SU1202028A1 - Device for stabilizing gain factor - Google Patents

Abstract

A DEVICE FOR STABILIZATION OF THE AMPLIFIER COEFFICIENT, containing an adjustable amplifier, between the output and the control input of which are connected in series a voltage divider, an adder, another input of which is connected to the input of the adjustable amplifier, a phase-sensitive rectifier and a low-pass filter, characterized in that, for the purpose of increasing the accuracy of stabilization, a comparator is introduced into it, the inputs of which are connected to the input of the adjustable amplifier and the output of the voltage divider, respectively, and the output to the control inlet of phase sensitive rectifier.

Description

The invention relates to radio engineering and can be used in radio transmitters and radio measuring devices.

The aim of the invention is to improve the accuracy of stabilization.

Fig. 1 shows a structural electrical circuit device for stabilizing a gain; 2-4 are timing diagrams explaining the principle of operation of the device.

The gain stabilization device comprises an adjustable amplifier 1, a voltage divider 2, an adder 3, an amplifier 4, a phase-sensitive expander 5, a low-pass filter 6 and a comparator 7.

The device works as follows.

The input signal and the output signal attenuated by divider 2 are summed by adder 3. The resulting total signal is amplified by amplifier 4, fed to a phase-sensitive rectifier 5 and, after averaging by low-pass filter 6, is used to control the gain of adjustable amplifier 1.

So, if the input signal Ugx and the signal at the output of divider 2 voltage and g are shifted in phase but equal in amplitude, then the signal U is on. the output of the comparator 7 will have the form shown in figsn. The amplified total signal and K (Ugy), where K is the gain factor of the amplifier 4, are fed to the input of the phase-sensitive rectifier 5.

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020282

At the output of the phase-sensitive rectifier 5, a signal is generated, shown in Fig. 26 by a solid line. Averaging this signal (shaded pulses) with the help of low-pass filter 6 generates voltage and controls the gain of adjustable amplifier 1. In the case of equal amplitudes 10 signals Ug and Ugy, the positive and negative shaded pulses are equal and the control output voltage filter 6 of the lower frequencies is zero if O (figure 2). five

If, due to the instability of the gain of the adjustable amplifier 1, the amplitude of the signal at the output of the divider 2 voltage 20 ™ increased in comparison with the signal and 5 (FIG. 3 a), then at the output of the phase-sensitive phase 5, the signal appears as shown in FIG. 35, at the end of which a control voltage U f of a positive sign appears at the output of the low-pass filter 6 (FIG. 3c). Otherwise, i.e. when the amplitude of the signal at the output of the voltage divider has decreased, compared with the input signal of the device (Fig.4 h and b), the voltage Uf will have a negative sign (Fig.4). Thus, an automatic control system 35 is formed in which a constant value of the gain of the adjustable amplifier 1 is maintained by the control voltage U b.

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Claims (1)

DEVICE STABILIZATION DEVICE, comprising an adjustable amplifier, between the output and the control input of which are connected in series a voltage divider, an adder, the other input of which is connected to the input of the adjustable amplifier, a phase-sensitive rectifier and a low-pass filter, characterized in that, in order to improve the accuracy stabilization, a comparator is introduced into it, the inputs of which are connected to the input of the adjustable amplifier and the output of the voltage divider, respectively, and the output to the control input phase-sensitive rectifier. Vvt.j