Glossary-6
Glossary
phase-locked loop
A circuit in which an oscillator is kept in phase with a reference, usually
after passing through a frequency divider.
PL
See private-line tone squelch.
PLL
See phase-locked loop.
Power Control IC
The power control IC is intended for closed-loop bias control of power
amplifiers. The device facilitates accurate control of the current
delivered to the power amplifier (PA) via a control voltage.
private-line tone
squelch
A continuous sub-audible tone that is transmitted along with the carrier.
See also DPL.
Programmable
Read-Only Memory
A memory chip on which data can be written only once. Once data has
been written onto a PROM, it remains there forever.
PROM
See Programmable Read-Only Memory.
PTT
See Push-to-Talk.
Push-to-Talk
The switch or button usually located on the left side of the radio which,
when pressed, causes the radio to transmit. When the PTT is released,
the unit returns to receive operation.
radio frequency
The portion of the electromagnetic spectrum between audio sound and
infrared light (approximately 10 kHz to 10 GHz).
radio frequency
power amplifier
Amplifier having one or more active devices to amplify radio signals.
RAM
See random access memory.
random access
memory
A type of computer memory that can be accessed randomly; that is, any
byte of memory can be accessed without touching the preceding bytes.
read-only memory
A type of computer memory on which data has been prerecorded. Once
data has been written onto a ROM chip, it cannot be removed and can
only be read.
real-time clock
A module that keeps track of elapsed time even when a computer is
turned off.
receiver
Electronic device that amplifies RF signals. A receiver separates the
audio signal from the RF carrier, amplifies it, and converts it back to the
original sound waves.
registers
Short-term data-storage circuits within the microcontroller unit or
programmable logic IC.
repeater
Remote transmit/receive facility that re-transmits received signals in
order to improve communications range and coverage (conventional
operation).
Term
Definition
Summary of Contents for Astro APX 3000
Page 1: ...APXTM TWO WAY RADIOS APX 3000 DETAILED SERVICE MANUAL ...
Page 2: ......
Page 4: ...Notes ...
Page 6: ...vi Document History Notes ...
Page 10: ...x Table of Contents Notes ...
Page 12: ...xii List of Tables Notes ...
Page 18: ...xviii List of Figures Notes ...
Page 22: ...xxii CommercialWarranty Notes ...
Page 46: ...3 20 Theory of Operation Main Board Notes ...
Page 84: ...3 58 Theory of Operation Bluetooth Notes ...
Page 208: ...6 64 Troubleshooting Waveforms LF CW on Spectrum Analyzer Notes ...
Page 222: ...7 14 Troubleshooting Tables List of Board and IC Signals Notes ...
Page 282: ...8 60 Schematics Boards Overlays and Parts Lists Main Board Block UHF1 84012513001_A Notes ...
Page 390: ...8 168 Schematics Boards Overlays and Parts Lists Main Board Block VHF 84012512001_A Notes ...
Page 456: ...9 8 Debugging Fixture Powering up Covert Board Notes ...
Page 468: ...Glossary 10 Glossary Notes ...
Page 472: ...Index 4 Index Notes ...
Page 473: ......