Boonton 4540 Peak Power Meter Quick Start Manual de usuario descargar pdf (Pagina 32)

4540 Power Meter

Quick Start Guide

STATISTICAL MODE

Certain signals are completely random and

provide no event that can serve as a trigger

for measurements. CDMA or OFDM are

common examples. Such signal

“randomness” places a challenge to

measurements but the Statistical Mode of the

4540 offers an easy solution.

Statistical Mode is only available

when a peak power sensor is

connected to the 4540. It is the best

choice for analyzing “noise-like”

signals that are modulated in a

random, non periodic fashion.

Statistical mode yields information

about the probability of occurrence

of various power levels without

regard for when those power levels

occurred. Many digitally modulated

spread-spectrum formats use a

bandwidth coding techniques or

many individual modulated carriers

to distribute a source’s digital information over a wide bandwidth, and temporally

spread the data for improved robustness against interference. When these

techniques are used, it is difficult to predict when peak signal levels will occur.

Analysis of millions of data points gathered during a sustained measurement of

several seconds or more can yield the statistical probabilities of each signal level

with a high degree of confidence. Statistical Mode is best of the following types of

measurements:

• Moderate signal level (above about -40dBm except when modulation is

“off”).

• “Noise-like” digitally modulated signals such as CDMA (and all its

extensions) or OFDM when probability information is helpful in analyzing

the signal.

• Any signal with random, infrequent peaks, when you need to know just

how infrequent those peaks are.

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Boonton 4540 Peak Power Meter Quick Start Manual de usuario Pagina 32