US Patent 7089823 Vibratory mechanism controller

A controller for use in a vibratory mechanism includes an amplitude control circuit that generates an amplitude control signal that varies from a minimum value to a maximum value. The vibratory mechanism is adapted to vibrate at an amplitude based on an amplitude control signal characteristic. Additionally, the controller includes a frequency control circuit that is operatively coupled to the amplitude control-circuit to produce a frequency control signal that varies based on the amplitude control signal characteristic.