An empirical mode decomposition (EMD) based algorithm is proposed for mattress-type physiological monitoring. Fast Fourier Transform (FFT) is executed for the mixed physiological signal to estimate the frequency range of the respiration signal and heartbeat signal. Then the physiological signal is decomposed into several IMF components by EMD method, some of which are used to reconstruct the respiration signal and the heartbeat signal, according to the respiration or heartbeat spectrum energy in proportion of the total spectrum energy. The experiment result shows that the accuracy of measured respiration rate and heartbeat rate are both over 90%, compared with the polysomnography.

The authors present a security-enhanced UHF RFID (radio-frequency identification) transponder with novel demodulator. The demodulator, which takes advantage of the rectifier’s first stage as the envelop detector, dosen’t need a separate envelop detector. A novel average detector is also designed, which generates an output voltage having large voltage difference with the envelop signal, making the design demand for the comparator less rigorous. Because the DC level of the envelop signals can vary significantly with the distance between transponder and reader, the comparator is designed to have rail-to-rail common mode input range. To ensure a security communication between transponder and reader, a 128-bit advanced encryption standard (AES) algorithm is employed in the baseband processor. The whole transponder chip is implemented in 0.18μm CMOS process with a die size of 880μm × 950μm. Measurement results show that the minimum input RF signal that can be demodulated is 100 mV and the maximum input data rate is 160 kb/s.