KR0140677B1 - Satellite broadcasting repeater - Google Patents

Abstract

The present invention relates to a repeater for satellite broadcasting, and further comprising a phase control unit (200) for simultaneously controlling phases of the first local oscillator (30) and the second local oscillator (70) used in the satellite broadcasting repeater. By stabilizing the oscillation signals of the oscillator 30 and the second local oscillator 70, it is possible to transmit broadcast radio waves fixed at 12 kHz to the ground.

Description

Phase Control Circuit of Satellite Broadcasting Repeater

1 is a schematic configuration diagram of a repeater for satellite broadcasting according to the present invention;

2 is a schematic configuration diagram of a conventional satellite broadcasting repeater.

* Explanation of symbols for the main parts of the drawings

10: receiving antenna 20: low noise amplifier

25: first bandpass filter 30: first local oscillator

40: first mixer 50: second bandpass filter

60: narrowband amplifier 70: second local oscillator

80: second mixer 90: third bandpass filter

100: high power amplifier 110: transmission antenna

200: phase control unit 210: first divider

220: reference oscillator 230: first phase detector

240: second low pass filter 250: second divider

The present invention relates to a repeater for satellite broadcasting, and in particular, it is possible to simultaneously control the phase of the oscillation signal of the first local oscillator and the second local oscillator used in the satellite broadcast repeater oscillation of the first local oscillator and the second local oscillator A phase control circuit of a satellite broadcasting repeater capable of stabilizing a signal.

In general, a satellite broadcast repeater refers to a repeater system having a so-called reception and transmission function that receives a broadcast wave sent from an earth station and transmits it to the ground again.

The satellite broadcasting repeater is composed of one or more transponders, and the transponders are a transmitting / receiving device that receives an uplink signal transmitted from an earth station and amplifies it in a low noise amplifier (LNA). In this case, a high-power amplification is performed at a high frequency power amplifier, and then transmitted to an earth station through a transmitting antenna.

The transponder can be classified into two types according to the signal processing method and the frequency conversion frequency. In the signal processing method, there are a general transponder which converts a received signal into a downlink frequency and transmits the signal, and a reproducing transponder that detects the received signal, converts the received signal into a baseband signal, processes it, and modulates it.

In addition, the single frequency conversion type transponder converts the received frequency directly to the downlink frequency according to the frequency conversion frequency and the dual frequency conversion type converts the received frequency into an intermediate frequency and then amplifies and converts the downlink frequency. There is a transponder.

As such, the reason for converting the uplink frequency to the downlink frequency in the satellite broadcasting repeater is to isolate the transmit / receive frequency to avoid interference between the transmit / receive signals, and to convert the uplink frequency into the intermediate frequency in the dual frequency conversion transponder. The conversion to a signal and then to downlink frequency is to obtain sufficient gain that is difficult to obtain as a single conversion. In addition, since it is difficult to switch the high frequency when the signal is to be switched from the satellite, a double conversion transponder is used to convert the high frequency into the intermediate frequency.

The conventional satellite broadcast repeater described above includes a reception antenna 10 for receiving 14k broadcast signals transmitted from a ground station, as shown in FIG. A low noise amplifier (LNA: 20) for minimizing and amplifying the noise figure of the broadcast signal received through the antenna 10; A first band pass filter (BPF) 25 which removes and outputs frequency noise of the broadcast signal output from the low noise amplifier 20; A first local oscillator (1stL. 0:30) for outputting an oscillation frequency of 13 kHz; A first mixer (40) for mixing the 14 kHz broadcast signal frequency and the 13 kHz oscillation frequency output from the first band pass filter (25); A second band pass filter (BPF) 50 for extracting frequencies of 1 kHz among frequencies output from the first mixer 40; A narrow band amplifier (Amp: 60) for amplifying 1 kHz broadcast signals output from the second band pass filter (50); A second local oscillator (2nd L.0: 70) for outputting an oscillation frequency of 11 GHz; A second mixer (80) for mixing the amplified 1 kHz broadcast signal and the 11 kHz frequency; A third band pass filter (BPF) 90 for extracting 12 kHz downlink frequencies from the frequencies output from the second mixer 80; A high power amplifier (HPA) 100 for high power amplifying the downlink frequency broadcast signal output from the third band pass filter 90; And a transmission antenna 110 for transmitting the high power amplified broadcast signal toward the ground.

