A wideband OOK receiver for wireless capsule endoscope

An on-off keying (OOK) receiver for wireless capsule endoscope application is presented, which comprises low-noise amplifier (LNA), band-pass filter, envelope detector, automatic-gain control (AGC) and output buffer. The common-drain-feedback LNA provides wideband input matching. Moreover, a high-frequency envelope detector has been implemented, which is based on OTA-rectifier-peak-detector open loop structure. The storage capacitor of the envelope detector is optimized to obtain good sensitivity and high data rate. A discrete-step AGC is applied for wide input dynamic range, which adopts forward gain-control technique to enhance the settling speed. The carrier frequency is 480 MHz. Sensitivity of the proposed receiver is measured to be -83 dBm, -81 dBm and -80 dBm with data rates of 10 Mbps, 20 Mbps and 40 Mbps, respectively.