GW Instek GDS-1000A Series User Manual - Manual (Page 59)

MEASUREMENT
59
Math Operations
The Math operations can add, subtract, multiply or perform
FFT/FFT RMS on the input waveforms. The resulted waveform can
be measured using the cursors, and saved or recalled just like
normal input signals.
Overview
Addition (+) Adds the amplitude of CH1 & CH2 signals.
Subtraction (–) Extracts the amplitude difference between CH1 &
CH2.
Multiplication (×) Multiplies CH1 and CH2.
FFT Performs a FFT calculation on a signal. Four types
of FFT windows are available: Hanning, Flattop,
Rectangular, and Blackman.
FFT RMS Performs a FFT RMS calculation on a signal. RMS
is similar to FFT, however the amplitude is
calculated as RMS and not dB. Four types of FFT
windows are available: Hanning, Flattop,
Rectangular, and Blackman.
Hanning FFT
window Frequency resolution Good
Amplitude resolution Not good
Suitable for.... Frequency measurement on
periodic waveforms
Flattop FFT
window Frequency resolution Not good
Amplitude resolution Good
Suitable for.... Amplitude measurement on
periodic waveforms
Rectangular FFT
window Frequency resolution Very good
Amplitude resolution Bad