User Guide

RH-21 Company Confidential
System Module Nokia Customer Care
Page 44  2004 Nokia Corporation. Issue 2 07/2004
Frequency Synthesizers
RH-21 contains three synthesizers — one UHF synthesizer and two VHF synthesizers. The
UHF synthesizer is based on an integrated PLL and external UHF VCO, loop filter, and
VCTCXO. Its main goal is to achieve the channel selection for dual band operations asso-
ciated with dual mode. Due to the RX and TX architecture, this UHF synthesizer is used
for down conversion of the received signal and for final up conversion in transmitter. A
RF input frequency range 135.54 MHz
Conversion gain @
RI=1kohm
23.5 24 24.5 dB
IF AGC gain range (5x6 dB) 30 dB
IF AGC gain step (5 steps) 6 dB
IF AGC gain error relative to
max gain
-0.5 +0.5 dB
AMP2 gain 18 dB
-3dB frequency 21 25 29 kHz
LPF: 4th order Chebysev
LPF gain 0 dB
Corner frequency tuning
range
14 17 kHz
Corner frequency tuning step 1 kHz
Attentuation @ 30 kHz * 24 dB
Attentuation @ 60 kHz * 55 dB
Attentuation @ 120 kHz * 80 dB
Attentuation @ 240 kHz * 60 dB
Attentuation @ >480 kHz * 40 dB
AGC
AGC gain range -6 36** dB
AGC gain range step
7 steps
6dB
AGC gain error relative to
max gain
-0.5 +0.5 dB
Max IF/2nd IF buffer output
level
3 V pp (differen-
tial)
Parameter Minimum
Typical/
Nominal
Maximum Unit/Notes