Technical data

142 Chapter 5
Adjacent Channel Power
Using the Adjacent Channel Power Measurement
Adjacent Channel Power
Using the Adjacent Channel Power Measurement
Adjacent Channel Power measures the power of the carrier and the power of the
noise in its adjacent channels. The measurement results can help you determine
whether the power is set correctly and whether the transmitter filter is working
properly. Once you have set the limits, you can easily see whether a test falls within
those limits using the mask feature and the color-coded metrics. You can measure
the adjacent channel power on one to three adjacent channels on each side of your
center channel in the CDMA, W-CDMA, TDMA, GSM Edge and GPRS, AMPS,
NMT-450, Tetra, iDEN and Korean PCS channel bands.
CAUTION When measuring multiple adjacent channels, the combined channel power must not
exceed +20 dBm at the RF In port.
CAUTION The maximum power for the RF In (Port 1) and RF Out/SWR (Port 2) ports is
+20 dBm (100 mW). When using the 8481A/8482A or N8481A/N8482A with
Option CFT Power Sensors, the maximum input power applied to the Power Sensor
is +24 dBm (300 mW). When using the 8481D Power Sensor, the maximum input
power is +20 dBm (100 mW). When directly coupled to a base station (BTS) or
Access Network (AN), the test set can be damaged by excessive power applied to
any of these three ports.
To prevent damage in most situations when you directly couple the test set to a base
station, use the high power attenuator between the test set and the BTS.
NOTE For complex modulation such as CDMA, W-CDMA, 1xEV-DO and GSM, the
frequency error measurement is not accurate (see respective analyzers for detailed
frequency error results).
NOTE The RF in loss can be added manually or automatically by performing an insertion
loss measurement. For measurement instructions refer to “Performing (and
Calibrating) a Basic One Port Insertion Loss measurement” on page 47 or
“Normalizing and Performing a Basic Two Port Insertion Loss Measurement” on
page 125.