the output of the detection circuit, controls the amplitude of the oscillation output of the oscillation circuit. A satellite receiver according to claim 1, further comprising amplitude control means. (3) The satellite device according to claim 1 or 2, wherein the indoor unit includes: a power source; and means for sending the output of the power source to the outdoor unit via the transmission line. Receiving machine. (4) The satellite according to any one of claims 1 to 3, wherein the outdoor unit includes means for separating the output of the reception level detection means from the transmission line and applying it to the test terminal. receiver.