Rf In General - Nokia 616 Service Manual

TFE-4/RV-1
TF4 Technical Information
TXC
Figure 30: TX measurements points for TXC, TXP signals

RF in general

The RF part is a dual-band direct conversion transceiver. Using direct conversion no
intermediate frequencies are used for up- or down- conversion.
The VCO is set to either twice or four times (depending on the band used) the wanted RX
or TX frequency. The VCO frequency is divided by either 2 or 4 and fed to the mixers
(down-conversion) or modulators (up-conversion). Up- or down- conversion is done in
one step, directly between RF frequency and DC. All up and down-conversion takes place
in the RF ASIC named Mjoelner (N601).
The Mjoelner RF ASIC also contains the PLL and LNAs for all used bands. A DC control
section is responsible to power and/or control EGSM TX buffer, detector and antenna
switch. The Mjoelner RF ASIC is controlled via a serial bus.
It contains an integrated VCXO which uses an external 26 MHz Xtal. No analogue AFC
signal is needed. AFC is done via the serial interface of Mjoelner.
For the interface between Mjoelner RF ASIC and UPP and Bluetooth an 26 MHz reference
clock is used. An external 26 MHz reference clock buffer is used to drive Bluetooth mod-
ule.
The RF supports HSCSD (High Speed Circuit Switched Data) and GPRS (General Packed
Radio Service), meaning multi-slot operation. This will not require special equipment or
procedures in repair situations.
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Issue 2.0 Mar/2005