SU930577A1 - Frequency discriminator - Google Patents

Description

(5) FREQUENCY DISCRIMINATOR

I

The invention relates to a technique for receiving and transmitting signals, and can be used to detect frequency modulated signals, as well as in frequency stabilization systems.

Known frequency discriminator on surface acoustic waves, containing one exciter and four receiving. Common pin-type transducers located on the piezoelectric substrate, as well as two amplitude detectors, all of which are connected to the corresponding terminals of the receiving counter-converters tj.

However, this frequency discriminator has a low slope of discriminatory characteristics.

The aim of the invention is to increase the slope of the discriminatory characteristic.

For this purpose, in a frequency discriminator on surface acoustic waves containing one exciting and four receiving interdigital transducers located on a piezoelectric substrate, as well as two amplitude detectors, the inputs of which are connected to the corresponding terminals of receiving counter-pin transducers, receiving counter - pin converters are arranged in pairs on opposite sides of the excitation of the counter-1 converters, with receiving counter-pin converters of hydrochloric pairs included under, and another - oppositely.

The drawing shows a structural electrical circuit of a frequency drive {zhminator. .

Claims (1)

The frequency discriminator contains an exciter counter-pin transducer: receiver 1, receiving counter-transducers2-3 located on a piezoelectric substrate (not shown, amplitude detectors 6, 7) The device works as follows. propagates in the direction of both pairs of receiving interdigital transducers 2, 3 and i, 5 in the form of an acoustic surface wave. The interdigital transducers 2, 3 and, 5 of each pair of reciprocating Aod. A pair of wind-pin converters 2, .3 is turned on so that at points 8, 9 there is a voltage proportional to the sum, and at points 10, 11 another pair of incident-shyyryov converters, 5 differences signals from each head-to-pin converter 2.3 and As a result of the interference of acoustic surface waves, the signal at points 8, 9 turns out to be proportional to COS tf t, cos and at points 10, COSdt, where | b is the propagation constant; input signal frequency; VR is the propagation velocity of the acoustic surface wave. After detection by amplitude detectors 6 and 7 and subtraction, since the diodes of amplitude detectors 6 and 7 are turned on, the output points 12, 13 receive a signal proportional to cos / JueL, which is a characteristic of the frequency discriminator. The parameters of the reciprocal transducers 2, 3, and 5 are chosen in such a way as to eliminate the ambiguity of the discriminatory characteristic caused by the cosine frequency. The solution of the discriminatory characteristic is selected by the spacing Act. Execution of a circuit with one exciting and four receiving interdigital transducers, arranged in pairs on opposite sides with respect to the exciting one, ensures a gain in transfer coefficient and thereby increases the slope of the discriminatory characteristic. The invention of the frequency discriminator on surface acoustic waves, containing one exciting and four receiving interdigital transducers located on a piezoelectric substrate, as well as Two amplitude detectors, the inputs of which are connected to the corresponding outputs of the receiving interdigital transducers, distinguished by the fact that the purpose of increasing the torsional characteristics of the discriminatory characteristics, the receiving reciprocating converters, the tenants are located in pairs on opposite sides of the exciting part a pin converter, with receiving counter-pin converters, the spreaders of one pair are turned on according to, and the other on the opposite side. Sources of information taken into account in the examination 1. Int. Spec. Semin. Compon. Perform, and Syst. Appl. Syrf. Acoust. Wave Devices, 1973, London, 1973, c. 152-166 (prototype).