In the conventional satellite broadcasting repeater configured as described above, when 14 ㎓ broadcast signals transmitted from a ground station are received by the reception antenna 10, the low noise amplifier 20 minimizes the noise figure of the broadcast signal received through the antenna 10. Amplified and outputted, the broadcast signal output from the low noise amplifier 20 is output by removing the frequency noise from the first band pass filter 25, the first local oscillator 30 in the first mixer (40) 27 Hz and 1 Hz frequency signals are mixed with the 13 Hz oscillation frequency, and only 1 Hz frequency signal is detected by the second band pass filter 50.

The frequency signal of 1 kHz is mixed again in the second mixer 80 with the 11 kHz oscillation frequency output from the second local oscillator 70 and then as the 12 kHz frequency signal in the third band pass filter 90. Is output. The 12 kHz frequency signal is a high power amplified by the high power amplifier 100 is transmitted to the ground through the transmission antenna 110.

However, in the conventional satellite broadcasting repeater, the first local oscillator 30 and the second local oscillator 70 are separately used as described above, so that the phase difference between the local oscillators 30 and 70 is generated and the phase noise is generated. There was a problem that noise occurs.

Accordingly, the present invention has been proposed to solve the above problems of the prior art, and the phases of the first local oscillator and the second local oscillator used in the satellite broadcasting repeater can be controlled according to the same reference signal. It is an object of the present invention to provide a phase control circuit of a satellite broadcasting repeater capable of stabilizing an oscillation signal.

In order to achieve the above object, a phase control circuit of a satellite broadcasting repeater according to the present invention includes a first local oscillator which oscillates a predetermined frequency to obtain an intermediate frequency signal from a received high frequency signal, and converts the intermediate frequency signal into a transmission high frequency signal. A repeater for satellite broadcasting comprising a second local oscillator for oscillating a predetermined different frequency, comprising: a first divider for dividing an output signal of the first local oscillator; A second divider for dividing an output signal of the second local oscillator; A reference oscillator for oscillating a predetermined reference frequency signal; A first phase detector for comparing a phase of the signal divided by the first divider with a signal generated by the reference oscillator and detecting a phase difference thereof; A first low pass filter for filtering the phase difference output from the first phase detector and providing the first local oscillator at a DC level; A second phase detector for comparing the phases of the signal divided by the second divider with the signal generated by the reference oscillator and detecting a phase difference thereof; And a second low pass filter for filtering the phase difference output from the second phase detector to provide the second local oscillator at a DC level.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic configuration diagram of a satellite broadcasting repeater according to the present invention, comprising: a reception antenna 10 for receiving 14k broadcast signals transmitted from a ground station; A low noise amplifier (LNA: 20) for minimizing and amplifying the noise figure of the broadcast signal received through the antenna 10; A first band pass filter (BPF) 25 which removes and outputs frequency noise of the broadcast signal output from the low noise amplifier 20; A first local oscillator (1st L.0: 30) for outputting an oscillation frequency of 13 Hz; A first mixer (40) for mixing the 14 kHz broadcast signal frequency output from the first band pass filter (BPF) 25 and the 13 kHz oscillation frequency; A second band pass filter (BPF) 50 for extracting frequencies of 1 kHz among frequencies output from the first mixer 40; A narrow band amplifier (Amp: 60) for amplifying 1 kHz broadcast signals output from the second band pass filter (50); A second local oscillator (2nd L.0: 70) for outputting an oscillation frequency of 11 GHz; A second mixer (80) for mixing the amplified 1 kHz broadcast signal and the 11 kHz frequency; A third band pass filter (BPF) 90 for extracting 12 kHz downlink frequencies from the frequencies output from the second mixer 80; A high power amplifier (HPA) 100 for high power amplifying the broadcast signal of the downlink frequency output from the third band pass filter 90: a transmission antenna 110 for transmitting the high power amplified broadcast signal toward the ground; It comprises a phase control unit 200 for controlling the oscillation frequency and phase of the first local oscillator 30 and the second local oscillator 70 at the same time.

