| abstract |
A circuit for use in an implantable cardiac pacemaker for use in processing intracardiac signals and methods of processing such signals. The circuit includes a passive filter 1 has a bandwidth of 0.1 to 80 Hz approximately. An amplifier 2 with switched capacitors presents at the output a dynamics of 0.8V approximately and a gain lower than 50. An analog-to-digital converter 3 with delta modulation, which is controllably variable in step and functions at two frequencies, one of 1 kHz approximately, the other of 4 kHz approximately. The circuit may be used for both processing said signals to identify spontaneous cardiac events and to telemeter an intracardiac ECG. |