Table of Contents
Advertisement
The Display
Control knobs provide
vertical expansion (up
to 10 times)
and vertical
position
control.
To read the amplitude and frequency of the data point, the Marker can
be moved over into the frequency domain by going beyond the right hand
edge of the time domain waveform.
The Time Cursors can be moved beyond the right hand edge of the time
domain
waveform
and
thus
become
Frequency
Cursors,
providing
simultaneous
readout
of frequency
difference
and of amplitude
difference between two points on each frequency domain trace.
Table
11.1
Display
Types
Display
type
Unit
Vertical
position
of zero
Power Spectrum
dBm
(mark)
Power Density
spectrum
dBm
(mark)
Magnitude
V
-3 div
Phase
degree
0 div
Real
Part
V
0 div
Imaginary Part
V
0 div
Note:
Vertical position of 0 dBm varies with the source waveform's
gain.
A mark at the left hand edge of the screen indicates
the dBm
level
of a trace. Generally,
a sinusoidal
source waveform of 8 div
peak-peak will give a spectrum point of about +3 div at any gain.
Since the computation of FFT may take up to 1 minute (for a Transform
Size of 25000 points), it is possible to interrupt an undesired FFT
either by turning off the corresponding
trace(s)
or by pushing the
Redefine button, if the FFT trace is the selected trace.
11.2
Modification
to WPO1 Functions
With
the
option
WP02 (FFT)
installed,
the
WP01 functions
are
modified
as follows:
When any WP01 function
operates
on a frequency
domain waveform
(a
result of FFT processing), the Max # of Points value selected in the
menu of the function is ignored. Instead, the number of points of the
frequency domain waveform is used for further processing.
11-3
Fast Fourier Waveform Processing
Option (WP02, V 2.06FT)
Advertisement
Table of Contents
