6816812H01 March 23, 2006
Glossary-3
firmware Code executed by an embedded processor such as the Host or DSP in
a subscriber radio. This type of code is typically resident in non-volatile
memory and as such is more difficult to change than code executed
from RAM.
FGU See frequency generation unit.
flash A non-volatile memory device similar to an EEPROM. Flash memory
can be erased and reprogrammed in blocks instead of one byte at a
time.
frequency Number of times a complete electromagnetic-wave cycle occurs in a
fixed unit of time (usually one second).
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.
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.
kHz See kilohertz.
kilohertz One thousand cycles per second. Used especially as a radio-frequency
unit.
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.
Term Definition
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