Using Features for Advanced Applications
TDS 684A, TDS 744A, & TDS 784A User Manual 3–161
Rectangular Window
0 dB
-20
-40
-50
Hanning Window
0 dB
-20
-40
-60
-80
Hamming Window
0 dB
-20
-40
-60
Blackman-Harris Window
0 dB
-20
-40
-60
-80
-100
-101
FFT Window Type Bandpass Filter
0.89
–3 dB Bandwidth Highest Side Lobe
1.28
1.28
1.28
–13 dB
–32 dB
–43 dB
–94 dB
Figure 3–94: FFT Windows and Bandpass Characteristics
Care should be taken when using bell shaped windows to be sure that the most
interesting parts of the signal in the time domain record are positioned in the
center region of the window so that the tapering does not cause severe errors.
Waveform Differentiation
The Advanced DSP Math capabilities of the TDS Oscilloscope include
waveform differentiation. This capability allows you to display a derivative math
waveform that indicates the instantaneous rate of change of the waveform
acquired. This section describes how to setup the oscilloscope to display and
measure derivative math waveforms.