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A
• Accessory
(position) - Refers to the position of
the key in the ignition switch; a wire
showing 12 Volts (+) when in this position.
• Acoustic
Absorption - The sound deadening
properties of any substance, measured in
Sabine units. One Sabine is equal to the
absorption of 1 square foot of surface which
will absorb all incident energy.
• Acoustic
Feedback - A squealing sound when the
output of an audio circuit is fed back in
phase into the circuit's input.
• Acoustical
Energy - Energy consisting of
fluctuation waves of pressure called sound
waves.
• Acoustics
- The study of sound. The science of
production, effects, and transmission of
sound waves through various mediums and the
effects of absorption, diffraction,
interference, reflection, and refraction.
• Active Arming
- A method for arming a security system that
requires some action such as pressing a
button on a remote transmitter or entering a
code on a keypad
• Active
Display - A step-up display feature that
generates animated patterns for both segment
and dot matrix LCDs that precede the
sequential display of information such as
clock, Custom File titles and radio station
frequencies.
• Aftermarket-
Equipment that can be added to a vehicle.
• Air Gap -
The space between the top plate and the pole
piece. This is where the voice coil sits.
• Aliasing
Noise - The result of the sampling
frequency not being at least double the
highest analog frequency during the digital
encoding of an analog signal.
•
Alternate-Channel Selectivity - A
measurement of a tuner's ability to select
one radio station's signal and reject the
signal of another radio station two channels
(0.4 MHz) away. Measured in decibels, the
higher the number the better.
• Alternating
Current (AC) - An electric current that
reverses direction at regular intervals.
Measured in Volts AC at Hertz, example: 110
volts AC 60 Hz.
• Alternator
- A device that is turned by a motor to
produce AC voltage, which is then rectified
(turned into DC) and used to supply voltage
to the vehicle's electrical system.
• Alternator
Whine - A whining that is heard when the
RPMs of an engine increase. The noise is
usually the result of a voltage differential
created by more than one ground path or a
poor ground path (ground loop).
• American Wire
Gauge (AWG) - A standard of the
dimensional characteristics of wire used to
conduct electrical current or signals. AWG
is identical to the Brown and Sharpe (B & S)
wire gauge.
• Ammeter -
An instrument that measures the magnitude of
an electric current in amperes.
• Ampere (amp)
- A unit that defines the rate of flow
of electricity (current) in a circuit.
• Amplification
- The increase in signal level, amplitude or
magnitude.
• Amplifier
- A device which increases the level of a
signal by increasing the current or voltage.
May also be used to isolate or control a
signal and even decrease the level as in a
line output converter.
• Amplifier
Power - An amplifier designed for
driving loudspeakers and having a higher
power output than a line amplifier or
preamplifier.
• Amplitude
- The maximum value of a periodically
varying quantity.
• Amplitude
Modulation (AM) - The encoding of a
carrier wave by variation of its amplitude
in accordance with an input signal. AM
Stereo
• Analog -
A way to represent data by means of
continuously variable quantities. A control
or circuit which continuously changes the
level of a signal in direct relationship to
the control setting. An electrical signal
whose frequency and level vary continuously
in direct relationship to the original
acoustical sound waves. (Something that is
analogous).
• Analog to
Digital Converter (ADC) - A circuit that
converts an analog signal into a digital
signal. With a continuous input signal the
ADC will check the signal several time per
second (sampling), assign values to the
samples and represent it as a binary number
(quantization and encoding).
• Analogous
- Alike in certain ways. Similar in function
but not in origin or structure.
• Anode -
The electrically positive pole of an
electronic device such as a semiconductor. A
diode, for instance, has a positive and a
negative pole; these are known as the anode
and the cathode
• Antenna -
An apparatus used for sending and receiving
radio waves, usually constructed of metal.
• Antenna
Trimmer - An adjustment found on analog
radios used to maximize AM reception.
Turning this trimmer to the point where the
sound is the loudest increases the sets
signal to noise ratio optimizing
performance.
• Attenuator
- A device to decrease or increase the
strength of a signal.
• Auto Eject
- Feature of a cassette player that ejects
the tape when it has finished playing one
side.
• Auto Loud
- Automatically provides low frequency boost
for listening at low levels.
• Auto Memory
- A tuner feature that automatically
finds the strongest stations in the local
area, and places them in preset memories.
• Auto Replay
- Feature of a cassette player that
automatically rewinds a tape when it has
reached the end of one side, then begins to
replay.
• Auto Reverse
- Feature of a cassette player that
automatically plays the reverse side of a
tape when one side has reached the end.
• Auto Stop
- Feature of a cassette player that
automatically shuts off power when a tape
has reached the end of either side in any
mode.
• Automatic
Gain Control (AGC) - A circuit that
continuously adjusts the recording amplifier
gain to maintain a relatively constant
recording level.
• Azimuth - The perpendicular
alignment of the tape to the head of a tape
player / recorder.
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