Synthesizers; 19.2 Mhz Reference Oscillator - Nokia RH-13 Series Troubleshooting Manual

CCS Technical Documentation

Synthesizers

There are five oscillators generating the needed frequencies for RF section. 19.2 MHz ref-
erence oscillator, 2GHz UHF VCO, TX VHF cascade amplifier VCO both RX VHF VCO and
BB VHF integrated in Safari. RX VHF frequency is 268.08 MHz in TDMA and 266.4 MHz in
GSM and TX VHF has four fixed frequencies, 358.08 MHz TDMA and 356.4 MHz GSM for
lowband and 426.4 MHz in GSM and 428.16 MHz in TDMA upper band. VCO's operating
frequencies are controlled by PLL-circuit of SAFARI. All locals are locked to a stable 19.2
MHz reference oscillator.
The frequency range for 2GHz UHF VCO is: 2004.8 ... 2124 MHz. The output frequency
range for the lower band is from 2006.16 to 2056.02 MHz in TDMA and from 2004.8MHz
to 2054 in GSM. In TDMA upper band the output frequency range is from 2064.12 MHz
to 2124 MHz and GSM 2063.40 to 2123 MHz.
BB-PLL frequencies are in TDMA 77.76 MHz and in GSM 78 MHz
It is a practical way to check out synthesizer status by measuring the control voltage of
the VCO from Integrator capacitor. If the voltage is stable and reasonable, local oscilla-
tors are running correctly.

19.2 MHz reference oscillator

The 19.2 MHz oscillator frequency (G801) is controlled by UEM. This 19.2 MHz signal is
connected thru SAFARI to PLL-circuits.
All synthesizers use divided VCTCXO signal as a reference signal for Phase locked loop to
provide correct LO-frequency.
BB-PLL provides to the BB needed clock signals.
Issue 1 11/02 ãNokia Corporation
RH-13
Troubleshooting
Page 63