JPH02159805A - Nonlinear compensator - Google Patents

Abstract

PURPOSE:To easily transit between a nonlinear compensation circuit and a linear circuit without momentary interruption by providing the nonlinear compensation circuit and a variable attenuator in parallel and controlling the variable attenuator electronically. CONSTITUTION:A branching filter 1 branches an inputted high frequency signal into two high frequency signals with large and small power and different branch ratio. The variable attenuator 2 receives a larger power of the branching filter 1 to control the attenuation. Moreover, the nonlinear compensation circuit 4 receives the smaller power from the branch device 1 to compensate the distortion in the high frequency signal. Through the constitution above, when the circuit 4 is turned on, the attenuation of the attenuator 2 is taken large and when the circuit 4 is turned off, the attenuation is minimized. That is, since the input terminal 20 and the output terminal 21 are coupled with either by the circuit 4 or the attenuator 2 whose attenuation is zero, the deice without momentary interruption of the high frequency signal is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a nonlinear compensation device that is added to a microwave band power amplifier and has a switching function between a nonlinear compensation circuit and a linear circuit.

[Conventional technology]

Conventionally, nonlinear compensation circuits have been used to compensate for distortion in microwave power amplifiers, but the overall characteristics of the microwave power amplifiers or nonlinear compensation circuits have deteriorated due to aging, etc., and transmission using only microwave power amplifiers has become difficult. If you want to do this, by switching to a linear circuit, you can use the microwave band power amplifier as is and secure communication. Such switching between the nonlinear compensation circuit and the linear circuit is accomplished by providing a nonlinear compensation circuit 23 and a linear circuit 24 that bypasses the nonlinear compensation circuit 23, as shown in the block diagram of FIG. 3, and switching between them. In FIG. 3, a signal input from an input terminal 20 is switched by a coaxial switch 22, passes through a nonlinear compensation circuit 23 or a linear circuit 24, and is output from an output terminal 21.

[Problem to be solved by the invention]

Switching between the conventional nonlinear compensation circuit and the linear circuit described above is as follows:
A coaxial switch is used to switch high frequency signals. Furthermore, since the wiring from the coaxial switch to the linear circuit bypasses the nonlinear compensation circuit, there is a drawback that the entire device including the switching system becomes larger and heavier. Also,
Another drawback is that the reliability of high-frequency signal transmission during switching also deteriorates.

[Means to solve the problem]

The nonlinear compensation device of the present invention includes a branch circuit that divides a high frequency signal into two branch signals, a nonlinear compensation circuit that inputs one of the branch signals and compensates for distortion, and a nonlinear compensation circuit that inputs one of the branch signals and compensates for distortion. A linear circuit having at least the variable attenuator of a variable attenuator and a high frequency amplifier that input and change the amount of attenuation according to a control signal, and a synthesizing circuit that synthesizes each output signal of the nonlinear compensation circuit and the linear circuit. , the control signal is applied from the outside to set the attenuation to zero or a predetermined attenuation, or the control signal is applied from the nonlinear compensation circuit to set the attenuation to zero or a predetermined attenuation. ing.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of a first embodiment of the present invention. The first embodiment includes a high-frequency signal input terminal 20, a splitter 1 that branches the input high-frequency signal into two high-frequency signals of high power and low power with different branching ratios, and a larger power of the splitter 1. , input the smaller power of the variable attenuator 2 that can control the amount of attenuation, and the brancher 1, and output the outputs of the nonlinear compensation circuit 4, the variable attenuator 2, and the nonlinear compensation circuit 23 that compensate for the distortion of the high frequency signal. It is composed of a combiner 3 having the same branching ratio as that of the combining splitter 1, and an output terminal 21 from which the combined output is taken out. Here, variable attenuator 2 outputs a variable bias current to P by a control signal from an external terminal.
It can be applied to an IN diode to change the amount of attenuation of high frequency signals.

Furthermore, the nonlinear compensation circuit 4 can operate or disable the circuit by turning on/off a voltage to this circuit. The operation of this embodiment is such that when the nonlinear compensation circuit 4 is on, a bias current flows through the PIN diode of the variable attenuator 2 to obtain a large amount of attenuation, and when the nonlinear compensation circuit 4 is off, the bias current of the PIN diode is zero. In other words, the input terminal 20 and the output terminal 21 are coupled by either the nonlinear compensation circuit 4 or the variable attenuator 4 with zero attenuation, so that the attenuation is minimized. A device without momentary signal interruption can be obtained. In addition, in this embodiment, the branching and combining ratio of the splitter 11 and combiner 3 is determined by the variable attenuator 2 in order to mainly operate the bypass circuit.
Although we have adopted a method in which a larger amount of power is supplied to the other side, the opposite configuration is also possible.

As an application example of this embodiment, the bias line 5 of the variable attenuator 2
is provided between the nonlinear compensation circuit 4 and the nonlinear compensation circuit 4.
A bias current is supplied from a bias power supply provided inside. In a circuit having such a configuration, by turning off the power of the distortion compensation circuit itself, the bias current of the variable attenuator 2 is automatically turned off, and the amount of attenuation is minimized.

Next, a second embodiment of the present invention will be described. FIG. 2 is a block diagram of a second embodiment of the invention. This circuit has the same configuration as the first embodiment except that an amplifier 6 is added in series with the variable attenuator 2. By adding the amplifier 6, it is possible to form not only a bypass in which the amount of attenuation of the variable attenuator 2 is zero, but also a linear circuit having a gain.

〔Effect of the invention〕

As explained above, the present invention provides a nonlinear compensation circuit and a variable attenuator in parallel, and electronically controls the variable attenuator, thereby making it possible to easily transition to a nonlinear compensation circuit and a linear circuit without momentary interruption. There is an effect that can be done. In addition, since no coaxial switch is used, it can be made smaller and lighter, and has the effect of increasing reliability.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a first embodiment of the present invention, FIG. 2 is a block diagram of a second embodiment of the present invention, and FIG. 3 is a block diagram of a conventional nonlinear compensator. . DESCRIPTION OF SYMBOLS 1... Brancher, 2... Variable attenuator, 3... Combiner, 4... Nonlinear compensation circuit, 5... Bias line, 6
...Amplifier, 20...Input terminal, 21...Output terminal, 22...Coaxial switch, 23...Nonlinear compensation circuit, 24...Linear circuit.

Claims (1)

[Claims] A branch circuit that divides a high frequency signal into two branch signals, a nonlinear compensation circuit that inputs one of the branch signals and compensates for distortion, and a nonlinear compensation circuit that inputs the other branch signal and adjusts the amount of attenuation according to a control signal. A linear circuit having at least the variable attenuator among a variable attenuator and a high frequency amplifier that changes the attenuation amount is zero or a predetermined attenuation amount, or the control signal is applied from the nonlinear compensation circuit and the attenuation amount is zero or a predetermined attenuation amount. Device.