SU1156243A1 - Device for compressing signal - Google Patents

Abstract

A SIGNAL COMPRESSING DEVICE, containing an input phase inverter, the first and second channels, each of which includes adjustable 1st attenuator, the output of which is the output of the corresponding channel, and a comparator, as well as an algebraic adder, whose inputs are connected to the outputs of the channels, with the first inputs of the comparators each channel is combined and connected to a voltage source, characterized in that; in order to reduce nonlinear distortions, in each channel between the input of the phase inverter and the input of the adjustable attenuator a limiter is connected, the input of which is the input of the corresponding channel, an element is connected between the output of the comparator, the second input of which is connected to the output of the adjustable attenuator a memory in parallel with which the key is turned on, while the control input of the key of one channel is connected to (L output of the comparator of another channel).

Description

111 The invention relates to radio peaks and can be used in the transmission channels of analog signals, for example, in telephone communication devices, modulators of radio transmitters, etc. The purpose of the invention is to reduce nonlinear distortion. Fig. 1 shows a structural electrical circuit of the signal compression device in Fig. 2, time diagrams of the operation of the signal compression device. The signal compression device contains input phase inverter 1, first 2 and second 3 channels, limiters A, adjustable attenuators 5, Comparato 6, elements 7 of memory, keys 8, algebraic adder 9, as well as resistors 10 and field-effect transistors 11 and reference source 12 wives The signal compression device operates as follows. The input of the phase inverter 1 receives the voltage from the signal source. Through the limiters 4 from the output of the input phase inverter 1 signal are fed to the signal inputs of the adjustable attenuators 5. The adjustable attenuators 5 can be made, for example, in the form of series-connected resistors 10 and field-effect transistors 11 (figure 1). From the outputs of the adjustable attenuators 5, the signals are sent to the algebraic adder 9 and the first inputs of the comparators 6. If the amplitude of the signal at the second input of one of the comparators, for example, comparator 6, first kangsha 2 exceeds the value E, the comparator b is triggered; the attenuator 5 of the first channel 2 through the memory element 7 receives a signal, and the transmission coefficient of the adjustable attenuator 5 decreases with a value at which the amplitudes of the signal at its output, and, therefore, at the input of the comparator 6 CTEHO Vits E. signal equal size are grappling variable attenuator 5 .2 first channel is stored by the element 7 memory. When the first channel 2 compressor 6 is triggered, the key 8 of the second channel 3 resets the 3rd memory of the control signal of the third channel also triggers. If the amplitude of the signal in one of the channels after reaching the maximum remains unchanged or decreases, then the gain of the adjustable attenuator 5 of the same channel 3 remains unchanged until the sign of the amplitude of the signal is changed and the follower of the comparator 6 of another channel is changed. Since at a given time a signal can exist only in one of the channels, it is obvious that the memory of the control signal of any adjustable attenuator is reset and the initial transfer coefficient is restored when there is no signal at its input. The operation of the compressing device when a sinusoidal voltage is applied to its input (Fig. 2a) is illustrated by time diagrams presented in Fig. 2 (the form of the voltages at the outputs of the limiters are shown in Figs. 2, 5, .E and Fig. 2, 2), which displays the changes in the transmission factors of reggly in Ix attenuators 5 of the first 2 and second 3 channels when the comparators 6 are triggered, the voltage at the outputs of the adjustable attenuators 5 (figure 2, g), at the output of the algebraic adder 9 (figure 2h). The plots (Fig. 2g, e,) show that the transmission coefficient of the adjustable attenuators 5 is non-linear from the time instant ut corresponding to the compression start threshold to the time at the corresponding maximum amplitude of the input signal. The greater the degree of compression (the smaller E), the smaller At. In this case, the transmission coefficient of each of the adjustable attenuators 5 is nonlinear for r time, and nonlinear phenomena in the signal at the output of the algebraic adder 9 appear for, i.e. during half the time of the compression process, so they introduce less nonlinear distortion, since in the considered mode the harmonic coefficient is less, it means less and the products of the interaction of harmonics with the signal spectrum. Thus, the proposed device allows to significantly reduce the nonlinear distortion during compression of the signal amplitude.

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Claims (1)

A SIGNAL COMPRESSION DEVICE containing an input bass reflex, first and second channels, each of which includes an adjustable attenuator, the output of which is the output of the corresponding channel, and a comparator, as well as an algebraic adder, the inputs of which are connected to the outputs of the channels, while the first inputs of the comparators of the channel are combined and connected to a reference voltage source, characterized in that; in order to reduce non-linear distortions, a limiter is included in each channel between the output of the input phase inverter and the input of the adjustable attenuator, the input of which is the input of the corresponding channel, between the output of the comparator, the second input of which is connected to the output of the adjustable attenuator, and the control input of the adjustable attenuator is connected, in parallel the output of which I key is included, while the control input of the key of one channel is connected to the output of the comparator of the other channel.