JPS6328257B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature measurement device that wirelessly measures the temperature of a temperature measurement target located at a distance.

Conventionally, temperature measurement devices have been proposed that measure the temperature of the temperature-measured part by sending a sweep pulse to a temperature-sensitive resonant circuit and counting the frequency of the reflected wave. The disadvantage is that it requires large-scale equipment such as processing equipment, making the equipment expensive.

The present invention relates to a temperature measuring device that eliminates the above-mentioned drawbacks.

An embodiment of the temperature measuring device of the present invention will be described below with reference to the drawings.

In Figure 1, 1 is VCO (Voltage
Controlled Cscillator) The second voltage applied to circuit 2
This is a sawtooth voltage generation circuit as shown in FIG. A sweep wave up to is generated with a period t. 3 is an intermittent signal transmitting circuit, as described above.
A passing pulse as shown in FIG. 2C is applied to the sweep wave from the VCO circuit 2, and an intermittent pulse as shown in FIG. 2D is transmitted to the temperature sensitive resonant circuit 4 set in the temperature measuring section. In the temperature-sensitive resonant circuit 4, when a pulse of a resonance frequency fo determined by the temperature of the temperature-sensitive crystal oscillator or a frequency close to it arrives, it resonates and a reflected wave as shown in FIG. 2E is sent to a time-selective receiving circuit. Send a call to 5. As shown in FIG. 2F, the time selection receiving circuit 5 selects t from the passing pulse based on the detection pulse (FIG. 2F) whose phase is shifted by a fixed time t' with respect to the passing pulse of the intermittent signal transmitting circuit 3. 'Only the delayed time point is received and applied to the voltage detection circuit 6. The voltage detection circuit 6 generates a resonant reflected wave as shown in FIG.
The voltage v of the sawtooth voltage generation circuit 1 applied to the VCO circuit 2 at the time when fo is detected is detected. In this case, although there is a difference from the voltage Vo at the time of oscillation, it can be corrected in advance. The voltage detected by the voltage detection circuit is applied to the processing circuit 7, and the processing circuit 7 displays the temperature and operates the device to measure the temperature of the temperature-measured section.

In the above configuration, the sweep wave generated from the VCO circuit 2 may be generated in stages, the waveform may be checked by the voltage detection circuit 6, and the temperature sensing element is not limited to crystal but may also be made of lithium niobate. It is also possible to use a surface acoustic wave oscillator such as a surface acoustic wave oscillator, ferrite, or a magnetic capacitor.Also, in the above embodiment, a sweep wave is oscillated in a pulse form and its delayed reflected wave is detected, but a continuous sweep wave oscillator may be used. The same effect can be obtained even if the dip phenomenon, resonance phenomenon, phase shift phenomenon, etc. at the resonance point are detected by oscillating the signal.

The temperature measuring device of the present invention has the above-described configuration, and there is no need to count the frequency of the sweep wave or judge the reflected waveform, and the device can be significantly simplified, providing an inexpensive device. can do.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of one embodiment of the temperature measuring device of the present invention, and FIG. 2 is a waveform diagram of each part of FIG. 1. In the drawing, 4 indicates a temperature-sensitive resonant circuit.

Claims (1)

[Claims] 1. A sawtooth voltage generation circuit, a circuit that oscillates a sweep wave using the sawtooth voltage, and an intermittent signal generation circuit that intermittently oscillates the sweep wave based on passing pulses of a constant period. , a temperature-sensitive resonant circuit that is set in the temperature-measured section and resonates when a pulse of a resonance frequency determined by the temperature of the temperature-measured section or a frequency close to the resonance frequency arrives from the intermittent signal generation circuit; and this temperature-sensitive resonant circuit. means for detecting the reflected wave of by a detection pulse whose phase is shifted by a certain period of time with respect to the passing pulse; and detecting resonance based on the output of the detection means;
A temperature measurement device comprising: a measurement circuit that measures temperature using the sawtooth voltage at the time of this detection.