Abstract: A filter is disclosed that actively controls one or more filter characteristics, such as the cut-off frequency of a selected filter pole, while minimizing the value of selected filter components such as the capacitor components. This helps improve the performance, reliability and yield of the filter. The filter rejects a selected frequency component or frequency band by actively providing an offset signal that effectively cancels the rejected frequency component or frequency band, while allowing the remaining frequency components or frequency bands to pass relatively freely to the output of the filter. The offset signal may also be used to actively reject a DC offset voltage or current from the input signal.

Abstract: A switched capacitor ventricular sense amplifier for an implantable pulse generator having unique control of the switching clock for minimization of transients during the period just preceding, during and following an atrial paced event. The timing is modified to discontinue switching during this period. This ensures that transients occurring as a result of functionally disconnecting and subsequently reconnecting the sensing lead with the sense amplifier are not propagated within the switched capacitor bandpass filter. An alternative approach is to increase the clocking rate during the blanked period to ensure that the transients created by the atrial pace or by disconnecting and reconnecting the sensing lead are rapidly processed by the switched capacitor bandpass filter and that processing is completed shortly following the atrial paced event. This alternative approach requires a gate at the sense amplifier output to disable propagation of any transients processed.