Miniature telemetry systems

A simplex telemetry system is employed for the transmission using straightforward modulation schemes such as amplitude modulation, on-off keying, amplitude-shift keying, and phase-shift keying [101-103]. Because the physiological signals vary slowly, such modulation schemes are preferable for miniaturized and low-power wireless biosensors. 

In an effort to reduce the noise problems often encountered during in vivo type measurements (which limit the reliability of the final determination), telemetry-type systems have been proposed (Bl). In this approach the implanted catheter is connected to a miniature radio transmitter which transmits the in vivo ISE cell potentials to a receiving unit placed far from the patient or animal. By replacing the wires normally required to transmit the potential information to the external instrument, far less interference from environmental and electrical noise normally found in rooms used for surgical procedures occurs. This approach appears to hold great promise for the future of in vivo ion and gas monitoring with ISEs. 

R.D. Beach, R.W. Conlan, M.C. Godwin, et al, Towards a Miniature Implantable in Vivo Telemetry Monitoring System Dynamically Configurable as a Potentiostat or Galvanostat for Two- and Three-Electrode Biosensors, IEEE Transactions on Instrumentation and Measurement, vol. 54, no. 1, pp. 61-72, 2005. 

McMahon C, Mitchell AZ, Klein JL et al (2010) Evaluation of blood pressure measurement using a miniature blood pressure transmitter with jacketed external telemetry in Cynomolgus monkeys. J Pharmacol Toxicol Methods 62 127-135 Misra A, Ganesh S, Shah SP (2003) Drug delivery to the central nervous system a review. J Pharm Pharm Sci 6 252-273... 

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