Tektronix SPECMON3 Manual page 164

RF Measurements
Results display for Adjacent Channel Power
Heading
Channel
Lower
Upper
Channel Power (Main)
xxx
Setting Channel Power and ACPR Settings Parameters (see page 153)
RF Channel Power Measurement
The RF channel power gives an indication of the total average (and other measures ) RF power in
a given channel.
For some communications systems, there is an "out-of-service" total power measurement defined in the
specifications that calls for a specified constant modulation. In this case, the output power should be
relatively constant. For many measurements, this may not be the case, and the Power Measurement
results will vary as the signal varies.
Average power is the square root of the sum of the squares of the voltage samples over the measurement
time.
The defined "channel" width for the Power Measurement defines the bandwidth and shape of the filter
used to remove any RF power on frequencies outside of the channel bandwidth.
Channel Power
The total RF power in the selected frequency band. The detection type used for measuring channel power
is Average. This means that the average of the linear (pre-log) samples is used to determine the channel
power. To measure channel power, use the ACLR measurement, and set the number of adjacent channels
to zero. This results in only the channel power being measured.
152
Description
Identifies the displayed channels. A1 means the first adjacent channel. A2 means
second adjacent channel. Adjacent channels are numbered according to their offset from
the Main channel. The closest channel is numbered 1. The next closest channel is
numbered 2; and so forth.
The power measured for the lower adjacent channel. Adjacent channel power
measurements are displayed in dB relative to the Main channel.
The power measured for the upper adjacent channel. Adjacent channels power
measurements are displayed in dB relative to the Main channel.
The power measured for the Main channel. The detection type used for measuring
channel power and adjacent channel powers is Average. This means that the average of
the linear (pre-log) samples is used to determine the power. The Main channel power is
displayed in dBm.
RF Channel Power Measurement
SPECMON3 & SPECMON6 Printable Help