JPS62118622A - Agc amplifier - Google Patents

Abstract

PURPOSE:To allow an output power to be adjusted easily by an external command by providing a circuit receiving a digital signal representing a detection voltage corresponding to an indication of a high frequency power and converting a detection voltage corresponding to the indication read out of a storage circuit into a high frequency power control voltage. CONSTITUTION:A command inputted from a command input terminal 9 is converted into a parallel signal by an S/P converter 10 and a memory circuit 11 stores an address designated by a detection voltage corresponding to the indication represented by the parallel signal. The detection voltage corresponding to the indication is read continuously and fed to a D/A converter 12, where the detection voltage corresponding to the indication of digital representation read from the memory circuit 11 is converted into an analog voltage 108. A comparison amplifier 7 compares a preset voltage to the memory circuit 11 with a detection voltage 106 detected actually by a detector 6 and applies a bias current to a variable attenuator 3 until the both reach an identical value.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an AGC amplifier, particularly an AGC amplifier for use on a satellite.

(Prior art) An AGC amplifier includes a detector that detects a part of the output No. 2 of the amplifier, and a comparator amplifier that compares the voltage difference between the output voltage of this detector and a standard voltage. Some devices allow the output power of the amplifier to be controlled by changing the variable attenuation amount of the variable attenuator depending on the voltage.

A circuit example of such an AGC amplifier is shown in FIG.

In this figure, numeral 1 is a high frequency input terminal, and 2 is a high frequency output terminal. Reference numeral 3 denotes a variable attenuator connected to the high frequency input terminal 1, which can be constructed of, for example, a PIN diode. 4 is an amplifier connected to variable attenuator 3;
A gravity distributor 5 is connected to this amplifier 4. The power divider 5 is connected to the Takaoka wave output terminal 2 and also to the wave detector 6. The comparison amplifier 7 is connected between the detector 6 and the bias terminal 3A of the variable attenuator 3, and the standard voltage circuit 20 is connected to the input stage of the comparison amplifier 7. This standard voltage circuit 20 is composed of voltage dividing resistors 21 and 22, a resistor 23, and a diode 24. The output of the amplifier 4 is distributed to the high frequency output terminal 2 and the detector 6 by the power divider 5, and the detected voltage 106 obtained by detection by the detector 105 is compared with a standard voltage 120 by the comparator amplifier 7.

The comparison amplifier 7 increases the amount of attenuation of the variable attenuator 3 when the detected voltage 106 is higher than the standard voltage 120, and conversely increases the amount of attenuation of the variable attenuator 3 when the detected voltage 106 is smaller than the standard voltage 120.
07 is applied to the bias terminal 3A of the variable attenuator 3. Due to the negative feedback loop having such a configuration, the output power of the AGC amplifier shown in FIG. 2 is controlled to a preset value even if the input power of the high frequency input terminal 1 changes.

(Problems to be Solved by the Invention) In AGC amplifiers for satellite access, it is desired to be able to adjust the output power of the AGC amplifier according to the communication state. However, in the conventional AGC amplifier shown in FIG. 2, in order to finely adjust the output power, the resistance ratio of the voltage dividing resistors 21 and 22 of the standard voltage circuit 20 is changed, and the standard voltage 120 applied to the comparator amplifier 7 is adjusted. It needs to change. Therefore, a problem arises in the conventional AGC amplifier in that the set value cannot be easily changed.

The present invention was developed in view of the above-mentioned circumstances, and an object of the present invention is to enable the output power of an AGC amplifier to be easily adjusted based on commands from a ground station, etc., depending on conditions such as communication status. .

(Means for Solving the Problems) Means provided by the present invention to solve the above-mentioned problems includes a variable attenuator that attenuates an input high frequency signal according to an attenuation amount control signal, and a variable attenuator that attenuates an input high frequency signal according to an attenuation amount control signal. an amplifier that amplifies the output; a detector that detects a part of the output of the amplifier to generate a detected voltage; and amplifies the pressure of the difference between the detected voltage and the high-frequency power control voltage and outputs it as the attenuation amount control signal. an AGC that amplifies the input high frequency signal to high frequency power according to the high frequency power control voltage and outputs the high frequency power according to the high frequency power control voltage;
The amplifier includes a circuit for receiving a digital signal representing the detected voltage corresponding to the indicated value of the high frequency power, a circuit for storing the detected voltage corresponding to the indicated value output from the receiving circuit, and reading from the memory circuit. and a circuit for converting the detected voltage corresponding to the indicated value into the high frequency power control voltage.

