Product Description

General function, construction and units
DN991444 © Nokia Corporation Draft 57 (98)
Issue 3-0 en Draft Nokia Proprietary and Confidential
Figure 20. Block diagram of the RF module
Transmitter (TX) part
The transmitter (TX) part includes a Frequency Hopping System (FHS) of its
own, two intermediate frequency blocks, an RF block, and a power control block.
In the TX part the modulation source, Gaussian Minimum Shift Keying (GMSK)
or 8 Phase Shift Keying (8-PSK), is generated in the Direct Digital Synthesis
(DDS) part of the Enhanced Up-converter ASIC (ETXA).
Two stages of up-conversion are used to achieve the carrier frequency. Filters are
used within the chain to achieve spectral purity.
The RF module includes a TX FHS phase-locked synthesizer, for either
frequency hopping between adjacent time slots or providing a fixed frequency
signal in non-hopping mode. The FHS part consists of separate VCO module and
PLL circuits. The TX FHS provides the local oscillator signal in the final up-
conversion stage of the TX chain.
RF module
RF
Duplex
filter
RF
section
IF sections
LNA
TRX
loop part
IF sections
Downlink
RF control
REF clocks
RF alarms
DIV IN
DIV OUT
Interface
to
baseband
module
ANT
RX synthesisers
TX synthesisers
TX part
RX part
Uplink