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. Refer to niFgen_Sweep_Generator_Example or niFgen_5404_Frequency_Sweep_Example for LabVIEW, or Sweep Generator or 5404 Frequency Sweep for LabWindows/CVI for an example of how this is accomplished.

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 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 mode, Sequence mode, or Script mode to implement frequency hopping.