User Guide

RH-21 Company Confidential
System Module Nokia Customer Care
Page 46  2004 Nokia Corporation. Issue 2 07/2004
After the Safari, the balanced RF-signal is single-ended in 1:1 balun and then filtered in
SAW filter. The typical insertion loss is about –4.0 dB, and maximum less than –5.7 dB.
This filter has a relatively high pass band ripple of about 1.0-1.5 dB, the largest insertion
being at the high end of the band. The input and return losses are about –10 dB.
Power amplifier is 50Ω/50Ω module. It does not have its own enable/disable control sig-
nal, but it can be enabled by bias voltage and reference bias current signals. The gain
window is +31 to +36 dB and linear output power is +30 dBm (typical condition) with
-28 dB ACP. The nominal efficiency is 40 percent.
Power Control
For power monitoring, there is a power detector module (PDM) built from a (dual)cou-
pler, a biased diode detector, and an NTC resistor. RF signals from both bands are routed
via this PDM. The RF isolation between couplers is sufficient not to lose filtering perfor-
mance given by duplex filters.
The diode output voltage and NTC voltage are routed to BB A/D converters for power
control purposes. The TX AGC SW takes samples from diode output voltage and compares
those values to target value, and adjusts BB I-and Q-signal amplitude and/or Safari PGA
settings to keep power control in balance.
NTC voltage is used for diode temperature compensation and for thermal shutdown
when radio board’s temperature exceeds +85° C.
False TX indication is based on detected power measurement when carrier is not on.
The insertion loss of coupler is –0.42 dB (max) at cellular band and –0.48 dB (max) at
PCS band. Typical values for insertion losses are about –0.2 dB. The filtering performance
of diplexer is taken into account in system calculations.
Signal levels
Power Level
TDMA
Target
AMPS
Target
PL2 27.2 24.4
PL3 23.3 21.1
PL4 19.3 17.8
PL5 15.3 14.5
PL6 11.3 10.5
PL7 7.3 6.5
PL8 3.2 3.2
PL9 -0.9 -0.9
PL10 -5.3 -5.3