NSW-6
System Module SE2
PAMS Technical Documentation
Page 39
Issue 1 12/99
Nokia Mobile Phones Ltd.
RF Module
Technical Summary
The RF module converts the signal received by the antenna to a
baseband signal and vice versa.
It consists of a conventional superheterodyne receiver and a transmitter
for each band and also two frequency synthesizers for the required
mixing.
The RF module includes one integrated circuit, the EROTUS a BiCMOS
ASIC.
The dual–band RF–module is capable for seamless operation between
800 MHz and 1900 MHz bands. In practise this means capability to
cross–band hand–offs and maho–measurements.
The EROTUS includes:
– Limiter amplifier for the analog receiver
– An AGC amplifier for the digital receiver
– A receiver mixer for the 450kHz down conversion
– PLLs for the 1GHz UHF and VHF synthesizers
– IQ–modulators for the transmitter
– A power control circuit for the transmitter and the AGC amplifier
The power amplifiers (PAs) are GaAs HBT MMICs. They comprise two
800 MHz and three 1900 MHz amplifier stages with input and interstage
matching.
The LNA MMICs include:
– A LNA for each band with a step AGC
– Down converters for the receiver
– A prescaler for the LO buffer
On the next page is a graphical presentation of the used Frequency Plan.
RF Frequency Plan
Intermediate frequencies of the RX are the same in all operation modes.
RX/TX LO and TX IF modulator frequencies are different in TDMA800
and TDMA1900 operation modes. See figure below for details.
