JP2800545B2 - Transmission frequency control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a transmission frequency control device of a satellite earth station. In particular, the present invention relates to a transmission frequency control device of a satellite communication earth station when three or more satellite communication earth stations use a request assignment satellite communication system in which two or more transmission paths are shared for communication.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of a conventional transmission frequency control device. FIG. 4 is a block diagram of a common signal demodulator, a communication signal demodulator, and a communication signal modulator of a conventional transmission frequency control device.

Generally, in a request assignment satellite communication system in which three or more satellite communication earth stations communicate by sharing two or more transmission paths, a common transmission path resource is managed and a transmission path is allocated according to a request. A common signal transmission line for transmitting a connection request and transmission line assignment information between the control station to be assigned and each earth station is required. When using the request assignment satellite communication system, each earth station normally receives a common signal sent from a control station, and when a communication request is received from a communication terminal device, a connection request is made using the common signal. And the control station is assigned a communication signal frequency, and the communication signal device receives the communication signal.

The common signal sent from the control station to each earth station is generally a continuous signal and a control signal before communication is performed. Therefore, the time required for each earth station to capture the common signal is very short. Although not a problem, the time for capturing the communication signal must be short in order to effectively use the satellite link.

However, since the frequency deviation caused by the satellite is common to all the stations, it is necessary to reduce the variation in the frequency deviation between the earth stations in order to shorten the acquisition time of the communication signal. The control for reception must take into account the frequency deviation due to the satellite and the frequency deviation between each earth station.

Conventionally, a transmission frequency control device has a configuration as shown in FIGS.

[0007] In FIGS. 3 and 4, a common signal transmitted from a control station via a satellite is usually referred to as an antenna 1.
The signal is received by the common signal demodulator 5C through the low noise amplifier 2, the reception frequency converter 3, and the distributor 4. In the common signal demodulator 5C, the frequency of the frequency synthesizer 52A is set so that the signal sent from the distributor 4 becomes the reception frequency of the common signal under the control of the common signal processing device 6C, and the synthesizer 53A, the demodulator 54A and Voltage controlled crystal oscillator 55
A demodulates the common signal including the frequency deviation due to the satellite, and passes the common signal data processed by the data processing unit 57A to the common signal processing device 6C.

When a communication request is received from the communication signal terminal device 11, the common signal processing device 6C sends the communication request to the common signal modulator 7, the distributor 8, the transmission frequency converter 9, the high power amplifier 10, and the like.
The control signal is sent to the control station via the antenna 1 and the communication signal is controlled by controlling the communication signal modulator 12C and the communication signal demodulator 13C so that the communication frequency is designated by the common signal from the control station.

[0009]

However, such a conventional transmission frequency control apparatus receives a continuous signal because no measures have been taken to reduce the frequency deviation between the satellite communication earth stations. Even in this case, if the frequency deviation between the satellite communication earth stations is large, there is a problem that it takes time to acquire the frequency, and when receiving the discontinuous signal, the variation in the frequency deviation between the satellite communication earth stations is reduced. When the frequency is large, it takes a long time to acquire the frequency, so that the signal cannot be received, and there is a problem that the satellite line cannot be used effectively.

The present invention solves the above problems,
It is an object of the present invention to provide a transmission frequency control device capable of shortening the acquisition time of a satellite communication signal and improving the utilization efficiency of a satellite link.

[0011]

According to the present invention, a transmitting means and a receiving means for performing communication by sharing a plurality of transmission paths, and a common signal from a control station based on an input first control signal are transmitted to the receiving means. A common signal demodulator that receives and demodulates the signal via a common signal demodulator, a processing unit that outputs the first control signal based on an output signal of the common signal demodulator, and a communication signal from a partner station based on the input second control signal. At least three satellite communication earth stations including a communication signal demodulator for receiving and demodulating via a receiving means, and a communication signal modulator for modulating a communication signal based on an input third control signal and transmitting via a transmitting means. In the transmission frequency control device provided with, the common signal demodulator and the communication signal demodulator each include a frequency detection unit that detects a frequency deviation of the received signal, the common signal demodulator has detected A logic unit including means for estimating a frequency deviation due to the satellite based on the wave number deviation and means for estimating a frequency deviation of the other station based on the frequency deviation detected by the communication signal demodulator; A means for outputting the second control signal based on the deviation and a means for providing the third control signal to the partner station based on the frequency deviation of the partner station are provided.

