Portable, Wide-Range, Transistorized Gate for Acoustic Research

Abstract

A highly portable, transistorized gate has been developed for use in acoustic research and development. When the gate is used with an oscillator and a power amplifier, electrical pulses are generated. The gate includes controls which permit continuous variation of pulse widths from below 1 msec to above 200 msec at repetition rates from 5 msec to several seconds per pulse. The gate also produces a variable delay pulse for triggering an oscilloscope at any time between the end of one pulse and the start of the next pulse, thus permitting precise study of echoes. Controls are included in the gate circuit to force each pulse to be initiated at the same selected voltage level of the gated signal so that all pulses have identical pulse fronts. Frequencies ranging from 5 cps to over 1 Mc/sec can be gated. The rejection ratio is over 60 db up to 100 kc. The gate has been constructed from readily obtainable, inexpensive components. Several applications for the gate are described.