This paper presents a high-speed and high-efficiency capsule endoscopy system. Both a transmitter and a receiver were optimized for its application through an analysis of the human body channel. ON-OFF keying modulation is utilized to achieve low power consumption of the in-body transmitter. A low drop output regulator is adopted to prevent performance degradation in the event of a voltage drop in the battery. The receiver adopts superheterodyne structure to obtain high sensitivity, considering the link budget from the previous analysis. The receiver and transmitter were fabricated using the CMOS 0.13-μm process. The output power of the transmitter is -1.6 dB·m and its efficiency is 27.7%. The minimum sensitivity of the receiver is -80 dB·m at a bit error ratio (BER) of 3 x 10 -6. An outer wall loop antenna is adopted for the capsule system to ensure a small size. The integrated system is evaluated using a liquid human phantom and a living pig, resulting in clean captured images.
Bibliographical noteFunding Information:
Manuscript received July 21, 2011; revised October 10, 2011; accepted December 3, 2011. Date of publication December 28, 2011; date of current version March 21, 2012. This work was supported by the Korea Ministry of Knowledge Economy through the Intelligent Microsystem Center (IMC). Asterisk indicates corresponding author.
All Science Journal Classification (ASJC) codes
- Biomedical Engineering