RH-13
Troubleshooting
CCS Technical Documentation
Page 34
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Nokia Corporation
Issue 1 11/02
Step 2. Local oscillator checking
Carrying out this step VCO signal of 1st and 2nd mixers can be checked. 2nd mixer RX
VHF VCO frequency is constant 268.08 MHz but for the 1st mixer UHF VCO frequency
depends on the channel. The UHF VCO frequencies for the 1st mixer are:
Channel 991:
2006.16 MHz
Channel 380:
2030.88 MHz
Channel 799:
2056.02 MHz
1 Set signal generator frequency to 881.4091125 and level to -80 dBm.
2 Set phone to TDMA mode and select RF Test UI in Phoenix (Maintenance => Test-
ing => RF Test).
Figure 17: RF Test.
3 Make sure that signal generator allows phone TX power going to its output. Use
low power level, for example 10. Set channel to 380 and select "Write Init".
4 Set spectrum analyzer settings as following:
• Center frequency: 268.08 MHz, Span: 200 kHz
• RBW: 3 kHz, reference level: 0 dBm
5 Connect spectrum analyzer probe on the inductor L818 and record RX VHF VCO
signal level and frequency. Signal level should be around -25 dBm and frequency
268.08 MHz.
6 Set spectrum analyzer settings as following:
• Center frequency: 2030.88 MHz, Span: 200 kHz
