User's Manual

F32700N25.doc Page 22
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As seen in the above plot, the fixed radio'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 Fixed Radio should look identical 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.
Figure 2-2 displays another oscilloscope plot of an up-link data message from the Fixed
Radio to the base station. As in the last plot, channel 1 is connected to the base
station's RSSI (J5-12), channel 2 is connected to the base station's recovered
modulation test point, and channel 3 is connected to the base station's modem chip
select line (U16-13). The scope's acquisition mode is now in the peak detect mode.
This enables the base station's modem CS (Chip Select) line to be viewed.
Figure 2-2: Another Oscilloscope Plot of an Uplink Data Message