Frequency Hopping and Sweeping

You can define a staging list for performing frequency hops and sweeps. The entire staging list uses the same waveform loaded into the lookup memory. All stages are phase-continuous and differ only with the frequency generated.

Frequency Sweeping

A frequency sweep is the continuous generation of a single waveform with a linearly-changing frequency.

The following are the basic elements used to control the generation of a frequency sweep:

  • Start frequency—the first frequency generated in the frequency sweep.
  • End frequency—the last frequency generated in the frequency sweep.
  • Number of frequency steps—the number of segments into which a waveform is divided. Each frequency step corresponds to a particular frequency.
  • Frequency step duration—the amount of time the waveform is generated at a particular frequency.

These elements can be used to programmatically create a frequency sweep. For an example of a frequency sweep in Frequency List output mode, refer to the Fgen Sweep Generator example for LabVIEW or Sweep Generator example for LabWindows/CVI. For an example of a frequency sweep in Standard Function output mode, refer to Fgen 5404 Frequency Sweep example for LabVIEW or 5404 Frequency Sweep example for LabWindows/CVI.

A simple example of a frequency sweep is a chirp waveform—a sine wave produced with a linear sweep of frequency. Refer to the NI Analog Waveform Editor Help at ni.com/manuals for information about creating and configuring a chirp waveform using the AWE.

Frequency Hopping

Frequency hopping is similar to frequency sweeping, with the difference that the frequencies used in a frequency hop are not applied in a linear succession, but rather in an order defined by the user. You can use Frequency List, Arbitrary Sequence, or Script output mode to implement frequency hopping.