Nortel DualMode 800, Maintenance Manual

Page: 163 / 216

DRU receive tests 11-25
Wireless Solutions DualMode 800 Enclosure Maintenance Manual MTX08
Receive sensitivity test
The usable sensitivity of a receiver is the minimum level of a standard RF
signal required to produce 12 dB SINAD, C-message weighted. This test
ensures that the DRU meets the minimum requirement of receive sensitivity.
Receive and transmit audio line sensitivity test
This test ensures that both the receive audio signal level and the transmit
audio signal level of the DRU meet the required specifications in the AMPS
mode.
Step Action Observation
1 Ensure that the DRU configurations are as
listed in Table 11-1 for the Receive Sensitivity
test.
Note: SAT TX must be set to off in this test.
Use the G command to set SAT TX to off, if
necessary.
2 Use the J command to turn RF loopback on.
Use the R command to unmute TX RX audio.
Use the C command to turn PA carrier on. Loopback field shows:
RF
Audio status field shows:
TX RX
PA status field shows:
ON
3 Select the SINAD meter on the
communications monitor.
4 Using the communications monitor, apply a
-50 dBm on-channel RF signal modulated
with a 1 kHz tone at
±
8 kHz deviation to the
DRU under test.
The SINAD reading should be much greater
than 12 dB.
5 Reduce the level of the RF signal until a 12
dB SINAD (C-message weighted) is
indicated on the SINAD meter. Check the RF
signal level on the communications monitor. The RF signal level must be:
less than -105 dBm
6 Record the RF signal level on the test forms.