SU901841A1 - Temperature pickup - Google Patents

Description

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The invention relates to thermometry and can be used in radiotelemetric temperature measurements.

Devices are known for radiotelemetric temperature measurements in which thermistors or semiconductor devices L1 J are used as sensing elements.

In such devices, the output signal has low power and for amplification and transmission over the radio channel, transducer amplifiers are inserted into the devices, from the output of which the amplified signal goes to the modulator, where the transmitter frequency signal is modulated. At the same time, the accuracy of temperature measurement depends not only on the change in the resistance value of the sensitive element, but also on the stability of the parameters of the amplifier modulator and transmitter when the temperature changes.

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the environment. On the other hand, measures to stabilize the parameters complicate the device, increase its cost and do not allow to reduce the overall weight characteristics.

The purpose of the invention is to simplify the device of a telemetric temperature sensor and to obtain a powerful telemetric signal directly from the sensor.

The goal is achieved by using a transistor supergenerative receiver as a telemetric temperature sensor around the environment.

1 shows a diagram of a telemetric temperature sensor; figure 2 - the curve of the dependence of the frequency of superization from temperature.

The superregenerative receiver includes an active element, for example, a transistor 1, an oscillating circuit consisting of inductance 2 and a capacitor 3, an auto 39 circuit

displacement (resistor 4 n capacitor 5) and receiving antenna 6,

The time constant of the auto-bias circuit is chosen to be longer than the time constant of the circuit. In this case, in the absence of a signal in the superregenerative receiver, high-frequency oscillations are formed, the period of which is proportional to the time constant of the auto-sensing circuit. There is an auto-supercirculation mode.

In the study of stability, the operation of a superregenerative receiver on a transistor in a wide temperature range was found to be strong, the dependence of the frequency of auto-supervision on temperature. This can be explained by the change in the collector current of transistor I with temperature. With a decrease in temperature, the collector current decreases, with increasing temperature increases. For this reason, the capacitor 5 is charged before the oscillation stall voltage is slower or faster. Consequently, the frequency of the flashes decreases or increases with temperature.

From the graph (Fig. 2), it follows that with increasing ambient temperature, the frequency of radio pulses increases, and decreases with decreasing temperature.

If the receiver registers the frequency of the following

diodes from the power-synchronous receiver on the transistor, it is possible by graph (FIG. 2 to know the ambient temperature in which the receiver is located. Thus, the super-regenerative receiver on the transistor performs the role of a telemetric temperature sensor, combining the functions of measurement, amplification, conversion and transmission information about the temperature over the air.

The use of a transistor superregenerative receiver for radio-telemetry of the ambient temperature has advantages, since this sensor is very simple in structure, has a minimum of radio radio elements and is cheap compared to the known ones.

Claims (1)

1.Gerashchenko O.A. and others. Thermal and temperature measurements. -K., Naukova Dumka, 1965, p. 49-153. v