Cirrus Logic CRD5378, Manual

Page: 38 / 64

CRD5378
38 DS639RD2
3.3.6 Data Capture
The Data Capture sub-panel collects samples from the target board and sets analysis parameters.
When the Capture button is pressed, the requested number of samples are collected from the target board
through the USB port. The maximum number of samples that can be collected is 1,048,576 (1M). The
number of samples per channel should be a power of two for the analysis FFT routines to work properly.
After data is collected, analysis is performed using the selected parameters and the results are displayed
on the
Analysis panel. The selected analysis window , bandwidth limit , full scale code , and full scale volt-
age parameters can be modified for the data set currently in memory and the analysis re-run by pressing
the REFRESH button on the Analysis Panel.
Control Description
Total Samples Sets the total number of samples to be collected. Multichannel acquisitions split the
requested number of samples among the channels. A maximum of 1,048,576 (1M)
samples can be collected.
Window Selects the type of analysis windowing function to be applied to the collected data
set. Used to ensure proper analysis of discontinuous data sets.
Bandwidth Limit (Hz) Sets the frequency range over which to perform analysis, used to exclude higher-fre-
quency components. Default value of zero performs analysis for the full Nyquist fre-
quency range.
Full Scale Code Defines the maximum positive full-scale 24-bit code from the digital filter. Used during
FFT noise analysis to set the 0 dB reference level.
Full Scale Voltage Defines the maximum peak-to-peak input voltage for the nV/
√
Hz Spot Noise analy-
sis.
Total Captures Sets the number of data sets to be collected and averaged together in the FFT mag-
nitude domain. The maximum number of data sets that can be averaged is 100.
Capture Starts data collection from the target board through the USB port. After data collec-
tion, analysis is run using parameters from this sub-panel.
Remaining Captures Indicates how many more data captures are remaining to complete the requested
number of
Total Captures . A zero value means that the current data capture is the
last one.
Skip Samples Sets the total number of samples to be skipped prior to data collection. A maximum
of 64K samples can be skipped