SU1504784A1 - Detector of am signals - Google Patents

Abstract

The invention relates to radio engineering. The purpose of the invention is to improve the detection accuracy. The detector contains a full-wave precision rectifier 1, keys 6 and 7, a linear circuit OR 8, a null organ 11, a differentiation element 12, shapers 13 and 14 pulses, an AND 15 element, a comparator 16 and amplitude detectors 19 and 20. The goal is achieved by introducing input 1, comparator 16, continuously "following" the voltage difference across capacitors 4 and 5, AND 15 and the output linear circuit OR 8, which operates as a voltage follower, but repeats the voltage of that input, which at a given time is n the greatest. 3 il.

Description

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The invention relates to radio engineering and can be used in devices for demodulating amplitude modulated signals.

The purpose of the invention is to improve the detection accuracy.

FIG. Figure 1 shows the structural electrical circuit of the detector of amplitude-modulated signals; in fig. 2 - diagrams explaining his work; in fig. 3 shows an embodiment of a detector of polar and modulated signals.

The detector of amplitude-modulated signals contains a full-wave rectifier 1, the first 2 and second 3 operational amplifiers, the first 4 and second 5 capacitors, the first 6 and second 7 keys, the linear circuit OR 8, the first 9 and second 10 resistors, the zero-organ 11, differentiation element 12, first 13 and second 14 pulse formers, element 15, comparator 16, first 17 and second 18 diodes. In this case, the first 19 and second 20-amplitude detectors include, respectively, amplifiers 2 and 3, resistors 9 and 10, diodes 17, 18, capacitors 4, 5.

The detector of polarized modulated signals (Fig. 3) contains the first 21 and second 22 counting triggers, the first, second, third, and fourth one-oscillators 23 ± 26, respectively.

The detector amplitude-modulated signals is as follows.

The input signal (Fig. 2a) is fed to the inputs of the full-wave precision rectifier 1 and the first null organ 11, which converts the periodic input signal of a sinusoidal form into a square-wave pulse voltage. Differentiation element 12 alternately launches the first 13 and second 14 pulse generators, controlling the operation of the first 6 and second 7. keys, performed discharge of the first and second capacitors 4 and 5, respectively (Fig. 2c, d). Applying voltage from the output of the full-wave rectifier 1 to the first input of the linear circuit OR 8 (Fig. 26) serves to maintain at its output an instantaneous signal amplitude value at the end of the integration process of the RC circuits consisting of the first resistor 9 and the first capacitor 4 and respectively the second resistor 10 and the second capacitor 5.

The discharge of the first 4 and second 5 capacitors is carried out at different times corresponding to half periods of the input signal. During the arrival of pulses from the output of the second driver 14 (during each, for example, the second half period, the carrier voltage) on. the second input element AND 15 voltage on the first condensate) e 4 will not drop to zero (Fig. 2e), since the second comparator 16 continuously monitors the voltage difference on the first and second capacitors 4, 5. As soon as this difference will become zero, the first key 6 through the element And 15 is opened. Therefore, with an increase in the input signal envelope, the pulses at the output of the element I 15 are absent, and with decreasing they appear (Fig. 2i),

The output linear circuit OR 8 works as a voltage follower, but at the same time repeats the voltage. The first input that is currently the largest (Fig. 2g).

The detector of polarized modulated signals (Fig. 3) consists of two identical amplitude modulated signal detectors (Fig. 1), which detect positive and negative half-waves of the carrier wave, respectively. The first 19 and second 20 counting triggers triggered by the front and rear edges of the pulses, as well as the first, second, third, and fourth single vibrators 21 - 24, are formed in the respective pulses of the control pulses. the accuracy of the selection envelopes. For additional smoothing of the output signals, it is enough to connect a low-pass filter with a constant time small relative to the period of the carrier frequency.

Claims (1)

Invention Formula Amplitude modulated signal detector containing the first amplitude detector, the code of which is connected to the first output of the first key, the second output of which is connected to the common bus, the second amplitude detector, the output of which is connected to the first output of the second key, the second you 1504 the waters of which are connected to the common bus, and the input of the first amplitude detector is connected to the input of the second amplitude; A null-body serially connected detector whose input is the input of an amplitude modulated signal detector, a differentiation element and a first pulse shaper, the output of which is connected by IQ to the control input of the second key, and a second pulse shaper whose input is connected to the output of the differentiation element , in order to improve the accuracy of detection, a series-connected OR linear circuit, a comparator and an AND element are introduced, 84o as well as a half-full-length precision — a rectifier whose input is connected to the input of a cult organ, and an output to the inputs of the first and second amplitude detectors and to the first input of the OR lily circuit; the comparator and, to the third input, the output of the second amplitude detector, and to the inverting input of the comparator, the output of the linear circuit OR is the output of the detector of amplitude-modulated signals, and the second input of the AND element is connected to the output of the second generator pulse pulses, and the output to the control input of the first key. d .-..- LTP FIG. 2 fie. J