User Guide

RH-17
System Module CCS Technical Documentation
Page 30 Nokia Corporation Confidential Issue 1 04/2003
with a PDM control voltage.
The transmitter chain utilizes smart power techniques and only the required circuits are
powered at the appropriate times. In order to save energy in puncture mode, when there
is no speech activity during a call, the driver and power amplifiers and the Robin IC are
switched ON and OFF rapidly. These units also are in the OFF state when the transmitter
is in standby. The ON/OFF switch commands are issued by a Digital ASIC (UPP). The UPP’s
PDM controls a current mirror in Robin that provides the PA reference current. Switching
each reference current ON/OFF switches each PA ON/OFF. The VHF synthesizer and power
detector circuits are left on during the puncture mode.
Synthesizer
Refer to Figure 6 for a block diagram that illustrates all three synthesizers and how they
interconnect in the system.