A digital hardware correlation system for fast ultrasonic data acquisition in peak power limited applications

The theoretical and experimental evaluation of a digital hardware correlation system for low-power ultrasonic applications is presented. The system, which incorporates dual Golay code matched filtering, is capable of 20-MHz processing rates with a signal-to-noise-ratio enhancement (SNRE) of 23 dB over a conventional pulse-echo system operating at the same peak power levels. The effects of digitization have been investigated, and a TTL (transistor transistor logic)-based hardware correlator has been developed. For many applications, low-voltage driving followed by differential detection is sufficient, permitting the system to be used in a number of power-limited environments. Sample tests conducted on three different transducers have demonstrated that the system is operational over a wide variety of probe configurations.