Frequency-to-Time Converter for Measuring Sound Velocity in Liquids

The measuring converter is based on the principle of tracking the balancing of the separated informative value of the interval probed by an acoustic pulse in the studied medium at a given basic distance by a pulse period divisible by the period of pulses of a frequency-controlled generator. A high accuracy is reached by excluding an inconclusive (spurious) time delay of the acoustic and electric signals in the acoustic converter and electronic operational units. The acoustic base-line distance of the measuring converter is 0.1 m, the measurement range is 1400–1600 m/s, the output signal has a frequency of 140–160 kHz, the absolute basic error is ≤ ±0.015 m/s, and the time to reach a steady-state output signal is ≤0.6 s.