Nokia RH-27 Series Technical Documentation Manual page 30

RH-27
System Module
Power amplifier is 50W/50W module. It does not have own enable/disable control signal,
but it can be enabled by bias voltage and reference bias current signals. The gain window
is +31 to +36dB and linear output power is +30dBm (typical condition) with -28dB ACP.
The nominal efficiency is 40%.
Power Control
For power monitoring, there is a power detector module (PDM) build up from a (dual)
coupler, 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 loose filtering
performance given by duplex filters.
The diode output voltage and NTC voltage are routed to BB A/D converters for power
control purpose. The TX AGC SW takes samples from diode output voltage and compares
that value to target value, and adjust BB I-and Q-signal amplitude and/or RF IC PGA set-
tings to keep power control in balance.
NTC voltage is used for diode temperature compensation and for thermal shut down
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 -0.42dB (max) at cellular band and -0.48dB (max) at PCS
band. Typical values for insertion losses are about -0.2dB. The filtering performance of
diplexer is taken in account in system calculations.
Antenna Circuit
The antenna circuit stands for duplex filters and diplexer. The cellular band duplex filter
is band pass type SAW filter with typical insertion loss about -2.0dB. The PCS band
duplex filter is band stop (for receiver band) type ceramic filter and it's typical insertion
loss is about -1.7dB. Insertion losses of diplexer are -0.45dB and -0.55dB (at maximum)
for cellular and PCS band, typical values being about -0.30dB and -0.35dB.
RF Performance
The output power tuning target for power level 2 after diplexer (or after switch for exter-
nal RF) is +27.3dBm for p/4 DQPSK type of modulation and +24.5dBm for FM type of
modulation. Power levels downwards from PL2 are -4dB below next to highest power
level, PL10 being -4.7dBm (and PL7 +6.5dBm with FM type of modulation). Modulation
accuracy and ACP shall be within limits specified in IS-136/137.
Power
level
2
3
4
Page 30
Table 6: 800 MHz analog TX
RF power at external
Antenna Pad (dBm)
24.8
22.0
18.5
© 2003 Nokia Corporation
CCS Technical Documentation
Tuning target
Testing limits (dB)
tolerant (dB)
+/- 0.25 0.5/-0.5
+/-0.5 +/-2.0
+/-0.5 +/-2.0
Confidential Issue 1 11/2003