JPS63299530A - Satellite communication transmitter - Google Patents

Abstract

PURPOSE:To keep the transmission electric power at a fixed level by controlling the attenuation value of a variable attenuator based on the desired transmission output level of each modulator performing a transmitting action as well as the non-linear input/output characteristics of a large electric power amplifier and compensating the gain fluctuation due to said input/output characteristics. CONSTITUTION:The desired transmission electric power of each carrier and the non-linear input/output characteristics of a large electric power amplifier 5 are previously written and stored into a transmission gain control computing element 7. The ON/OFF states of the transmission carriers are controlled by modulators 11-1n and these control information are supplied to the element 7. The element 7 calculates the total transmission electric energy and the desired gain controlled variable and controls the attenuation value of a variable attenuator 4 to compensate the gain fluctuation due to the non-linear input/output characteristics of the amplifier 5. Thus the transmission gain fluctuation is corrected and the transmission electric power of each carrier is kept at constant level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a satellite communication transmitting device equipped with gain control means.

[Prior Art] Conventionally, many satellite communication transmitting devices have been equipped with gain control means composed of a transmission power monitor and a transmission gain controller in order to keep transmission power constant.

[Problems to be Solved] However, such conventional gain control means requires the above-mentioned transmission power monitor to constantly monitor the transmission power and control its value, making the entire device complex and difficult. There was a problem that it was expensive.

In particular, when transmitting multiple frequency-divided waves, it is necessary to provide a transmission power monitor and a transmission gain controller for each carrier, which makes the entire device more complex and expensive. was there.

The present invention was made in view of these problems, and its ``first objective is to provide a satellite communication transmitting device that can maintain constant transmission power without making the entire device complicated and expensive. Our goal is to provide the following.

[Means for Solving Problems] In order to solve the above-mentioned problems, the present invention provides a plurality of modulators, an intermediate frequency multiplexer that combines the outputs of these modulators, and an intermediate frequency multiplexer that combines the outputs of these modulators. a high-power amplifier that commonly amplifies the output signals of the respective modulators outputted from the intermediate frequency multiplexer, and a high-power amplifier that transmits multiple frequency-divided waves via an antenna. The amount of attenuation of the variable attenuator is determined based on the variable attenuator provided between the power amplifier and the number of modulators performing transmission operations, the required transmission output level of each modulator, and the input/output characteristics of the high power amplifier. 9 [Example] Next, a preferred embodiment of the present invention is shown in the drawings. I will explain based on this.

FIG. 1 shows a preferred example of a satellite communication transmitter according to the present invention.

In the figure, the outputs of the modulators 11 .

The output of the upconverter 3 is input to a large power amplifier 5 via a variable attenuator 4 for gain control, where it is commonly amplified and then transmitted from an antenna 6.

Carrier on/off information from the modulators 11 . . . 1 n is input to the transmission gain control calculator 7 . The transmission gain control calculator 7 also includes a variable attenuator 4 to perform gain control.
It is connected to the.

In the present invention, the variable attenuator 4 and the transmission gain control calculator 7 are used to control the gain of the transmission power as follows.

First, the required transmission power of each carrier and the nonlinear input/output characteristics of the high power amplifier 5 are written and stored in the transmission gain control calculator 7 in advance.

Also, the on/off of the transmission carrier is controlled by the modulators 11...1o.
The control information is transmitted to the transmission gain control calculator 7.
is input.

Then, the transmission gain control calculator 7 calculates the total amount of transmission power and the necessary gain control amount, adjusts the amount of attenuation of the variable attenuator 4 based on the calculated value, and adjusts the amount of attenuation of the variable attenuator 4 to increase the non-linearity of the large power amplifier 5. Compensates for gain fluctuations due to input/output characteristics.

By doing so, according to the present invention, transmission gain fluctuations are corrected and the transmission power of each carrier is kept constant.

[Effects of the Invention] As explained above, according to the present invention, it is possible to make the transmission power constant without using a transmission power monitor and a transmission gain controller for each carrier as in the past, and in particular, Even if some carriers are turned on or off and the output of a large power amplifier fluctuates greatly, it is possible to suppress the gain fluctuation of the transmission power within the standard without constantly monitoring the transmission power of the carrier.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing a preferred example of a satellite communication transmitting device according to the present invention. 11...1n...Modulator, 2...Intermediate frequency multiplexer, 4...Variable attenuator, 5...High power amplifier, 6...Antenna, 7...Transmission gain control Arithmetic unit.

Claims (1)

[Claims] A plurality of modulators, an intermediate frequency multiplexer that combines the outputs of the respective modulators, and a common amplification of the output signals of the respective modulators outputted through the intermediate frequency multiplexer. a high-power amplifier, and a variable attenuator provided between the intermediate frequency multiplexer and the high-power amplifier; The amount of attenuation of the variable attenuator is adjusted based on the number of modulators performing transmission operation, the required transmission output level of each modulator, and the input/output characteristics of the high power amplifier, and the amount of attenuation is adjusted based on the nonlinear input/output characteristics of the high power amplifier. A satellite communication transmitter comprising: a transmission gain control calculator that compensates for gain fluctuations;