SU801230A1 - Device for automatic regulation of amplification - Google Patents

Description

The invention relates to radio engineering and can be used to stabilize the amplitude of a sequence of pulses in a wide range of input signals while maintaining the shape of stabilized pulses in the presence of interference. A device for automatic gain control is known, comprising an integrator connected in series, an adjustable amplifier, the other input of which is the device input, and a first comparison element, on the other input of which a reference signal is fed, a multiplier and connected in series a block of statistical detection of the pulse existence interval and LlJ pulse disappearance detector. However, the known device has a low accuracy of maintaining the level of the input pulsed signal under the influence of low-frequency and high-frequency interference. The purpose of the invention is to increase the accuracy of maintaining the input pulse signal level when exposed to low-frequency and high-frequency interference. This goal is achieved by the fact that in a device for automatic gain control, comprising an integrator connected in series, an adjustable amplifier, the other input of which is the device input, and the first comparison element, the first reference signal is fed to the other input, the multiplier and the statistical detection unit connected in series the interval of existence of the pulse signal and the detector of the disappearance of the pulse sequence, between the output of the Detector of the disappearance of the pulse sequence and the input of the integrator are connected in parallel a first key, the other input of which is connected to the output of the first comparison element, and a second

a key whose other input is connected to the output of the multiplier, between the output of the adjustable amplifier and the input of the multiplier is connected in series the subtractor, high-pass filter, adder and second comparison element, to the other input of which a second reference signal is fed, while the input of the pulse detection statistical block connected to the output of the adder, and the output to the other inputs of the subtractor and the adder, another input of the multiplier is connected to the output of the block of statistical detection of the interval with pulse, and the output with another input of the second key.

The drawing shows a structural electrical circuit of the proposed device.

The device comprises an integrator, an adjustable amplifier 2, a first comparison element 3, a multiplier 4, a statistical detection interval 5 of a pulse signal existence interval, a pulse sequence disappearance detector 6, a first key 7, a second key 8, a high-pass filter 9, an adder 10, a second element 11 comparison and subtractor 12.

The device works as follows.

In the absence of a pulsed signal, when only low-frequency noise and high-frequency noise are acting on the input, filter 9 suppresses low-frequency noise and passes high-frequency noise to the device. Unit 5 does not respond to high-frequency interference. The detector 6 opens the second key 8 and closes the first key 7, connected to the input of the integrator 1, the first element 3 of the comparison with a predetermined level. In this mode of operation, the device stabilizes the low-frequency interference, keeping it at a predetermined level.

Such a circuitry avoids saturation of the adjustable amplifier 2 at the moment the device is turned on or when the pulse sequence is lost if a low-frequency disturbance at its input.

When a sequence of information pulses arrives at the input of a device, block 5, which uses an active probabilistic relay, generates the leading edge of a pulse representing the probability that the pulse signal exceeds a threshold level. The voltage jump from the output of block 5 is fed to the second input of the subtractor 12 and to the second input of the adder 1O. At the point in time when the output signal becomes less than the threshold level, block 5 forms the falling edge of the pulse. The detector 6 opens the first key 7 and closes the second key

8. Pulse signals simultaneously

step on the second comparison element 11, where the pulse is compared with a given level of stabilization. The error signal from the output of the second comparison element 11 is fed to

multiply input 4, to the second input of which a signal is supplied from the output of block 5. The signal from the output of multiplier 4 through the second key 8 is fed to integrator 1, where it is integrated, turning into a control signal that is fed to the control input of the control of my amplifier 2. Constant nna time. integrator 1 is selected based on the maximum level of high-frequency

interference acting at the input of the device, and the desired duration of the transition process, during which a pulse sequence of any amplitude results in a pulse sequence of a given amplitude.

Claims (1)

Formula A device for automatic gain control, containing a serially connected integrator, an adjustable amplifier whose other input is the device input, and a first comparison element, to the other input of which a first reference signal is fed, a multiplier and a serially connected unit for detecting the pulse existence interval and the detector of the disappearance of the pulse sequence, which is the fact that, in order to increase the accuracy of maintaining the level of the input impulses a low-frequency and high-frequency interference signal, between the output of the disappearance detector of the pulse sequence and the integrator input are connected in parallel the first key, the other input of which is connected to the output of the first comparison element, and the second key, the other input of which is connected to the output of the multiplier, between the output of the adjustable amplifier and multiplier input A sequencer, a high-pass filter, an adder and a second comparison element are connected in series, to another input of which a second reference signal is fed, while the input of the statistical detection unit for the existence of a pulse signal is connected to the output of the adder, and the output to other inputs of the subtractor and adder, and another the multiplier is connected to the output of the statistical detection unit for the existence interval of the pulse signal and the output to the other input of the second key. Sources of information taken into account during the examination 1. USSR author's certificate NI 618835, cl. H 03 G 3/20, 1976 (prototype).