Uhf Vco - Nokia Mobile Phones NSE-5 Series Service Manual

PAMS
Technical Documentation
VHF VCO
The 464 MHz VHF VCO (G702) signal is used to generate the 116 MHz–
and 232 MHz signals inside SUMMA. The 116 MHz signal is used in GSM
transmitter and in PCN receiver. The 232 MHz signal is used in PCN
transmitter.
Fault finding chart for VHF VCO
The fault finding is as described for UHF VCO with following exceptions:

UHF VCO

1 SUMMA N700 pin 21
2 UHF VCO G700
3 SUMMA UHF PLL
4 UHF VCO G700 OUT–pin
The exceptions will be inside (.) in the fault finding chart for the UHF VCO.
UHF VCO
UHF VCO (G700) is used to generate the first injection for RX (GSM
2012.4 ... 2061.6 MHz, PCN 1992.2 ... 2066.8 MHz) and the final injection
for TX (GSM 2012.4 ... 2061.6 MHz, PCN 1942.2 ... 2016.8 MHz). The
output frequency of the module depends on the DC–control voltage
coming from SUMMA.
Fault finding chart for UHF VCO and 13 MHz reference oscillator
Oscilloscope
SUMMA N700 pin 21
(12)
Vdc = 1.8 ... 3.0 Volt
Oscilloscope
SUMMA N700 pin 15
Vac = > 2 Vpp, 13
MHz
Oscilloscope
VCTCXO G701 OUT–
pin
Issue 1 07/99
VHF VCO
changed to SUMMA N700 pin 12
changed to VHF VCO G702
changed to SUMMA VHF PLL
changed to VHF VCO G702 OUT–pin
No
No
Troubleshooting
Vdc = 1.8 ... 3.0 Volt
Pout > –3 dBm
UHF VCO G700 is
OK
(VHF VCO G702)
Yes VCTCXO G701 is
OK
SUMMA UHF PLL
is OK
(SUMMA VHF
PLL) Supply's are
OK
VCTCXO
G701 is OK
Check
NSE–5
Page 37