Nokia 3105 Servicehandbuch
RH-48
System Module
CCS Technical Documentation
Page 20
©
2003 Nokia Corporation Confidential
Issue 1 11/2003
gain RF amplifier. The IF signal is converted up to RF with a differential output upcon-
verter and then fed to the RF amplifier. The RF amplifier has variable gain capability (RF
AGC) with up to 40 dB of dynamic gain control.
verter and then fed to the RF amplifier. The RF amplifier has variable gain capability (RF
AGC) with up to 40 dB of dynamic gain control.
The output of the Cell RF amplifier of Jedi is connected to an RF filter to reject TX noise
in the RX band.
in the RX band.
The output of the RF filter is connected to the PA. Out of the PA is an isolator, then
antenna.
antenna.
Synthesizer
Refer to the following figure for a block diagram that illustrates all three synthesizers
and how they interconnect in the system.
and how they interconnect in the system.
Figure 9: Synthesizer system block diagram
1st TX VHF LO Synthesizer (Jedi)
The TX VHF Synthesizer is integrated within the Jedi RFIC and generates the LO signals
for the IQ-modulator in Jedi. The synthesizer has an internal VCO with an external reso-
nator. The VCO operates at two times the CELL IF frequencies. A band-switch signal,
VCO_Band, is used to shift the center frequency of the external resonator.
for the IQ-modulator in Jedi. The synthesizer has an internal VCO with an external reso-
nator. The VCO operates at two times the CELL IF frequencies. A band-switch signal,
VCO_Band, is used to shift the center frequency of the external resonator.
The synthesizer is a dual-modulus prescaler type, and utilizes a phase detector with a
charge pump that sinks or sources currents, depending on the phase difference between
the detector input signals. The width of the pulses depends on the phase difference
between the signals at input of the phase detector. The main divider, auxiliary divider,
and reference divider are programmable through the serial interface to Jedi.
charge pump that sinks or sources currents, depending on the phase difference between
the detector input signals. The width of the pulses depends on the phase difference
between the signals at input of the phase detector. The main divider, auxiliary divider,
and reference divider are programmable through the serial interface to Jedi.
2nd RX VHF LO Synthesizer (Yoda)
The RX VHF Synthesizer is integrated within the Yoda RFIC and generates the LO signals
for the IQ demodulator in Yoda. The synthesizer has an internal VCO with an external
for the IQ demodulator in Yoda. The synthesizer has an internal VCO with an external
JEDI
VHF
counter
UHF
counter
Yoda
VHF
counter
367.2MHz
CELL:457.2MHz
CELLl Band UHF VCO
19.2MHz to
UPP
19.2MHz
VCTCXO
JEDI
VHF
counter
UHF
counter
Yoda
VHF
counter
367.2MHz
CELL:457.2MHz
CELLl Band UHF VCO
19.2MHz to
UPP
19.2MHz
VCTCXO