SU1239532A1 - Frequency-type temperature sensor - Google Patents

Abstract

The invention relates to the field of measurement technology and can be used in devices and centralized information-measuring systems designed for BIJCOKO-accurate temperature measurement. The purpose of the invention is to simplify the design of the sensor. A divider across resistors 24 and 25 sets a constant bias at the base of transistor 2; the resistors 26 and 27 and the capacitor 28 provide About 24 (L "Ve Is Y / gz to with with O1 00 to

Description

automatic bias on the base of transistor 2 relative to its emitter. Two asynchronous frequencies are simultaneously generated in the sensor using one amplifying cascade, an optical FM transistor 2 and two resonant LC circuits 3 and A, and one temperature-sensitive quartz resonator 1 (RC). The condition of the phase balance of the bottom of both frequencies is provided by tuning each of the resonant ones. The invention relates to the field of measurement technology and can be used in devices and centralized information-measuring systems intended for high-precision temperature measurement.

The purpose of the invention is to simplify the design of the sensor.

The drawing shows the electrical circuit of the frequency temperature sensor

The sensor contains a temperature-sensitive quartz resonator 1, included in the frequency-driving circuit of a self-oscillating oscillator, whose amplifying stage is made on a bipolar transistor 2, two parallel resonant LC circuits 3 and 4, formed by inductors 5 and 6 and capacitors 7 and 8 and tuned

on different natural frequencies of mechanical oscillations of the quartz resonator 1, mixer 9, made in the form of an LG circuit in the composition of inductor Y and capacitor 11, voltage limiters 12 and 13, made on nonlinear elements in the form of a chain of series-connected resistors and pairs of counter-connected semiconductor diodes (resistor 14 and diode 15 and 16, resistor 17 and diodes 18 and 19).

Both resonant LC circuits 3 and 4 are connected inductively by means of communication coils 20 and 21 in series with mixer 9 in the collector circuit of transistor 2 and through coupling capacitors 22 and 23 in series with the quartz resonator 1 in the positive feedback circuit of the generator

tours (RC) 3 and 4 to one of the frequencies KP 1 and their connection to the amplifying stage of the generator using communication coils 20 and 21 in the collector circuit of transistor 2, and the amplitude balance condition is provided by switching off the voltage suppressors 12 at the output of the RK 3 and 4 and 13 and the operation of transistor 2 in the linear part of the characteristic for each of the generated frequencies, 1 sludge.

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between the collector. transistor 2 and its base.

A divider on resistors 24 and 25 sets the required constant bias on the base of transistor 2; resistors 26 and 27 and capacitor 28 provide automatic mixing at the base of transistor 2 relative to its emitter.

The operation of the sensor is based on the fact that any crystal resonator has several natural frequencies due to mechanical oscillations of various types (compression-tension, shear, bending, torsion, etc.). At the same time, the influence of external influences, including temperature, on the natural vibration frequencies of a quartz resonator can be significantly different.

 In the proposed sensor, two asynchronous frequencies are simultaneously generated using one amplifier stage and one temperature-sensitive quartz resonator. A necessary phase balance condition for both frequencies is provided by adjusting each of the resonant circuits 3 and 4 to one of the frequencies of the quartz resonator 1 and connecting them to the amplifier amplifier stage using coupling coils 20 and 21 in the collector circuit of the transistor 2. Amplitude balance condition for both frequencies achieved by turning on the output of the resonant circuits 3 and 4 of the limiters 12 and 13 of the voltage and the operation of the transistor 2 on the linear part of the characteristic for each of the generated frequencies, At the same time

the total amplitude of the two generated voltages goes beyond the limits of the linear portion of the characteristic of the amplifying stage of the generator. This achieves the selection in loop 9 of the difference frequency.

As the working frequencies for which the tuning of the resonant circuits 3 and 4 is made, it is advisable to choose the natural oscillation frequencies of the quartz resonator j close to one another. At the same time, the relative sensitivity of the sensor is quite high.

Claims (1)

Invention Formula A frequency temperature sensor containing a temperature-sensitive quartz resonator, including a bipolar transistor in the frequency-drive circuit of an auto-oscillator. Editor N. Stupid Compiled by V. Golubev Tehred. I.Popovich Proofreader O. Lugova Order 3386/40 Circulation 778 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, t. Uzhgorod, st. Project, 4 The first parallel resonant circuit, tuned to one of the frequencies of the mechanical oscillations of the quartz resonator, the mixer and diode-resistive voltage limiters, characterized in that, in order to simplify the design of the sensor, a second parallel resonant circuit tuned to another frequency of mechanical oscillations a quartz resonator; in this case, both the resonant circuits of the circuit are shunted by diode-resistive voltage limiters and connected to the collector circuit of the bipolar transistor with a mixer and through the introduced separation capacitors in series with a quartz resonator - into the positive feedback circuit of the generator between the transistor collector and its base ..