A Frequency-to-Time Sound-Velocity Transducer

The transducer described is intended to control the sound velocity in sea water and is based on the principle of the tracking balancing of the probing duration by an acoustic pulse of the studied medium at a given basic distance by the pulse period divisible by the pulse period of the frequency-controlled oscillator. The transducer has a high measurement accuracy, which is achieved by the practical exclusion of a random error component caused by amplitude fluctuations of the received signal as a result of abnormalities of the acoustic transparency of the studied medium caused by various disturbing factors. The acoustic base-line distance of the converter is 0.1 m, the measurement range is 1400–1600 m/s, the output signal is a frequency of 140–160 kHz, the absolute basic error is ±0.035 m/s, and the output signal rise time does not exceed 0.6 s.