Title :
Calibration of vibration pickups at low ultrasonic frequencies
Author_Institution :
Nat. Inst. of Stand. & Technol., Gaithersburg, MD, USA
Abstract :
The requirements for and peculiarities of vibration measurements at low ultrasonic frequencies are discussed in the context of existing practice and needs. A method for calibrating vibration pickups in the frequency range 10-30 kHz is described and illustrated with examples. The method requires two types of measurements: the driving-point impedance of the vibration exciter loaded by the test pickup and a known mass, and the voltage ratio of pickup output to driver input. The calibration formula is based on the Moebius transformation of two-port impedances and the product relationship of cascaded systems. The sensitivity of a pickup, in both magnitude and phase, is determined from three sets of observations, using calibrated masses and a programmable impedance/gain analyzer
Keywords :
calibration; ultrasonic measurement; Moebius transformation; calibrated masses; cascaded systems; driving-point impedance; low ultrasonic frequencies; two-port impedances; vibration exciter; vibration measurements; vibration pickups; Acoustic measurements; Calibration; Frequency measurement; Instruments; Mechanical variables measurement; Particle measurements; Time measurement; Ultrasonic variables measurement; Vibration measurement; Voltage;
Conference_Titel :
Ultrasonics Symposium, 1989. Proceedings., IEEE 1989
Conference_Location :
Montreal, Que.
DOI :
10.1109/ULTSYM.1989.67096
