A
system for measuring and converting to an observer intelligible form an internal physiological parameter of a
medical patient. The invention allows transcutaneous
telemetry of the measured information
intracranial pressure via a
system which includes a patient implanted sensor module and a
processing and display module which is external of the patient and optically coupled to the sensor module via an external
coupling module. A sensor within the implanted module transduces the measured information and a near
infrared (NIR) emitter transmits this
telemetry information when interrogated by the complementary external
coupling module. Alternately, a set of tuned
inductor-
crystal circuits versus
inductor-
crystal comprised in part of a cylindrical
crystal oscillator whose resonant frequency is sensed by a
dipper circuit arrangement is provided. Power for the sensor module is derived inductively through rectification of a transcutaneously-applied high-frequency alternating
electromagnetic field which is generated by a power source within the external
coupling module, in concept much like a conventional electrical
transformer. A computer within the
processing and display module calculates the parameter value from the
telemetry signal and represents this data either in numerical, graphical, or analog format.