Nokia NHM-8NX Series Troubleshooting Instructions page 40

NHM-8NX
Troubleshooting Instructions
26MHz signal is divided by 2 to achieve 13MHz inside the UPP IC (D400). The 26 MHz
signal from the VCXO can be measured by probing R425 (must be measured on the UPP
side of R425 i.e. the end not connected to C425). The level at this point is approx.
700mVpp. Frequency of this oscillator is adjusted by changing the AFC-register inside the
Mjoelner IC. This is done via the Mjoelner serial interface.
Example Signal Measured at VCXO output (R425)
Page 40
Figure 20: VCXO 26 MHz waveform
ãNokia Corporation
PAMS Technical Documentation
Issue 1 05/02