Receiving, decoding and noise limiting systems for a new pressure-sensitive ingestible radio telemetric capsule

A new pressure-sensitive radiotelemetric capsule for recording intraluminal pressures within the human gastrointestinal tract has been developed; this capsule employs a pulsed mode of operation. Data recording as a pulse train greatly simplifies problems encountered hitherto in this field, but has produced the requirement for a decoding system which, on tape replay, will reproduce the original pressure change. A system is described here which, in addition to producing an analogue signal from the recorded pulse train, will also eliminate artefacts due to either spurious radio signals or variations in magnetic tape transport speed; it also provides a sensitive and accurate indication of transient signal loss.