Filter
Top Products
Fast Fourier Transforms
TDS 620A, 640A, & 644A User Manual
Figure 3-23: Cursor Measurement of an FFT Waveform
10. Press Function (main) ➞ Paired (side).
11. Use the technique just outlined to place the vertical bar of each paired
cursor to the points along the horizontal axis you are interested in.
12. Read the amplitude between the X of the two paired cursors from the
top-most : readout. Read the amplitude of the short horizontal bar of the
selected (solid) cursor relative to either 1 V
RMS
(0 dB), ground (0 volts), or
zero phase level
(0 degrees or 0 radians) from the @: readout. Read the
frequency between the long horizontal bars of both paired cursors from
the bottom : readout.
Automated Measurements of an FFT
You can also use automated measurements to measure FFT math wave-
forms. Use the same procedure as is found under
Waveform Differentiation
on page 3-151.
There are several characteristics of FFTs that affect how they are displayed
and should be interpreted. Read the following topics to learn how to optimize
the oscilloscope setup for good display of your FFT waveforms.
Considerations for
Using FFTs