CDB5521 Datasheet, PDF (17/28 Pages) Cirrus Logic – Evaluation Board and Software

CDB5521/22/23/24/28
- Window - Used in the Power Spectrum
Window to calculate the FFT. Windowing
algorithms include the Blackman, Black-
man-Harris, Hand, 5-term Hodie, and 7-
term Hodie. The 5-term Hodie and 7-term
Hodie are windowing algorithms developed
at Crystal Semiconductor. If information
concerning these algorithms is needed, call
technical support.
- Average - Sets the number of consecutive
FFT’s to perform and average.
- Limited Noise Bandwidth - Limits the
amount of noise in the converters band-
width. When set to zero, no limited noise
calculations are done.
- FFT Bandwidth - Used in the Power Spec-
trum Window to allow user-scalability of
the frequency axis. When set to zero, the
axis is auto-scaled to one-half the output
word rate.
- OK - Accept the changes
• MAGNITUDE
Displays the y-axis value of the cursor on the
Histogram.
• MAXIMUM
Indicator for the maximum value of the collect-
ed data set.
• MEAN
Indicator for the mean of the data sample set.
• MINIMUM
Indicator for the minimum value of the collect-
ed data set.
• Output
Control that calls a pop-up menu. This menu
controls three options:
1) save current data set to a file with the CDB-
CAPTURE format
2) print current screen, or
3) print current graph.
• RESTORE
Restores the display of the graph after zoom has
been entered.
• STD. DEV.
Indicator for the Standard Deviation of the col-
lected data set.
• VARIANCE
Indicates the Variance for the current data set.
• ZOOM
Control icon that allows the operator to zoom in
on a specific portion of the current graph. To
zoom, click on the ZOOM icon, then click on the
graph to select the first point (the 1st point is the
top left corner of the zoom box). Then click on
the graph again to select the second point (the
2nd point is the bottom right corner of the zoom
box). Once an area has been zoomed in to, the
OUTPUT functions can be used to print a hard
copy of that region. Click on RESTORE when
done with the zoom function.
2.7 Frequency Domain Window (i.e. FFT)
The following describe the controls and indicators
associated with the Frequency Domain Analysis
(Figure 8).
• CANCEL
See description in Section 2.6, Histogram
Window Overview.
• Channel
See description in Section 2.6, Histogram Win-
dow Overview.
• COLLECT
See description in Section 2.6, Histogram Win-
dow Overview.
DS317DB2
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