Tektronix RSA6100A Series, Help Manual

Page: 123 / 415

Analog Modulation > AM Parameters Tab
Parameters Tab
The Parameters tab enables you to specify two parameters that control the carrier amplitude detection.
Setting Description
Average Selects the Average method for computing the average baseline for measurements.
Median Selects the Median method for computing the average baseline for measurements.
Measurement BW Speci fi es the bandwidth about the center frequency at which measurements are made.
xxx
AM Modulation
An amplitude modulated carrier can be described mathematically by:
A, in the above equation, represents the carrier amplitude, a(t) represents the time-varying modulation
and
ω
0
represents the carrier frequency.
The signal modulation envelope is given by:
There are several ways to express the AM modulation depth, expressed as a percentage.
Peak method
Trough Method
Max-Min Method
In each case, the value of the carrier amplitude, A , needs to be estimated from the input signal.
The instrument represents signals in a sampled form. The sampled envelope can be expressed as a function
of sample index K and sampling period T as:
The instrument allows the choice of two methods for estimating the carrier amplitude:
RSA6100A Series Real-Time Spectrum Analyzers Help
111