JPH03117037A - Transmitter/receiver for satellite communication - Google Patents

Abstract

PURPOSE:To sufficiently present function as the repeater of a communication satellite by detecting the signal level of an SCPC signal to be received from the communication satellite with a reception level detector, fed-backing it to a transmission level controller and respectively adjusting signal levels transmitted to the communication satellite in respective earth stations. CONSTITUTION:The subject equipment is constituted of a transmission/reception antenna 1, receiver 3, transmitter 4 and transmission/reception frequency divider 2 and is a transmitter/receiver for satellite communication to execute SCPC communication through the repeater of the communication satellite, a reception level detecting means 5 is provided on the receiver 3 to detect the reception signal level. Then, on the transmitter 4, a transmission level control means 6 is provided to control the transmission signal level corresponding to the reception signal level to be detected by the reception level detecting means 5. Thus, the transmission signal level can be automatically controlled so that the signal levels of the respective SCPC signals can be made equal on the communication satellite, and the repeater of the communication satellite can sufficiently present the original function.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides SCPC (Sin
The present invention relates to a transmitting/receiving device for satellite communication of an earth station that performs (QLE Channel Per Carrier) communication.

(Prior Art) Generally, a satellite communication transmitting/receiving device for an earth station that performs SCPC communication via a communication satellite includes a transmitting/receiving antenna, a transmitting/receiving duplexer, a receiver, and a transmitter. In conventional satellite communication transmitting/receiving devices, when SCPC communication is performed between each earth station using a communication satellite as a repeater, the signal level of the SCPC signal transmitted from the satellite communication transmitting/receiving device of each earth station to the communication satellite is Each was determined independently of the signal level of the received signal from the communication satellite in the earth station's satellite communication transmitter/receiver.

(Problem to be solved by the invention) A communication satellite repeater receives S signals sent from multiple earth stations.
The CPC signals are simultaneously amplified and the amplified SCPC signals are transmitted to each earth station. Amplifying a plurality of mutually different signals at the same time in this way with one amplifier is called simultaneous amplification. A transmitting amplifier that performs simultaneous amplification generates a third-order intermodulation product (IM). Here, if the signal levels of the SCPC signals sent from the earth station are not equal, the third-order intermodulation product (IM) generated from the SCPC signal with a high signal level will interfere with the SCPC signal with a low signal level. There is a thing. In order to reduce this interference, if the signal levels of the received SCPC signals are not equal, the amplification of the transmitting amplifier of the communications satellite repeater should be set to each receiving SCPC (signal level is equal) If the communication satellite repeater has a low
Since the reliable transmitter/receiver did not have a function to automatically control the transmitted signal level so that the signal levels of each S e P' and C signal on the communication satellite were equal, as mentioned above, There was an issue that needed to be resolved, which was that he was no longer able to fully demonstrate his abilities.

(Means for Solving the Problems) Means provided by the present invention to solve the above-mentioned problems are as follows:
a transmitting/receiving antenna directed toward a communication satellite; a receiver demodulating a signal received by the transmitting/receiving antenna; a transmitter generating a signal to be transmitted from the transmitting/receiving antenna; and connecting the transmitting/receiving antenna to the receiver and the transmitter. and a transmitting/receiving demultiplexer, and transmits the SCP via the communication satellite repeater.
A satellite communication transmitting and receiving device for an earth station that performs C communication,
The receiver is provided with a reception level detection means for detecting a reception signal level, and the transmitter is provided with a transmission level control means for controlling a transmission signal level according to the reception signal level detected by the reception level detection means. shall be.

(Example) Next, the present invention will be explained in detail with reference to Examples.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In this figure, 1 is a transmitting and receiving antenna, 2 is a transmitting and receiving duplexer,
3 is a receiver, 4 is a transmitter, 5 is a reception level detector, and 6 is a transmission level controller.

