Fft Capture - Analog Devices EVAL-ADAQ4003FMCZ User Manual

UG-1533

FFT CAPTURE

The traditional ac characteristics of the converter can be
displayed in the FFT tab. The FFT tab displays signal-to-noise
ratio (SNR), signal-to-noise-and-distortion ratio (SINAD),
THD, and spurious-free dynamic range (SFDR) data. The data
can also be displayed in the time domain. To perform an ac test,
apply a sinusoidal signal to the EV-ADAQ4003PMDZ at
the SMB inputs, J1 and J2. Low distortion, better than 100 dB,
is required for true evaluation of the device. To achieve low
distortion, the input signal can be filtered from the ac source.
A band-pass filter can be used, but the center frequency must
match the test frequency of interest. Furthermore, if using a low
frequency band-pass filter when the full-scale input range is
EVAL-ADAQ4003FMCZ
more than a few volts peak-to-peak, use the on-board amplifiers to
amplify the signal, thus preventing the filter from distorting the
input signal.
Figure 30 displays the histogram of the captured data that includes
the following:
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•
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Figure 30. FFT Tab
(ADAQ4003 Running in Turbo Mode)
Rev. 0 | Page 16 of 31
Evaluation Board User Guide
Spectrum information
Fundamental frequency and amplitude in addition to the
second to fifth harmonics
Performance data (SNR, Dynamic Range, THD, SINAD,
and noise performance)