Modulation Sinad Measurement Concepts; Purpose; Measurement Technique - Keysight X-Series Measurement Manual

Concepts

Modulation SINAD Measurement Concepts

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 the
reciprocal of the modulation distortion provided by the Modulation Distortion
measurement. This is another way to quantify the quality of the modulation
process.

Measurement Technique

Modulation SINAD is defined as:
Equation 2-5
First, the received signal is demodulated and filtered to remove DC, then the
filtered signal is transformed by an FFT into the frequency domain. Next, total
power in the total filter band is measured as P
modulated signal is computed as P
P
total
be expressed as dB.
Keysight N9063C Analog Demod Measurement Guide
dB
=
ModulationSINAD
where: P = the power of the total signal,
total
P = the power of the wanted modulating signal, and
signal
P - P = the total unwanted signals which include harmonic
total signal
distortion and noise.
- P is calculated. The result is the signal's Modulation SINAD. It can
signal
P
total
- - - - - - - - - - - - - - - - - - - - - - - - - - - -
20 log
×
P P
–
total signal
total
, the square root of the ratio of P
signal
, the peak power of the
to
total
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