A resonant shaker includes a support tray for supporting a target carrier.
A sensor generates an electrical signal that is related to an
acceleration of the support tray. A linear drive motor includes an
armature that is coupled to the support tray. The linear drive motor
provides an oscillating drive force to the support tray in response to a
drive current applied to the linear drive motor. The resonant shaker also
includes a controller. The controller receives the electrical signal from
the sensor and a drive signal that is related to the drive current. The
controller transmits a modified drive current to the linear drive motor
in response to a predetermined phase relationship between the electrical
signal and the drive signal.