(Embodiment) An embodiment of the AGC amplifier of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing the AGC amplifier.

In this figure, numeral 1 is a high frequency input terminal, and 2 is a high frequency output terminal. A variable attenuator 3 is connected to the high frequency input terminal 1, and is composed of, for example, a PUN diode. 4 is an amplifier connected to variable attenuator 3,
A power divider 5 is connected to this amplifier 4. The power divider 5 is connected to the high frequency output terminal 2 and is also read directly by the wave detector 6. The detector 6 is connected to the first input terminal 7A of the comparison amplifier 7, and the output terminal 7C is connected to the bias terminal 3A of the variable attenuator 3.

In this embodiment, a voltage adjustment circuit 8 is further connected to the second input terminal 7B of the comparison amplifier 7. This voltage adjustment circuit 8 has a command input terminal 9 into which a command signal (command signal) representing a detected voltage 106 corresponding to the indicated value of high-frequency power at the high-frequency output terminal 2 can be input, and a serial terminal for receiving the command signal. - A parallel converter (hereinafter referred to as an S/P converter) 10, and a memory circuit 11 in which the detected voltage of the detector 6 corresponding to a predetermined output gravity at the high frequency output terminal 2 is stored in advance as a digital value as a set voltage value. , digital-to-analog converter (hereinafter referred to as D/
(abbreviated as A converter). Since the command signal from the ground station is sent as a serial signal, the commands input from the command input terminal 9 are converted into parallel signals by the S/P converter 10. Then, the memory circuit 11 that receives the parallel signal stores the address designated by the detected voltage corresponding to the instruction value, which is represented by the parallel signal.

The detected voltage corresponding to the indicated value can be read out continuously and supplied to the D/A converter 12. The D/A converter 12 converts the detected voltage corresponding to the digital representation of the instruction value read out from the memory circuit 11 into an analog value voltage 108 .

This analog voltage JE 108 is equal to the detected voltage 106 (analog value) when the high frequency power at the terminal 2 is the indicated value. Comparison amplifier 7 compares the voltage value preset in memory circuit 11 with the voltage value actually detected by detector 6 (detected voltage 106), and applies a bias current to variable attenuator 3 until both values become equal. Add. In this way, in the AGC amplifier of this embodiment, the output power can be determined according to the detected voltage stored at the address specified by the command signal. Therefore, in this embodiment, the output power can be easily adjusted by issuing an instruction from the ground station according to the communication state.

(Effects of the Invention) As described above in detail, according to the present invention, an AGC amplifier whose output power can be easily adjusted by an external command can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the AGC amplifier of the present invention, and FIG. 2 is a block diagram showing a conventional AGC amplifier. 1...High frequency input terminal, 2...High frequency output terminal, 3
... variable attenuator, 4... amplifier, 5... power divider, 6... detector, 7... comparison amplifier, 9... command input terminal, 10 command receiving circuit, 11. ...Memory circuit, 12...Digital-to-analog converter.

Claims (1)

[Claims] a variable attenuator that attenuates an input high frequency signal according to an attenuation amount control signal; an amplifier that amplifies the output of the variable attenuator; a detector that detects a part of the output of the amplifier to generate a detected voltage; a comparator amplifier that amplifies a voltage difference between a detection voltage and a high-frequency power control voltage and outputs the amplified voltage as the attenuation amount control signal, and amplifies the input high-frequency signal to high-frequency power according to the high-frequency power control voltage and outputs the amplified signal. The AGC amplifier includes a circuit for receiving a digital signal representing the detected voltage corresponding to the indicated value of the high frequency power, a circuit for storing the detected voltage corresponding to the indicated value of the output of the receiving circuit, and a circuit for storing the detected voltage corresponding to the indicated value of the output of the receiving circuit, and An AGC amplifier comprising: a circuit for converting the detected voltage corresponding to the indicated value into the high frequency power control voltage.