An asymmetrical QPSK/OOK transceiver SoC and 15:1 JPEG encoder IC for multifunction wireless capsule endoscopy

A chipset including a low power asymmetrical QPSK/OOK transceiver SoC and a 15:1 JPEG image encoder IC is presented for wireless capsule endoscopy. The proposed asymmetrical bi-directional telemetry link supports high-data-rate image transmission with QPSK modulation and low-data-rate actuator control data reception with OOK modulation. To transmit high-quality images with high spectral efficiency, a low power JPEG encoder with compression ratio as high as 15:1 is employed to compress raw image data with subsampling technique in YUV color plane. Implemented in 0.18-μm CMOS, the QPSK TX consumes 5 mW at -6 dBm of output power with 3-Mb/s data rate while the OOK RX achieves -60 dBm of sensitivity at 500-kb/s data rate with 6-mW power consumption. A prototype capsule system has been implemented for wireless endoscopy using the developed chipset. With duty cycling, the average power consumption of TX is 2.5 mW when transmitting at 3-fps frame rate.