To display peak, average, and peak/average statistics
This procedure shows you how to use features under [Marker Function]to
display peak, average, and peak-to-average statistical power measurements.
You can use these features to obtain the same results you get with CCDF
measurements. Unlike CCDF measurements, you can display these
statistical power measurements in any instrument mode as long as the
active trace contains time-domain data. This is useful because these
statistical power measurements give you a way to view power statistics
using the analog, digital, video, and wideband CDMA instrument modes.
Use CCDF measurements for the power distribution of main time results.
Use these statistical power measurements for demodulation results or
results from math functions.
1. Perform the previous task.
The previous task generates the random noise signal used by this task. It
also sets the input range and enables time-domain corrections.
2. Display time-domain data.
Press [
Measurement Data], [main time ch1].
3. Set the statistical percentage to 99.8%.
Press [
Marker Function], [peak/average statistics], [peak percent], 99.8%.
4. Select a statistical power measurement.
Press [
peak power].
5. Turn on the statistical power measurement.
Press [
statistics on],.
In many applications, the instantaneous power of a signal can be treated as
a random variable. Depending on the associated statistics, it may or may
not make sense to define power in terms of an absolute value. Instead,
power is defined in probablistic terms.
For example, you may determine that the instantaneous power of a given
signal is less-than-or-equal to 3.5 dBm 99.8% of the time. In this case, you
would say that the peak power is 3.5 dBm at a peak percent of 99.8%, or
the peak power will be below 3.5 dBm 99.8% of the time. Alternatively,
you could say that the instantaneous power will exceed 3.5 dBm 0.2% of
the time (100% – 99.8% = 0.2%). You can represent this probability
mathematically as:
Probability (P
inst
≤ 3.5 dBm)=99.8% or, more generically:
Probability (P
inst
≤ P
peak
)=Peak percent
where:
P
inst
= Instantaneous power
P
peak
= Peak power
Peak percent = probability associated with P
peak
Making Statistical Power Measurements
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