A telemetry system for transmitting digital data from an implanted pacer to an external programming/receiver unit includes a voltage-controlled pulse generator having an output period proportional to its input voltage magnitude. The external receiver unit includes a pulse period detector to generate...http://www.google.com.au/patents/US4757816?utm_source=gb-gplus-sharePatent US4757816 - Telemetry system for implantable pacer
