Sound Velocity Meter Research Articles

Rubidium clock sound velocity meter

A precision sound velocity meter has been made by adding a high stability rubidium oscillator to pulsed ultrasound instrumentation, where its stability and low noise is utilized as a quality time scale and a master clock, to which major timing events such as sound excitation, scope triggering, and time measurements are synchronized. Measuring operations are computer controlled. A reproducibility of ±0.005 m s−1 has been achieved in applications in research chemistry.

Resolution analysis of some types of sound-velocity meters

In a sound-velocity meter the signal-to-noise ratio at the output of the acoustic receiver can be improved by increasing the power of the sounding radiation. But this brings about a growth of uncontrolled change in the state of the medium within the volume being measured (it usually raises the temperature and thus the sound velocity). Therefore in every arrangement there is an optimal power level for the sounding acoustic field at which the destabilizing contribution to a disturbance of the medium's state and to the noise of the active element is minimal.

Low Frequency Underwater Sound Velocity Meter

An underwater sound velocity meter is described which employs an open-end heavy-walled tube for a resonant cavity. The water column is excited into vibration by a sound source near one end, while a hydrophone probe at the tube center registers the pressure amplitude. A sharp resonance (Q=450) permits making relative measurements with an uncertainty of less than 0.2 m/sec when the fundamental mode (f≈570 cps) is used.

Measurement of the Velocity of Sound in the Ocean

An underwater sound velocity meter, which makes continuous recordings of the velocity of sound in the ocean as a function of depth, is described. A phase comparison system of measurement is employed at 500 kilocycles. Several velocity and temperature records are given for comparison.