Abstract: A method of and apparatus for telemetering analog and digital data transcutaneously between an implantable medical device and an external receiver, such as between an external programmer and an implantable cardiac pacer. A damped carrier at 175 kilohertz is pulse position modulated by digital data. The data, along with synchronization and identification codes, are positioned into predefined ranges within predefined frames as measured by individual time periods. The data is uniquely identified by the position of one or more bursts of the carrier within the predefined range. An automatically initiated hand shake protocol maintains the link over slight variations in programmer head position with an indicator notifying the operator when repositioning is required. Analog data may be transferred in digital form or alternatively transferred using phase modulation of the carrier bursts. A cyclic redundancy code is used for link error detection.

Abstract: A method and apparatus for determination of battery end-of-service in a medical device in which the medical device comprises a cathode limited electrochemical cell having an active metal anode and a manganese dioxide cathode and means for digital telemetry of cell voltage. The sloped, well defined voltage curve of such a cell during cell discharge combined with precise information available through digital telemetry allows for improved determination of battery end-of-service for the medical device.

Abstract: A method of and apparatus for telemetering both analog and digital data transcutaneously between an implantable medical device and an external receiver, such as between an external programmer and an implantable cardiac pacer. A damped carrier at 175 kilohertz is pulse position modulated by digital data. The data, along with synchronization and identification codes, are positioned into predefined ranges within predefined frames as measured by individual time periods. The data is uniquely identified by the position of a burst of the carrier within the predefined range. An automatically initiated hand shake protocol maintains the link over slight variations in programmer head position with an indicator notifying the operator when repositioning is required. Analog data may be transferred in digital form or alternatively transferred using phase modulation of the carrier bursts. A cyclic redundancy code is used for link error detection.

Abstract: A method and apparatus are disclosed for telemetering both analog and digital data from an implantable medical device to an external receiver, such as between an implanted cardiac pacer and its external programming equipment. Analog data is first converted to digital format by an analog-to-digital converter, such that the transmission is digital data. A damped carrier at 175 kilohertz is pulse position modulated by the data. The modulation scheme defines a frame of slightly less than 2 milliseconds. The frame is divided into 64 individual time periods using a crystal clock. The data, along with synchronization and identification codes, are positioned into predefined ranges within each frame as measured by the individual time periods. The data is uniquely identified by the position of a burst of the carrier within the predetermined range.