SU149927A1 - Calibration method of piezoelectric vibration receivers - Google Patents

Description

Known methods of calibration of the piezoelectric vibration receivers based on the reciprocity principle with a reversible vibration transducer mechanically coupled to a graduated receiver, have significant drawbacks:

a) a complicated cumbersome apparatus is required for calibration;

b) the calibration is carried out as a result of a large number (60-90) of measurements with permutations of transducers;

c) the calibration is carried out using the reference mass, which narrows the frequency range of measurements;

d) the calculation of the sensitivity values at each frequency is carried out analytically and requires a considerable amount of time.

The main feature of the proposed method consists in connecting an auxiliary vibration sensor, a calibrated vibration receiver and a reversible vibration sensor, into one unit and switching these elements in the measurement process between themselves, which makes it possible to refuse the use of the reference mass, to calibrate without rearranging the converters, to extend the calibration range, automate the measurement process.

FIG. 1 shows a diagram of an apparatus for implementing said method for calibrating piezoelectric vibration receivers; in fig. 2-block diagram of the automatic computing system.

A device for calibrating piezoelectric vibration receivers consists of an auxiliary vibration sensor /, made in the form of a flat disk made of piezoelectric ceramics, to which a reversible vibration sensor 2 is attached on one side, and on the other a graduated vibration receiver 3.

No. 149927-2 -

The vibration sensor 2, used as a reversible transducer, is designed as a compact compact broadband piezoelectric vibration receiver. The auxiliary vibration sensor /, the emitter 2 and the graduated vibration receiver i for the GROSS | 1rovki are connected (in line, as shown in Fig. 1.

To carry out the calibration of the vibration receiver 3. Three steps are carried out - Actual measurements (four measurements at each frequency) and one mechanical measurement (weighing vibration sensors 1 and 2 and calibrated vibration receiver 3).

During the first etade of measurements, the auxiliary vibration sensor / is excited by the electric oscillator 4. The output voltage of the calibrated vibration receiver 3 and the voltage of the reversible vibration sensor 2 are measured.

In the second and third measurement stages, a reversible vibration sensor 2 is excited by an electrical oscillator 4. The voltage of the calibrated vibration receiver 3 is measured and the current flowing through the reversible vibration sensor to 2. With electrical switching, all four values measured during calibration are applied to the counting key. a circuit that performs the mathematical operation of multiplying, dividing and extracting the root Of the values obtained.

The block diagram of the automatic counting unit (Fig. 2) consists of a logarithmic amplifier 5, an algebraic adder b and a level recorder 7, which by means of switches 8, 9 and 10, operating synchronously, are included in the circuit of the electrical oscillator 4 and the calibration device piezoelectric vibration receivers //.

The switches 8, 9 and 10 can be made in the form of a relay circuit or device of the collector type or in the form of a lamp contactless switching device. The switching cycle periodically repeats at a rate of about a fraction of a second (for example, with a network frequency).

Switching switches 8 and 9 ensures that all stages of the measurement are carried out consistently. In order to obtain a continuous frequency response of the vibration receiver, multiply and extract carnage: the measured voltage values are performed by logarithmizing the sequence of signals in a logarithmic amplifier and supplying them with the help of a synchronous switch 10 to four separate channels connected according to an algebraic adder 6.

The output of the algebraic adder is connected to the input of a level 7 recorder equipped with a linear potentiometer. For the calibration of the tape recorder levels, the electrical calibration of the lower and upper levels of the filing mains to the input of the logarithmic amplifier 5 is performed through switches 8, 9 and 10 electrical signals having known relations among themselves.

The described method of calibration of piezoelectric vibration receivers allows to significantly expand the range of calibration, increase the speed of calibration of the vibration receiver, and automate the measurement process.

PREd. M e invented and

The method of calibration of piezoelectric vibration receivers, based on the disposition of the calibrated receiver, connected