SU1190211A1 - Device for measuring temperature - Google Patents

Abstract

A DEVICE FOR TEMPERATURE MEASUREMENT, containing sequentially connected broadband amplifiers, a measuring device and a feedback circuit of the amplifier, a surface acoustic waves delay line, which is a sensory element of the sensor. And consisting of a sound line made of a material having. temperature dependence of the propagation time of surface acoustic waves on one of the surfaces of which in one acoustic channel two counterpins are identical with each other A rotary converter, the distance between the centers of which is a multiple of an integer number of wavelengths, is characterized in that, in order to increase the temperature measurement accuracy by providing a monofrequency mode of operation and a high electrical quality factor of the oscillating system, an additional wideband amplifier and two identical broadband opposite ones are introduced into it -plug transducers located in the same acoustic channel between the first and the second psbro-co lane interdigital transducers and on The second amplifier is connected to the feedback circuit, and the distance from the center of any internal counter-pin converter to the center of the most extreme opposite-pin converter close to it, and the receiver is equal to the same distance from the center of another internal NS to the center of another NS closest to it the extreme interdigital transducer and a multiple of an integer number of wavelengths.

Description

one

The invention relates to a technique of heat engineering measurements and can be used in temperature measurement and control systems.

The purpose of the invention is to improve the accuracy of temperature measurement by providing a mono-frequency mode of operation and high electrical quality of an oscillating system.

The drawing shows the functional diagram of the temperature sensor.

On the acoustic duct 1 of the surface acoustic wave (SAW) in the acoustic channel 2, broadband interdigital transducers (IDT) 3-6 SAW are placed.

LSI 3 and b are connected, respectively, to the input and output of amplifier 7, and IDT 4 and 5, respectively, to the output and input of amplifier 8, forming a generator, to the output of which measuring device 9 is connected ..

The device works as follows.

The frequency of the generator is a function of the temperature being measured. When the temperature changes, the path and the velocity of the SAW propagation along the surface of the sensing element, which is the duct 1 of the SAW, and therefore the output frequency of the generator changes.

Improving the accuracy of temperature measurement is provided by the high frequency stability of the generator due to the provision of monofrequency operation and the high electrical quality of the oscillatory system of the sensitive element, which was made possible by placing the method with broadband identical IDT 3 and 6 SAWs and additionally two more identical broadband IDT 4 and 5 SAW connected respectively to the output and the input of the broadband amplification, 8, the gain of which is chosen not 02112

just a smaller (by 0%) value at which self-excitation along this circuit would occur. The autogeneration mode of the temperature sensor is provided by the appropriate choice of the value of the coefficient 4) of the wideband amplifier 7 amplifier. A necessary condition for the normal operation of the proposed Temperature Sensor is

0 stalling of the autogeneration mode when the supply voltage is turned off for one / one of the usstiteli 5, for example, amplifier 2, the distance between the centers of the broadband IDT 4 and 5 SAW is selected

5 equal to N, where N is an integer, L is the length of the surfactant. Correspondingly, a multiple integer number of wavelengths and the distance between the centers of broadband IDT 3 and 4 and the centers

0 broadband VSP 5 and 6 surfactants - K L, where K is an integer.

The conclusion about the high electrical quality factor of the temperature sensor, performed in full accordance with the above description, has been verified experimentally. The sensitive element is made on a piezoelectric plate made of lithium niobate (LiNbOj) YZ - a slice, on the working surface of which four identical broadband HICPs are made using photolithographic methods, each of which contains 20 pairs of split electrodes. To study the amplitude, 5 tudno-frequency response (AFC) of the through path of the broadband transducer UTP 6 SAW open, the voltage from the output of amplifier 7 and connected to the output of the frequency characteristics meter (type X1-47), and the output of amplifier 7 is connected to the same input frequency response meter.

The experimental frequency response of the through-path of the temperature sensor contains one narrow-band peak, the quality factor of which is 3000.

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Claims (1)

A TEMPERATURE MEASUREMENT device containing a broadband amplifier connected in series, a measuring device and a surface acoustic wave delay line connected to the amplifier feedback circuit, which is a sensitive element of the sensor, and consisting of a sound duct made of a material with a temperature dependence of the propagation time of surface acoustic waves * on one of the surfaces of which in the same acoustic channel two identical interdigital generator, the distance between the centers of which is a multiple of an integer number of wavelengths, characterized in that, in order to improve the accuracy of temperature measurement by ensuring a monofrequency mode of operation and high electric quality factor of the oscillating system, an additional broadband amplifier and two identical broadband interdigital interconnectors are introduced into it transducers located in the same acoustic channel between the first and second broadband interdigital transducers and included in the circuit connection of the second amplifier, while the distance from the center of any internal interdigital converter to the center of the nearest extreme interdigital converter is equal to the same distance from the center of another internal to the center of the other extreme extreme interdigital converter and is a multiple of an integer number of lengths waves.