In the present invention, the means to be provided to the partner station may include a means for supplying the communication signal modulating means of the partner station via the processing means and the logic device of the partner station.

[0013]

The common signal demodulator and the communication signal demodulator detect the frequency deviation of the received signal by the frequency detector. The logic unit estimates the frequency deviation due to the satellite based on the frequency deviation detected by the common signal demodulator, and estimates the frequency deviation of the partner station based on the frequency deviation detected by the communication signal demodulator. The processing means outputs a second control signal to the communication signal demodulator based on the frequency deviation of the satellite, and provides a third control signal to the partner station based on the frequency deviation of the partner station.

As described above, the satellite communication signal acquisition time can be shortened, and the utilization efficiency of the satellite link can be improved.

[0015]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a transmission frequency control device according to an embodiment of the present invention. FIG. 2 is a block diagram of a common signal demodulator, a communication signal demodulator, and a communication signal modulator of the transmission frequency control device according to the present invention.

In FIG. 1, a transmission frequency control device includes a synthesizer 8, a transmission frequency converter 9, a high power amplifier 10, a part of an antenna 1, and a receiving means as transmitting means for performing communication by sharing a plurality of transmission paths. A part of the antenna 1, the low noise amplifier 2, the reception frequency converter 3 and the distributor 4, and a common signal from the control station based on the reception frequency control signal 103 as the first control signal to be input is received via the reception means. A common signal demodulator 5 for receiving and demodulating, a common signal processing device 6 as processing means for outputting a reception frequency control signal 103 based on an output signal of the common signal demodulator 5, and a reception frequency control signal 104 as a second control signal to be input. A communication signal demodulator 13 for receiving and demodulating a communication signal from a partner station via the receiving means based on the It comprises three stations or more satellite earth station including modulating the communication signal based on a control signal 102 the communication signal modulator 12 for transmission via the transmission means. Also,
The satellite communication earth station includes a common signal modulator 7 that modulates a common signal based on a transmission frequency control signal 101 from the common signal processing device 6 and transmits the modulated signal via the transmission unit, and a communication signal terminal device 11.

Here, a feature of the present invention is that the common signal demodulator 5 and the communication signal demodulator 13 each include a frequency detector 56A for detecting a frequency deviation of the received signal.
56B, means for estimating the frequency deviation due to the satellite based on the frequency deviation measurement signal 201 as the frequency deviation detected by the common signal demodulator 5 and the partner based on the frequency deviation measurement signal 202 as the frequency deviation detected by the communication signal demodulator 13 Logic 1 including means for estimating the frequency deviation of the station
A common signal processing device 6 for outputting a reception frequency control signal 103 based on the frequency deviation of the satellite, and a transmission frequency deviation control signal 203 (frequency deviation notification signal 200) based on the frequency deviation of the other station. To the communication signal modulator 12 via the common signal processing device 6 and the logic device 14 of the partner station.

The common signal demodulator 5 includes a synthesizer 51A.
And a frequency synthesizer 52A for inputting the transmission frequency control signal 102, a synthesizer 53A, a demodulator 54A, a data processing unit 57A, and a voltage controlled crystal oscillator 55A.

Further, the communication signal demodulator 13 includes the synthesizer 5
1B, a frequency synthesizer 52B for inputting the transmission frequency control signal 104, a synthesizer 53B, and a demodulator 54B
, A data processing unit 57B, and a voltage-controlled crystal oscillator 55
B.

