Fast tracking device and method for resonant frequency of mechanical ultrasonic transducer

Abstract

The present invention belongs to the field of ultrasonic technologies and relates to an apparatus and method for quickly tracking the mechanical resonance frequency of a transducer. The fast trackingdevice for the mechanical resonance frequency of the ultrasonic transducer of the invention comprises a piezoelectric ultrasonic transducer, a voltage sensor, a current sensor, a matching inductor, aD-class power amplifier, an arbitrary waveform generator DDS, a microprocessor, a phase detecting circuit, a peak detecting circuit and an amplifying and filtering circuit; the microprocessor controlsthe DDS to output sinusoidal driving signals; the piezoelectric ultrasonic transducer is driven through the D-class power amplifier; at the same time, the current sensor collects current flowing through the piezoelectric ultrasonic transducer; the voltage sensor collects the voltage of the two ends of the piezoelectric ultrasonic transducer; noise and harmonic wave filtering and amplification areperformed on two paths of sampling signals through the amplifying and filtering circuit; and the magnitude of the complex admittance of the transducer is calculated, and the resonant state of the transducer is judged. Thereby, the mechanical resonance frequency of the transducer can be obtained through demodulation. The apparatus and method of the invention are mainly applied to ultrasonic detection conditions.

Description

technical field

[0001] The invention relates to the field of ultrasonic technology, in particular to a fast tracking device and method for the mechanical resonance frequency of an ultrasonic transducer. Background technique

[0002] Piezoelectric ultrasonic transducers are widely used in the field of ultrasonic technology due to their advantages of low cost, small size, and high power. Its key technology is to track the frequency of the ultrasonic transducer to obtain higher output efficiency. The piezoelectric ultrasonic transducer itself has multiple characteristic frequencies, including resonant frequency, anti-resonant frequency, series resonant frequency, parallel resonant frequency, etc. The series resonant frequency is the mechanical resonant frequency of the transducer, which has the largest power output and the smallest Calorific value is the best working frequency. Because the resonant frequency and the series resonant frequency are close and easy to track, many ...

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