LeCroy 6000 SERIES, Operator'S Manual

Page: 214 / 409

Operator's Manual
212
ISSUED: October 2003 WR6K-OM-E Rev A
The table of Coefficients of Window Functions lists the coefficients a
m
. The window functions seen
in the time domain are symmetric around the point k = N/2.
Coefficients of Window Functions
Window Type a
0
a
1
a
2
Rectangular 1.0 0.0 0.0
Hanning (Von
Hann)
0.5 –0.5 0.0
Hamming 0.54 –0.46 0.0
Flattop
0.281 –0.521 0.198
Blackman–
Harris
0.423 –0.497 0.079
FFT SETUP
To Set Up an FFT
1.
In the menu bar touch Math , then Math Setup... in the drop-down menu.
2.
Touch a Math function trace button: F1 through Fx The number of math traces available
depends on the software options loaded on your scope. See Specifications.; a pop-up
menu appears. Select FFT from the menu.
3.
Touch the Single or Dual (function of a function) button if the FFT is to
be of the result of another math operation.
4.
Touch inside the Source1 field and select a channel, memory, or math trace on which to
perform the FFT.
5.
Touch inside the Operator1 field: Select FFT from the pop-up menu if you selected
Single function. Select another math function if you selected Dual function. Then touch
inside the Operator2 field and select FFT from the pop-up menu.
6.
In the right-hand dialog, touch the FFT tab.
7.
Choose whether to Truncate
1
or Zero-fill
2
the trace display.
1
When the FFT transform size does not match the record length, you can truncate the record and perform an FFT on the
shorter record. This will increase the resolution bandwidth.