Patent ID: 6201993
Filing Date: 2001-03-13
Classification: A61N,Y10S

Abstract:
An external programmer for receiving information-encoded, telemetry uplink signals transmitted from an implantable medical device (IMD) telemetry antenna and transmitter circuit in an IMD in a telemetry uplink transmission, said external programmer comprising:a programmer telemetry antenna tuned circuit comprising at least one antenna coil and at least one tuning capacitor, the programmer telemetry tuned circuit adapted to be driven into oscillation to generate tuned circuit output signals in response to telemetry uplink transmissions of telemetry uplink signals and in response to electrical noise, whereby the tuned circuit output signals can exhibit noise artifacts due to contamination by such electrical noise;a telemetry receiver section for detecting and demodulating the telemetry uplink signals from the tuned circuit output signals and providing a demodulated uplink signal having a demodulated uplink signal amplitude that varies with time as a function of telemetry uplink signal amplitudes and noise artifacts;an adaptive comparator circuit for comparing the demodulated uplink signal amplitude with an adaptive threshold signal and providing a receiver output signal when the demodulated uplink signal amplitude exceeds the adaptive threshold amplitude of the adaptive threshold signal, the comparator circuit further comprisingmeans for filtering and integrating the demodulated uplink signal to derive an adaptive threshold amplitude that is proportional to and adapts to the amplitude of noise artifacts in the demodulated uplink signal; andcomparison means having a first input terminal for receiving the demodulated uplink signal and a second input terminal for receiving the adaptive threshold signal and an output terminal for comparing the demodulated uplink signal amplitude with the adaptive threshold amplitude and providing the receiver output signal at the output terminal only when the telemetry signal amplitude in the demodulated uplink signal exceeds the adaptive threshold amplitude.