JPH05336012A - Satellite-mounted repeater - Google Patents

Abstract

PURPOSE:To make a frequency highly stable while keeping communication by making the local oscillator of a frequency converter and a beacon oscillator synchronize with a common reference oscillator and providing a frequency adjusting function on the reference oscillator. CONSTITUTION:This satellite-mounted repeater generates a local oscillating frequency used for frequency converters 6-1-6-n converting the frequency into an up-link frequency and a down-link frequency and the beacon frequency of the beacon oscillator 8 by using a common original frequency generated from a reference oscillator 9 whose oscillating frequency is variable. Thus, the frequency stability of the satellite-mounted repeater depends only on the frequency stability of the reference oscillator 9. When the frequency of the reference oscillator is fluctuated, the high stability of the frequency of the satellite-mounted repeater is realized by adjusting the frequency of the reference oscillator so as to eliminate the fluctuation. Furthermore, the frequency is adjusted while keeping the communication.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite-mounted repeater, and more particularly to a satellite-mounted repeater having high frequency stability.

[0002]

2. Description of the Related Art FIG. 4 shows an example of the configuration of a main part of a conventional satellite-mounted repeater related to beacons and frequency conversion.
In this figure, 1 _-1 to 1 _{-n + 1} are reference oscillators, 6 _{-1 to} 6
_-n is a frequency converter, 2 _-1 to 2 _-n is a local oscillation system of the frequency converter, 3 _{-1 to} 3 _-n is a mixer of the frequency converter, 4 _-1 to 4 _-n
Is an RF input unit of the frequency converter, 5 _{-1 to} 5- _n is an RF output unit of the frequency converter, 7 is a beacon frequency generation system, and 8 is a beacon oscillator.

Conventionally, this kind of satellite-mounted repeater with a small frequency fluctuation has an original oscillation frequency by an individual reference oscillator 1 _-1 to 1 _-n such as a crystal oscillator having a very high frequency stability as shown in FIG. supplying, by a local oscillation system 2 _-1 to 2 _-n, it was adopted a structure that generates a local oscillation frequency used in the frequency converter 6 _-1 to 6 _-n for converting the uplink frequency to the downlink frequency .. The beacon oscillator 8 also has a configuration in which the beacon frequency is generated from the original oscillation frequency by the independent reference oscillator 1 _{-n +1} .

[0004]

Since the conventional satellite-mounted repeater with a small frequency fluctuation is constructed as described above, the frequency stability is determined by an individual reference such as a crystal oscillator for supplying the original oscillation frequency of the local oscillation system. It depended on the frequency stability of the oscillators 1 _-1 to 1 _-n . For this reason, the frequencies of a plurality of frequency converters vary independently, that there is no function to adjust when the original oscillator frequency of each reference oscillator changes, and to detect frequency fluctuations. Has to input an unmodulated signal into a satellite repeater and measure the frequency of its output unmodulated signal, which has the drawback that communication services must be interrupted to measure frequency fluctuations. It was

The present invention has been made to solve the above-mentioned drawbacks, and by adding a frequency adjusting function, the frequency can be obtained without depending on the performance of the reference oscillator that supplies the original oscillation frequency of the local oscillation system. It is an object of the present invention to realize a satellite-mounted repeater with high stability and to realize a satellite-mounted repeater capable of detecting frequency fluctuations and adjusting frequencies while continuing communication.

[0006]

FIG. 1 shows the principle structure of the present invention.
FIG. 3 is a diagram showing the configuration of the satellite repeater beacon and
The structure of the main part regarding frequency conversion is shown. this
In the figure, 6_-1~ 6 _-nIs a frequency converter, 2_-1~ 2_-nIs
Local oscillation system of frequency converter, 3_-1~ 3_-nIs a frequency converter
Mixer, 4_-1~ 4_-nIs the RF input part of the frequency converter,
5_-1~ 5_-nIs the RF output of the frequency converter, and 7 is Beco
Frequency generation system, 8 is a beacon oscillator, 9 is variable frequency
Reference oscillator, 13 is a frequency control means of the reference oscillator.
I forgot.

As shown in FIG. 1, the satellite-mounted repeater of the present invention is used for frequency converters 6 _{-1 to} 6 _-n for converting an uplink frequency into a downlink frequency, a beacon oscillator 8 and the frequency converter. A frequency-variable reference oscillator 9 is provided which supplies a local oscillation frequency and a common source frequency for generating the beacon frequency of the beacon oscillator. The original oscillation frequency of the reference oscillator is a frequency required to generate the greatest common divisor of the local oscillation frequency and the beacon frequency of each of the frequency converters 6 _{-1 to} 6 _-n .

[0008]

The satellite-mounted repeater of the present invention uses the local oscillator frequency and the beacon frequency of the beacon oscillator 8 used in the frequency converters 6 _{-1 to} 6 _-n for converting the uplink frequency into the downlink frequency in FIG. Variable frequency reference oscillator 9
It is generated using a common source frequency supplied from.

Therefore, the frequency stability of the satellite repeater of the present invention depends only on the frequency stability of the reference oscillator 9. Since the reference oscillator 9 has a variable frequency, when the frequency of the satellite-mounted repeater fluctuates, the frequency of the satellite-mounted repeater can be highly stabilized by adjusting the frequency of the reference oscillator so that the fluctuation does not occur. .. In addition, the state of frequency fluctuations can be monitored by measuring the frequency of the beacon, which is an unmodulated signal, so there is no need to stop communication to detect changes in frequency, and the frequency can be adjusted while communication is continued. Is.

