Agilent Technologies PSA Series Manual page 301

Modulation SINAD Measurement Concepts
Purpose
Modulation SINAD (SIgnal to Noise And Distortion) measures the amount of
Modulation SINAD contained in the modulated signal by determining the ratio of
fundamental power to harmonic and noise power. Modulation SINAD is reciprocal
of modulation distortion provided by Modulation Distortion measurement. This is
another way to quantify the quality of the modulation process
Measurement Technique
Modulation SINAD is defined as:
Equation 5-4
dB
where: P
P
P
and noise.
See Figure 5-11 on page
to remove DC, then the filtered signal is transformed by an FFT into frequency
domain. Next, total power in the total filter band is measured as P
power of the modulated signal is computed as P
P
total
can be expressed as dB or %.
Chapter 5
= 20
ModulationSINAD
= the power of the total signal,
total
= the power of the wanted modulating signal, and
signal
− P
= the total unwanted signals which include harmonic distortion
total signal
299. First, the received signal is demodulated and filtered
− P
to P is calculated. The result is signal's Modulation SINAD. It
total signal
Analog Modulation Concepts
P
× total
log ---------------------------------- -
P – P
total signal
, the square root of the ratio of
signal
Concepts
, the peak
total
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