Abstract: An apparatus is disclosed that provides an implantable sensor assembly configured with signal conditioning circuitry positioned between a sensor and connector to form a unitary liquid impervious flexible structure. The connector is adapted to be detachably connected to an implant service unit, which service unit provides battery power, control functions and wireless communication with a base station. The sensor unit is modular in nature and allows for easy exchange with the implant service unit and other sensors.

Abstract: An implantable, multichannel pulsed-Doppler biotelemetry system is described that uses novel power management techniques to minimize power consumption to very low levels, thus, making such system suitable for long term implantation. A first power management technique described in this invention is implemented as a Closed-loop Doppler flowmeter hardware with adjustable pulse repetition rate (PRF) circuits based on a feedback circuit. Another power management technique used in the system described in this invention is implemented as a PRF-synchronized ultrasonic transducer excitation power supply. Finally, another power management technique is implemented as an adaptive sub-sampling multiplexing that enables multiple channels of flow measurement using only a single flowmeter and acquires the blood flow signal at significantly lower rates than typical Doppler flowmeters.