National Instruments NI Spectral Measurements Toolkit - Manual (Page 16)

NI Spectral Measurements Toolkit User Guide 16 ni.com
Figure 5. Spectrogram Process Example
The SMT Config Zoom STFT VI specifies the spectrogram in terms of
its center frequency, frequency span, and time span. The frequency span
controls the FFT zoom. If the center frequency is 10 MHz and the span is
2 MHz, the SMT Config Zoom STFT VI calculates the spectrogram from
9 MHz to 11 MHz. The time span specifies the time interval from the center
of the first window to the center of the last window. The VI also has
advanced parameters for specifying the spectrogram, including window,
resolution bandwidth, RBW definition, frequency points, time points, and
1.0
0.8
0.6
0.4
0.2
0.0
–0.2
–0.4
–0.6
10 30 40 50 60 70 75
T
F
Time Span
Window
Signal
Amplitude
FFT
FFT
Time (µs)
0 20