Enhanced telemetry system using CP-QPSK Band-Pass modulation technique suitable for smart pill medical application

Abstract

A new approach of continuous phase QPSK BandPass modulation technique is being developed as enhancement to the QPSK modulation scheme for inductive data transmission (NFC). The modulation is based on Gaussian filtering of the phase transition from one state to the other rather than discontinuity in phase shift. The carrier is based on low frequency 115 KHz suitable for human body energy penetration due to its large skin-depth and lower inductive power attenuation. The complete signal processing is done digitally, external coil and capacitor is used for transceiver interface. The telemetry assists a smart pill swallowed by human being to trigger an actuator for drug delivery, record temperature, or perform diagnostic task inside the body. The smart pill includes 32bit processor, 16 Kbyte memory, temperature sensor, telemetry unit, and additional external peripheries. The complete system is designed, embedded in one SoC, and realized on ASIC with chip-area less than 14 mm².