Techniques to acquire and track a received signal instance based on one or more transmitted pilots. The device simultaneously disables the microphone; and turns off the visual indication when the device is in secure state. The fish are movable transversely to their longitudinal axis on an essentially vertical circular path. The driver circuit further includes a duty cycle monitor configured to monitor an output of the at least one output driver leg when the at least one output driver leg is isolated from the remaining output driver legs, and to provide the monitored output to the duty cycle adjuster.