We produce this special reference sound source for air ultrasound to meet the needs of manufacturers of ultrasound detectors such as leak detectors and motion sensors. This RSS 101U will produce calibrated intensity from 10 kHz through 100 kHz. It provides a steady and reliable ultrasound field that is also useful for calibration of ultrasound microphones by the substitution (comparison) method of ANSI WG1.26 (draft).
A distinct advantage of substitution (comparison) calibration of microphones in this RSS101U broad band sound field is that the broad band sound, even just 1 kHz wide, eliminates the “Ripple” or Scalloping” effect of pure tone sound waves spawned by nearby jigs and fixtures.
This RSS 101U produces a cylindrical source of ultrasound 3 inches (75mm) high and 6″ (150mm) wide, Omnidirectional in all azimuth directions. Test microphones are usually positioned 1/2m from the source. There, in the 10-20 kHz frequency range, will be found broad band ultrasound having a sound pressure level of about 60 dB re 20 micropascals, per kHz of bandwidth. This sound field diminishes to about 50 dB in a one kHz band at 50 kHz, to 34 dB in a one kHz band at 100 kHz. It operated on 115vac, 60 Hz. It may operate at 50 Hz with a lower sound power emission. Physical size and weight is the same as our RSS101.