SU418812A1 - DEVICE FOR MEASUREMENT OF EQUIVALENT DYNAMIC PARAMETERS OF PIEZOELECTRIC RESONATORS - Google Patents

Description

one

A device is known for measuring equivalent dynamic parameters of piezoelectric resonators containing, in series, its rectangular pulse generator, shock excitation generator with the resonator under test, a detector, a two-threshold trigger circuit, and an indicator.

The non-linearity of the characteristic of an amplitude detector is the cause of a significant measurement error.

The purpose of the invention is to improve the measurement accuracy.

The proposed device is characterized in that between the output of the trigger circuit and the input of the indicator, there are connected in series a symmetric trigger and integrate, a / C-circuit.

The invention is illustrated in block diagram form.

A device for measuring equivalent dynamic parameters of piezoelectric resonators contains a series-connected rectangular impulse generator 1, a shock excitation generator 2 with the test resonator, a detector 3, a two-threshold trigger circuit 4, a symmetric trigger 5, integrate; the JRC-center 6 and the indicator 7. Symmetric trigger 5 and integrate, while C-center 6 is connected between the output of the opening circuit 4 and the input of the indicator 7.

2

The generator of shock excitation operates in the mode of continuous generation, which is created by supplying control of their rectangular pulses from the output of the generator of rectangular pulses 1, and the follow-on period of these pulses is selected from the condition of multiple exceeding the maximally constant constant time, which is free-flowing, their oscillations piezoelectric resonator.

The exponential bending of the free-flowing oscillations of the piezoelectric resonator is extracted by detector 3. The voltage from the detector output goes to the input of a two-threshold trigger circuit 4 with trip thresholds t and i and IJ-2. The pulses from the output of the two-threshold trigger circuit control a symmetric trigger 5, and the duration of the output trigger pulses corresponds to the decay time of the exponential envelope from the level t / i to the level u. Square pulses from the output of trigger 5 are fed to an integrating / C-circuit with variable and known parameters. The magnitude of the charge to which the capacitor of the integrating circuit is charged during the pulse duration from the output of the trigger 5 is recorded by the indicator 7. The sensitivity of the indicator 7 is chosen such that its reading is possible only in case of equality or a predetermined multiplicity of the time envelope of the free oscillations of the subject resonator and integrating / Ledeni.

Equivalent dynamic parameters of piezoelectric resonators are measured as follows.

A piezoelectric resonator is introduced into the shock excitation generator 2, and the time constant of the integrating 7 C-circuit changes until indicator 7 shows the reading value. At this moment, the value of the time constant of the integrating U C-circuit gives a constant of the decay time of the free oscillations of the test piezoelectric resonator.

Subject invention

A device for measuring equivalent dynamic parameters of piezoelectric resonators containing series-connected square pulse generator, shock excitation generator with the resonator under test, detector, two-threshold trigger circuit and indicator, characterized in that, in order to improve measurement accuracy, between the output of the trigger circuit and the indicator input included in series are connected symmetric trigger and integrating KS circuit.