Sound at frequencies above the audible range, namely above 20 kHz, audible only to various non-human species. Because of its very short WAVELENGTH in the megahertz range, ultrasound is used as a safe alternative to X-ray photography in medical diagnosis. Ultrasound scanning is sometimes called sonography.
An adjective describing any process involving the transfer of a SIGNAL from acoustic to electrical form, or vice versa. Most commonly, TRANSDUCERs such as the MICROPHONE or LOUDSPEAKER are examples of this process.
If two TONEs are about 15 Hertz or less apart, INTERFERENCE will result from their similar though not exactly identical frequencies. Gradually they will move out of PHASE until at 180
A recent development where, in contrast to the conventional analog TAPE RECORDER, the audio SIGNAL is sampled within a set of pre-defined limits. It is thus the reciprocal process to that described as digital SOUND SYNTHESIS. Digital sampling is also used is some digital SOUND SYNTHESIZERs.