User's Manual

October 14, 2003 6881094C31-C
Glossary-4
frequency
generation unit
This unit generates ultra-stable, low-phase noise master clock and other
derived synchronization clocks that are distributed throughout the
communication network.
General-Purpose
Input/Output
Pins whose function is programmable.
GPIO See General-Purpose Input/Output.
host code Object code executed by the host processor in an ASTRO subscriber
radio. The host is responsible for control-oriented tasks such as
decoding and responding to user inputs.
IC See integrated circuit.
IF Intermediate Frequency.
IMBE A sub-band, voice-encoding algorithm used in ASTRO digital voice.
inbound signaling
word
Data transmitted on the control channel from a subscriber unit to the
central control unit.
integrated circuit An assembly of interconnected components on a small semiconductor
chip, usually made of silicon. One chip can contain millions of
microscopic components and perform many functions.
ISW See inbound signaling word.
keep-alive mode A software-controlled operational mode in which power for the radio
remains on after the On/Off/volume control knob is turned off to allow
the microcontroller unit to complete its power-down sequence. Then,
the radio completely powers off.
key-variable loader A device used to load encryption keys into a radio.
kHz See kilohertz.
kilohertz One thousand cycles per second. Used especially as a radio-frequency
unit.
KVL See key-variable loader.
LCD See liquid-crystal display.
LED See light emitting diode.
light emitting diode An electronic device that lights up when electricity is passed through it.
liquid-crystal display An LCD uses two sheets of polarizing material with a liquid-crystal
solution between them. An electric current passed through the liquid
causes the crystals to align so that light cannot pass through them.
LO Local oscillator.
Term Definition