There are the following methods for controlling the frequency of the reference oscillator. The frequency fluctuation is monitored by measuring the frequency of the beacon, which is an unmodulated signal. The means for detecting the deviation of the beacon frequency detects the deviation of the beacon frequency from the specified frequency, and the control means for controlling the oscillation frequency of the reference oscillator controls the oscillation frequency of the reference oscillator so as to eliminate the deviation. It is also possible to configure the control system so that the beacon frequency is measured on the ground, the deviation from the specified frequency is detected, and the oscillation frequency of the reference oscillator is controlled from the ground by a command so that the deviation disappears. is there.

The variable frequency reference oscillator 9 can be constructed by using a voltage controlled oscillator (VCO), a voltage controlled crystal oscillator (VCXO) or the like. In that case, in order to control the oscillation frequency, only the voltage is controlled. Good.

In the case of a configuration in which the uplink frequency is converted into the downlink frequency by using a plurality of frequency converters, the local oscillation frequency used for each frequency converter is a common source supplied from the reference oscillator. A similar effect can be obtained by generating using the vibration frequency.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.
It FIG. 2 shows an embodiment of the present invention.
Single beam, single beam satellite
It is an example of a structure of a repeater, and is 2_-1Is the local oscillation system, 3 _-1Is
Mixer, 4_-1Is the RF input section, 5_-1Is the RF output section, 6
_-1Is a frequency converter, 7 is a beacon frequency generation system, and 8 is a
Control oscillator, 9 is a variable frequency reference oscillator, and 10 is low
Noise amplifier (LNA), 11 is a power amplifier (HPA),
Reference numeral 12 represents a beacon transmitter.

The frequency converter 6 _{-1 is used} to convert the uplink frequency into the downlink frequency. Low noise amplifier (LNA) for receiving and amplifying weak uplink signal with low noise, and power amplifier (HPA) for obtaining required output of downlink signal
Are connected before and after the frequency converter 6 _-1 , and the beacon transmitter 8 for obtaining the required output of the beacon is the beacon oscillator 7
The satellite-mounted repeater is connected to the latter stage.

FIG. 3 shows another embodiment of the present invention, which is an example of the configuration of a single-beam, double-conversion satellite-mounted repeater. The present embodiment shows a case where the frequency converter 6 _-1 and the frequency converter 6 _-2 convert the uplink frequency to the downlink frequency.

The reference numerals in the figure are the same as those in FIG.

In any of the configurations shown in FIG. 2 and FIG. 3, the frequency stability of the satellite-mounted repeater is the frequency of the frequency-variable reference oscillator 9 as described in the above "Operation" section. By measuring the frequency of the beacon, which is an unmodulated wave, which depends only on the stability, it is possible to monitor the frequency fluctuations of the satellite-mounted repeater while continuing communication. Then, the deviation of the beacon frequency is detected, and the oscillation frequency of the reference oscillator is adjusted so as to eliminate the deviation, whereby the frequency of the repeater mounted on the satellite can be highly stabilized.

A multi-beam type satellite-mounted repeater,
In a satellite-mounted repeater of any configuration, such as a satellite-mounted repeater equipped with multiple missions with different frequency bands,
Similar effects can be obtained by adopting a configuration in which the original oscillation frequencies of all frequency converters and all beacon oscillators are supplied from a common reference oscillator.

[0019]

As described above, the satellite-mounted repeater of the present invention synchronizes the local oscillator and the beacon oscillator of the frequency converter with a common reference oscillator, and adds a frequency adjusting function to the reference oscillator. Therefore, it is possible to easily realize a satellite-mounted repeater with high frequency stability.
There is an advantage that high frequency stabilization can be realized while continuing communication.

[Brief description of drawings]

FIG. 1 is a diagram showing a principle configuration of the present invention.

FIG. 2 is a diagram showing an embodiment of the present invention.

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is a diagram showing an example of a configuration of a main part of a conventional satellite repeater.

[Explanation of symbols]

1, 1 _-1 to 1 _{-n + 1} Reference oscillator 2 _-1 to 2 _-n Local oscillator system of frequency converter 3 _{-1 to} 3 _-n Mixer of frequency converter 4 _-1 to 4 _-n Frequency converter RF system input section 5 _{-1 to} 5 _-n RF converter output section of frequency converter 6 _{-1 to} 6 _-n frequency converter 7 Beacon frequency generation system 8 Beacon oscillator 9 Frequency variable reference oscillator 10 Low noise amplifier (LNA) 11 Power Amplifier (HPA) 12 Beacon Transmitter 13 Reference Oscillator Frequency Control Means

Claims (1)

[Claims] 1. A satellite transponder having frequency conversion means for converting an uplink frequency into a downlink frequency and beacon oscillating means, wherein an oscillation frequency of a local oscillator of the frequency converting means and an oscillation of the beacon oscillating means. A satellite-borne repeater, comprising means for determining a frequency on the basis of an oscillation frequency of one reference oscillator and arbitrarily changing the oscillation frequency of the one reference oscillator.