The SCPC signal sent from the communication satellite to the satellite communication transmitting/receiving device of this embodiment is received by the transmitting/receiving antenna 1 and sent to the receiver 3 by the transmitting/receiving duplexer 2 and received by the transmitting/receiving duplexer 2. sc sent from the transmitting/receiving device to the communication satellite,
The pc signal is transmitted from the transmitter 4 through the transmitter/receiver duplexer 2 and from the transmitter/receiver antenna 1. The transmitting/receiving duplexer 2 prevents the SC and PCC signals received by the transmitting/receiving antenna 1 from going around to the transmitter 4 and the SCPC signal transmitted from the transmitter 4 from going around to the receiver 3, respectively.

Since the signal level of the SCPC signal transmitted by the communication satellite to each earth station is the same for each earth station and the signal level is known, it is necessary to detect the signal level of the 5CPC signal received at each earth station. The transmission loss between the communication satellite and the earth station can be determined by Therefore, the SCPC transmitted from the earth station's satellite communication transceiver to the communication satellite
The received signal level of the signal at the communication satellite can be determined by subtracting the transmission loss between the communication satellite and the earth station from the transmission signal level of the satellite communication transmitter/receiver of the earth station. Therefore, each earth station detects the received signal level of the SCPC signal from the communication satellite using the satellite communication transmitting/receiving device, and controls the transmission signal level of the SCPC signal to be transmitted to the communication satellite based on the detected value. SCP on communication satellite
Since the received signal level of the C signal can be adjusted to a preset level, each 5CPC transmitted from each earth station
The signal levels received by the communication satellites can be made equal to each other. In this embodiment, the receiver 3 is provided with a reception level detector 5 to detect the signal level of the SCPC signal received from the communication satellite, and the signal level is fed back to the transmission level controller 6 provided in the transmitter 4 to detect the signal level of the SCPC signal received from the communication satellite. SC to send to
, the signal level of the PC signal is adjusted.

FIG. 2 is a block diagram showing the configuration of the transmission level controller 6 shown in FIG. 1. In this figure, 7 is a drive circuit, and 8 is a variable attenuator. The drive circuit 7 converts the output of the reception level detector 5 into a predetermined voltage value and controls the variable attenuator 8 to control the signal level of the transmission signal.

(Effects of the Invention) As explained in detail above, according to the present invention, each #l
A receiving level detector is provided in the receiver of the transmitting/receiving device for satellite communication at the receiving station, a transmitting level controller is provided in the transmitter, and the signal level of the SCPC signal received from the communication satellite is detected by the receiving level detector, and the signal level of the SCPC signal received from the communication satellite is detected by the receiving level detector. By adjusting the signal level of the SCPC signal that is fed back to the level controller and transmitted to the communication satellite by the satellite communication transceiver of each earth station, the signal level of the SCPC signal that the communication satellite receives from each earth station is equalized. multiple SCs on communication satellites
The influence of third-order cross modulation product (TM) when simultaneously amplifying PC signals is reduced, and the function as a communication satellite repeater is fully demonstrated. The present invention has the above effects.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a transmission level controller of the present invention. 1... Transmitting/receiving antenna, 2... Transmitting/receiving duplexer, 3...
... Receiver, 4... Transmitter, 5... Reception level detector, 6... Transmission level controller, 7... Drive circuit, 8... Variable attenuator.

Claims (1)

[Claims] a transmitting/receiving antenna directed toward a communication satellite; a receiver demodulating a signal received by the transmitting/receiving antenna; a transmitter generating a signal to be transmitted from the transmitting/receiving antenna; and connecting the transmitting/receiving antenna to the receiver and the transmitter. It consists of a transmitter/receiver branching filter, and the SC
In a satellite communication transmitter/receiver for an earth station that performs PC communication, the receiver is provided with a reception level detection means for detecting a reception signal level, and the transmitter transmits data according to the reception signal level detected by the reception level detection means. A transmitter/receiver for satellite communication, characterized in that it is provided with a transmission level control means for controlling a signal level.