SU389488A1 - AUTOMATIC GAIN CONTROLLER - Google Patents

Description

I

The invention relates to automatic gain controllers (AGC) and is intended for use in information processing devices to maintain the root-mean-square value of the output signal with high accuracy when the input signal changes in a wide dynamic range.

There are known AGCs that contain in a direct circuit a series-connected controlled voltage divider: both the first amplifier and the feedback circuits — a module module whose output is connected to the first input of the adder, to the second input of which the output of the reference voltage source is connected. The output of the adder is connected via a second amplifier to the engine, which is mechanically connected to the tachogenerator and through a reducer with a controlled voltage divider.

However, the known AGCs have different reaction times for the same assignments at different initial levels of the input signal due to the fact that simultaneously with the transmission coefficient control in the forward circuit, the transmission coefficient and the AGC circuit also change. With the constant slope of the integrator characteristic, this is the cause of the variable Q-factor in the circuit, which is unacceptable when the reaction carries informative features.

The aim of the invention is to ensure the constancy of the quality factor of the AGC by changing the input signal in a wide dynamic range.

This goal is achieved by the fact that the regulator additionally contains a controlled voltage divider, inputs are connected to the tachogenerator and a reducer, and output to the third input of the adder.

The drawing shows a block diagram of the AGC.

Regulator contains controlled dividers.

voltage 1 n 2, amplifiers 3 and 4, source

support voltage 5, you are modzl-6,

tachogenerator 7, adder 8, engine 9 and

gearbox W.

AGC works as follows. The input signal i / nx is fed through a voltage divider / to the input of the 8 straight circuit amplifier and then as output L / L output to the AGC output and to the module 6 input. In this case, the transfer coefficient in the AGC circuit corresponds to the transfer ratio of the divider L From the output of the module output module signal / f / output /

Adder 8 is summed with the reference voltage Uo, coming from the source of the reference voltage 5, and with the tachometric feedback signal f / ng, coming from the tachogenerator 7 through the divider 2. Error

AU from adder 8 is fed to amplifier 4

and controls the rotation of the actuator motor I mechanically connected to the tachogenerator 7. The motor 9 through the gearbox 10 controls the divider / so that the error Ai / decreases: to zero, and the divider 2 so that the tachometric feedback coefficient, and hence the slope the characteristics of the integrator (amplifier 4 and motor) were changed in proportion to the coefficient of succession in the AGC circuit, depending on the level of the input signal.

In this way, the quality factor in the AGC circuit is kept constant.

Subject invention

An automatic gain control containing, in a direct circuit, a serially connected controlled voltage divider and a first amplifier, in a feedback circuit, a module receiver, the output of which is connected to the first input of the adder, to the second input of which the output of the reference voltage source is connected, the output of the adder through the second amplifier is connected to the engine, which is mechanically connected to the tachogenerator and through a reducer with a controlled voltage divider, characterized in that, in order to ensure constant quality factor 1P When the input signal changes in a wide dynamic range, the controller additionally contains a controlled voltage divider, the inputs connected to the tachogenerator and the gearbox, and the output to the third input of the adder.