Low power 2 Mbps radio telemetry system for biomedical applications

The paper presents a low power telemetry system for neural recording applications. The presented system operates in the 433 MHz ISM band. It offers a 2 Mbits/s throughput using a continuous phase frequency-shift keying (CPFSK) modulation. The presented transmitter is based on a free running, modified complementary Colpitts oscillator. Instead of using a separate power amplifier to drive the antenna, the VCO incorporates a loop antenna as its inductive element. To compensate for the oscillator frequency pulling due to changes in the antenna's environment, supply voltage or temperature, a wide band high performance digital receiver was developed. The presented transmitter was implemented using a 180 nm CMOS process, and consumes just 450 uW.