User's Manual

SECTION 4: FACTORY TEST PROCEDURE
M64450G25-FCCRpt.doc Page 37
Step 11 After completion of Data Quality and MSR tuning, record Firmware Settings. File
the Tune and Align Data Sheet with the Firmware setting in the IPMN Network.
Hardware Timing Troubleshooting
For trouble shooting data quality and MSR failures hardware timing can be verified as follows. The figure
below is an oscilloscope plot of a down-link data message from the base station to the mobile. Channel 1
is connected to the mobile's RSSI test point, Channel 2 is connected to the mobile's recovered
modulation (TP1), and Channel 3 is connected to the mobile’s modem chip select line. The scope’s
acquisition mode is high-resolution.
As can be seen from this plot, the base station's transmit carrier has ramped up to full power (Channel 1)
in just a few milliseconds. The recovered modulation (Channel 2) is stable by this time. There follows a
few milliseconds of quiet time followed by 12 milliseconds of symbol sync time.
The recovered modulation from a base station should look similar to this plot. The recovered modulation
signal should be approximately 1.0 Volts peak-to-peak and should be centered at approximately 2.5 VDC
as is indicated in the figure above.
Below is another oscilloscope plot of an up-link data message from the mobile radio to the base station.
As in the last plot, Channel 1 is connected to the mobile's RSSI test point, Channel 2 is connected to the
mobile's recovered modulation test point (TP1), and Channel 3 is connected to the mobile's modem chip
select line. The scope's acquisition mode is now in the peak detect mode. This enables the mobile’s
modem CS (Chip Select) line to be viewed.