Sweep Rate: Sets the sweep rate to a specific value.
Sweep Run: Starts a frequency sweep.
Sweep Hold: Stops a frequency sweep.
Sweep Restart: Stops a currently running frequency sweep and starts it again with the
start conditions of the previous sweep.
The following picture shows a frequency sweep (sweep rate: 500 kHz/us). After a few
clock cycles, the sweep is stopped again, the frequency is not increasing anymore.