Nokia RH-17 Series Troubleshooting - Rf page 61

RH-17
CCS Technical Documentation Troubleshooting — RF
LO: Local Oscillator. This is a CW signal used to mix signals up or down to a different fre-
quency.
PA: Power Amplifier
PDM: Pulse Density Modulation. This is used for control signals. The density of a stream
of digital voltage pulses is varied proportionally to the desired control level, then it is
converted to an analog voltage used as the control signal.
PLL: Phase Locked Loop. Used in Synthesizer circuits to generate an LO.
PPM: part per million
RSSI: Received Signal Strength Indicator.
Nokia Corporation
Issue 1 04/2003 Confidential Page 61