Application of Time-Delay Spectrometry for Calibration of Ultrasonic Transducers

Abstract

Time-delay spectrometry (TDS) is a technique that can conveniently be used for calibration and performance evaluation of piezoelectric electroacoustic transducers. The main emphasis is an experimental evaluation of the TDS technique, through actual transducer calibrations and through simulation experiments. The TDS concept is introduced through a theoretical analysis of the TDS technique. The experimental evaluation is carried out using specially designed measurement methods and instrumentation. The measurement setup employs a spectrum analyzer as the central analog signal processing unit. The optimal performance of the TDS measurement system is analyzed in terms of relevant instrumentation parameters, i.e., intermediate frequency (IF) filter bandwidth, sweep time, sweep rate, frequency range, and signal-to-noise ratio. The advantages and disadvantages of the time-delay spectrometry technique, including practical performance limitations, are discussed, along with the measurement uncertainties of the method. It is shown that the TDS technique in the frequency range covering both underwater acoustics and medical ultrasonics applications offers a viable alternative to other calibration techniques, such as those based on a gated burst measurement system. © 1988 IEEE