The communication signal modulator 12 includes a data processor 31, a modulator 32, a synthesizer 33, and a frequency synthesizer 34 for inputting a transmission frequency deviation control signal 203.
, A synthesizer 35, and a frequency synthesizer 36 for inputting the reception frequency control signal 103.

The operation of the transmission frequency control device having such a configuration will be described. 1 and 2, the common signal demodulator 5 detects the frequency deviation due to the satellite by the frequency detecting unit 56.
A, the frequency deviation measurement signal 201 is
Pass to.

Next, in the frequency synthesizer 52B of the communication signal demodulator 13, the logic device 14 estimates the frequency deviation due to the satellite from the frequency deviation measurement signal 201 in advance, and corrects it with the reception frequency control signal 104. That is, assuming that there is no transmission frequency deviation of the control station and no reception frequency deviation of the own station, control is performed on the assumption that all are frequency deviations due to satellites.

After receiving the communication signal, the frequency deviation detected by the frequency detector 56B of the communication signal demodulator 13 can be estimated to be only the frequency deviation of the communication partner station. The transmission station controls the frequency synthesizer 34 of the communication signal modulator 12 with this signal so that the transmission frequency deviation becomes the same as that of the control station.

[0024]

As described above, the present invention has an excellent effect that the acquisition time of a satellite communication signal can be shortened and the utilization efficiency of a satellite link can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a transmission frequency control device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a common signal demodulator, a communication signal demodulator, and a communication signal modulator of the transmission frequency control device according to the present invention.

FIG. 3 is a block diagram of a conventional transmission frequency control device.

FIG. 4 is a block diagram of a common signal demodulator, a communication signal demodulator, and a communication signal modulator of a conventional transmission frequency control device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 antenna 2 low noise amplifier 3 reception frequency converter 4 distributor 5, 5C common signal demodulator 6, 6C common signal processing device 7 common signal modulator 8, 33, 35, 51A, 51B, 53A, 53B synthesizer 9 transmission Frequency converter 10 High power amplifier 11 Terminal device for communication signal 12, 12C Communication signal modulator 13, 13C Communication signal demodulator 14 Logic device 31, 57A, 57B Data processing unit 32 Modulation unit 34, 36, 52A, 52B Frequency synthesizer 54A, 54B Demodulator 55A, 55B Voltage controlled crystal oscillator 56A, 56B Frequency detector 101, 102 Transmit frequency control signal 103, 104 Receive frequency control signal 200 Frequency deviation communication signal 201, 202 Frequency deviation measurement signal 203 Transmission frequency deviation control signal

Claims (2)

(57) [Claims] 1. A transmitting means and a receiving means for performing communication by sharing a plurality of transmission paths, and a demodulator for receiving and demodulating a common signal from a control station via said receiving means based on an input first control signal. Processing means for outputting the first control signal based on the output signal of the common signal demodulator; communication for receiving and demodulating a communication signal from a partner station via the receiving means based on the input second control signal A transmission frequency control apparatus comprising three or more satellite communication earth stations including a signal demodulator and a communication signal modulator for modulating a communication signal based on an input third control signal and transmitting the modulated signal via the transmission means, Each of the common signal demodulator and the communication signal demodulator includes a frequency detection unit for detecting a frequency deviation of the received signal, and a frequency of a satellite based on the frequency deviation detected by the common signal demodulator. A logic unit including a means for estimating the deviation and a means for estimating the frequency deviation of the other station based on the frequency deviation detected by the communication signal demodulator, wherein the processing means comprises: A transmission frequency control device, comprising: means for outputting a control signal; and means for providing the third control signal to the partner station based on the frequency deviation of the partner station. 2. The transmission frequency control device according to claim 1, wherein the means for providing to the partner station includes means for supplying the communication signal modulator of the partner station via processing means and a logic device of the partner station.