Appendix G 197
Glossary of Terms
AGC Automatic Gain Control (or Automatic Volume Control). A feature on
a hearing aid that automatically adjusts the gain, depending either on
the input level (AGC-I) or the output level (AGC-O). Also known as
“Compression.”
AIDED The response of a hearing aid in place on the ear. (Also called “In-situ
RESPONSE Response.”) Subtract the “Unaided Response” from the “Aided
Response” to get the Insertion Gain Response. When the Aided
Response is measured in a real ear (as opposed to a manikin), it is
called the “Real Ear Aided Response” (or “REAR”).
AMBIENT The environmental sounds in a testing area.
NOISE
ANECHOIC A room with little sound reverberation; a room constructed to be
CHAMBER acoustically absorptive.
AMPLITUDE A measure of the magnitude of a signal.
ANSI American National Standards Institute. A national organization that
determines standards for testing equipment. A section number and date
(year) following the initials “ANSI,” designate the standard referred to.
ARTIFACT A false reading.
ASP Automatic Signal Processing. A feature on a hearing aid intended
to overcome the effects of background noise, making it easier to
understand speech when noise is present. The term ASP is not
standardized, and may refer to various forms of signal processing.
Usually, however, ASP refers to a reduction in low-frequency gain in
the presence of ongoing background noise.
AVG Short for Averaging. An option on the 7000 Test System that uses three
pure tones and averages them for the screen display.
BATTERY A battery simulator that conforms to the size and shape of a battery
SUBSTITUTION used in a hearing aid. It connects to the Battery Voltage Supply,
PILL providing the proper voltage to the hearing aid.
BERGER A prescription formula developed by Kenneth W. Berger).
BIAS FREQUENCY The background frequency, acting as noise, when using the Digital-
Speech-in-Noise test.
BIAS AMPL The amplitude of the background frequency used in the Digital-
Speech–in-Noise test.
