User Guide

Nokia Customer Care System Module
Company Confidential RH-21
Issue 2 07/2004  2004 Nokia Corporation. Page 39
Main Technical Characteristics
RF Frequency Plan
The RH-21 frequency plan is shown in the following figure. A 19.44 MHz VCTCXO is used
for UHF and VHF PLLs and as a baseband clock signal. All RF locals are generated in PLLs.
Figure 8: RF Frequency Block Plan
The RX intermediate frequency is the same on both operating bands. Due to the AMPS
mode simultaneous reception and transmission, TX and RX IF frequencies are exactly
45 MHz apart from each other. RXIF is 135.54 MHz and TXIF 180.54MHz. The RXIF fre-
quency is set so that it is not a multiple of either of the VHF's comparison frequency
(120 k). The digital-only operation on highband allows a free selection of the TX IF fre-
quency, since separate TXIF filters are implemented. Hence, the highband TX IF frequency
is freely fixed to 181.8MHz due to the best possible spurious signal filtering. Therefore,
the UHF frequency needs to be changed according to TX and RX slots in TDMA1900 oper-
ation.
F
2
PLL
PLL
F
2
PLL
F
2
UHF
TDMA800 2009.16 MHz 2059.02 MHz
TDMA1900 RX: 2065.59 MHz 2125.53 MHz
TDMA1900 TX: 2031.81 MHz 2091.75 MHz
Rx Channel Centre Frequencies
TDMA1900 1930.05...1989.99 MHz
Rx Channel Centre Frequencies
TDMA800 869.04...893.97 MHz
Tx channel centre frequencies
TDMA800 824.01...848.97 MHz
Tx channel centre frequencies
TDMA1900 1850.01...1909.95 MHz
Tx VHF
TDMA800: 361.08 MHz
TDMA1900: 363.60 MHz
Tx IF
180.54 MHz
Tx IF
181.80 MHz
Rx IF
0 MHz
RX IQ
TX IQ
VCTCXO
19.44 MHz
BaseBand
Rx IF
135.54 MHz
Rx VHF
271.08 MHz