Ashly Power Amplifiers FET-200 - Manual (Page 10)

DEFINITION OF TER^iS AS USED IN THIS MANUAL
ACTIVE
Electronic circuits which use devices such as transistors and integrated
circuits, and which are capable of voltage and power gain as well as
loss. Circuits using only resistors, capacitors, transformers, etc., are
referred to as passive.
AMPLITUDE
The voltage level of a signal. May be measured in volts or decibels.
Generally corresponds to the volume or intensity of an audio signal.
BALAilCED
A 3-wire circuit arrangement in which two conductors are designated as
signal lines (+ and -), and the third is a shield and chassis ground. The
signal lines are of opposite polarity at any given moment, and are of
equal potential with respect to ground, balanced input amplifiers are
used on ail Ashly SC series products^to improve hum and noise rejection.
Jumpering signal minus (-) to ground provides an unbalanced input.
BREATHING
A usually undesirable fluctuation of background noise resulting from
compressor action. (Also called "Pumping.")
BUTTERWORTH
The name of a particular filter response shape. The response is
essentially "flat" within the pass-band, is 3dB down at the cutoff
frequency, and continues to attenuate at a constant slope. Also called a
"maximally flat" or "critically damped" filter shape, it is very popular
for crossovers and shelving filters.
CENTER FREQUENCY
The frequency (or pitch) at which a filter is most effective. In a
parametric equalizer, it refers to the frequency where a particular
boost/cut control has maximum effect.
COMPRESSOR
An amplifier wiiich reduces its gain as its input is increased
predetermined "threshold."
beyond a
DAMPING
A
dB
force which opposes the tendency of a system to oscillate.
A unit by which audio levels can be COMPARED. Often thoroughly
misunderstood are the concepts that decibels represent the level of a
signal compared to some reference level (15 dB cut means a certain level
less than a previous level ---- the absolute level of the signal need not
be known), and that decibels are a logarithmic unit. Some handy numbers
to remember when dealing with decibels;
+3 dB = Double Power
+6 dB = Double Amplitude,
Quadruple Power
+10 dB = lOX Power
+20 dB = lOX Amplitude, lOOX Power