User's Manual

F32700N25.doc Page 24
The plot in Figure 2-4 is the same as before but now the scope is in the peak detect
acquisition mode. After the Fixed Radio detects a step response in the RSSI (caused
by a down-link transmission), the radio's microcontroller waits an amount of time equal
to the programmed value of the "carrier detect delay time" then instructs the modem to
look for frame sync. When the microcontroller instructs the modem to look for frame
sync, it asserts the modem's CS line (active low). In this plot, the modem's CS line can
be seen to transition low approximately 3 milliseconds after the base station's
transmitter has come up to full power.
The recovered modulation should be centered at approximately 2.5 VDC and should
have an amplitude of approximately 800 mV peal-to-peak as indicated in the plot above.
Message success Rate
Perform the following steps to verify transmit and receive data performances:
Step 1 With the same base station at the same setting, using IPlink to measure the
data quality and Message success rate (MSR). IN IPlink open PLOT menu,
then select new. New plot table appears, select the following parameters; IP
address=172.16.23.xxx, wherte (xxx) is the address of the base station, delay
Figure 2-4: Downlink Timing Characteristics Plot in Peak Detect Acquisition Mode