CDB5378 datasheet(43/72 Pages) CIRRUS

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CDB5378

DS639DB3

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 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. 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/rtHz 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

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