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Frequency Sweep (Swept Sine)
The swept sine waveform produces a sine wave which changes frequency over time. The start and stop frequencies determine the limits of the sweep signal. The start frequency can be less than the stop frequency in which case the sweep frequency will decrease over time.
The sweep type can be either Linear or Logarithmic. This determines the rate of change of the sweep frequency.
Jump Back to Start Frequency - when the stop frequency is reached the signal will immediately start again at the start frequency
Sweep Back to Start Frequency - when the stop frequency is reached the signal will sweep back to the start frequency.
Stop After a Single Sweep - the signal generator will stop after the sweep completes; otherwise it will repeat continuously until the generator is stopped.
Sweep Time - specifies how long the frequency takes to change from the start to the stop limits. This value is specified in milliseconds.
Swept sine waveforms are useful for frequency response testing. Set the averaging block size to 1 and use the Peak Hold option to capture the peak amplitude as the signal is swept across the frequency span. The larger the FFT size used, the longer the required sweep time.
Sweeping too fast with large FFT sizes will "smear" the amplitude as the signal is changing frequency withing the underlying time series segment.
See Also: Level Step, Signal Generator