The phase controller 200 may include: a first divider 210 for dividing and outputting the oscillation frequency of the first local oscillator 30; A reference oscillator 220 for outputting a reference frequency; A first phase detector (230) for detecting a phase difference by comparing a phase of the frequency divided by the first divider (210) with a phase of the reference frequency output from the reference oscillator (220); A first low pass filter (L.P.F: 240) for filtering the phase difference output from the first phase detector 230 and providing the first local oscillator 30 at a DC level; A second divider 250 for dividing and outputting the oscillation frequency of the second local oscillator 70; A second phase detector (260) for outputting a phase difference by comparing the phase of the divided frequency output from the second divider (250) with the phase of the reference frequency output from the reference oscillator (220); And a second low pass filter (L.P.F: 270) for filtering the phase difference output from the second phase detector 260 and providing the second local oscillator 70 at a DC level.

Next, the action and effect according to the present invention configured as described above will be described in detail.

When the 14 kHz broadcast signal transmitted from the ground station is received by the reception antenna 10, the low noise amplifier 20 causes the antenna 20 to minimize the noise index of the broadcast signal received through the antenna 10 while the broadcast signal is received. Amplify the output. The broadcast signal output from the low noise amplifier 20 is removed with frequency noise by the first band pass filter 25 and mixed with 13 kHz oscillation frequency of the first local oscillator 30 in the first mixer 40. 27Hz and 1Hz frequency signals are output. The second band pass filter 50 outputs only one frequency signal at the output of the first mixer 40.

The 1 kHz frequency signal is mixed again by the 11 kHz oscillation frequency output from the second local oscillator 70 and the second mixer 80, and then only the 12 kHz frequency signal is transmitted by the third band pass filter 90. Is output. The 12 kHz frequency signal is high power amplified by the high power amplifier 100 and is transmitted to the ground through the transmission antenna 110.

In this case, the first local oscillator 30 and the second local oscillator 70 are simultaneously controlled by the phase control unit 200 so that the oscillation frequency and the phase are stabilized and the phase noise is removed. That is, the oscillation frequency of the first local oscillator 30 in the phase controller 200 is divided by the first divider 210 and then input to the first phase detector 230. The first phase detector 230 compares the phase of the divided frequency signal with the reference frequency output from the reference oscillator 220 and outputs the phase difference. The phase difference signal is filtered by the low pass filter 240 and fed back into the first local oscillator 30 as a signal corresponding to the phase difference between the oscillation frequency and the reference frequency, whereby the first local oscillator 30 oscillates. Frequency and phase can be kept constant.

On the other hand, the oscillation frequency of the second local oscillator 70 is divided into the second divider 250 and is input to the second phase detector 260, the second phase detector 260 in the reference oscillator 220 The phase difference is output after comparing with the output reference frequency. The phase difference signal is filtered by the low pass filter 270 and input to the second local oscillator 70 at a DC level. As a result, the second local oscillator 70 can maintain a constant oscillation frequency and phase. As described above, in the present invention, the phase difference between the oscillation frequencies output from the local oscillator can be removed by simultaneously controlling the phases of the local oscillators by the reference frequency output from one reference oscillator.

As described above, the present invention is capable of simultaneously controlling the phase of the first local oscillator and the second local oscillator in the satellite broadcast repeater, it is possible to stabilize the oscillation signal of the first local oscillator and the second local oscillator It has an effect.

Claims (1)

A first local oscillator 30 oscillating a predetermined frequency to obtain an intermediate frequency signal from an uplink received high frequency signal, and a predetermined other frequency for converting the intermediate frequency signal into a high frequency signal for transmitting the downlink In the satellite broadcasting repeater having a second local oscillator 70 to oscillate, A first divider 210 for dividing an oscillation signal of the first local oscillator 30; A second divider 250 for dividing the oscillation signal of the second local oscillator 70; One reference oscillator 220 for oscillating a predetermined reference frequency signal; A first phase detector 230 for comparing a phase of the divided signal output from the first divider 210 with a reference signal generated by the reference oscillator 220 and detecting a phase difference thereof; A first low pass filter 240 filtering the phase difference signal output from the first phase detector 230 and providing the first local oscillator 30 as a DC level; A second phase detector 260 which compares a phase of the divided signal output from the second divider 250 and a reference signal generated by the reference oscillator 9220 and detects a phase difference thereof; And And a second low pass filter 270 for filtering the phase difference signal output from the second phase detector 260 to the second local oscillator 70 at a DC level. Phase control circuit.