Xiang Jing-lin

Detecting system and power-spectral analysis of pulse signals of human body

In this paper, in the light of three features of the human pulse signal, a non-contact-type detection system is designed, which can be used to detect pulse signals. The signal processing system suitable for the pulse signals is set up. The power spectra of the four kinds of pulse signals are obtained by using the fast Fourier transform (FFT) and the power-spectral characteristics are analyzed and compared. Several important conclusions drawn in this paper may be of great value in the objective study of the pulse-condition and in the noninvasive diagnosis of the cardiovascular system.

Weak signal detection and asymptotic relative efficiency in Gaussian-Exponential mixture noise

Traditional signal detectors for underwater targets are based on Gaussian model. Such model, according to recent research, does not agree with actual ocean ambient noise, and the optimal detector based on this model risks unexpectedly poor performance. We present a Gaussian- Exponential mixture model to describe the received noise by analysis of underwater noise samples for deriving an optimal signal detector. We first rebuild the ocean ambient noise model as a Gaussian-Exponential mixture model. Next, we derive an optimal nonlinear detector structure for known signals in such noise. Finally, in order to evaluate the performance of the optimal detector, it is compared to the conventional energy detector. The comparison is based on the concept of asymptotic relative efficiency (ARE) for comparing hypothesis testing procedures. The simulation results show that the performance of the proposed detector is better than that of the conventional energy detector by 4∼8dB.

Design for underwater platform's attitude data acquisition system based on software radio technology

That the underwater platform rocks constantly in the water will lead to serious bias in the long-range detection to a target. Therefore it is necessary to track and predict the attitude of the swaying platform accurately. This paper introduced an attitude data acquisition system which uses the principle of software radio technology, and can operate steadily for a long time based on a low power electronic compass. Meanwhile, the function that controls the sampling model in the dynamic condition has been verified correctly with the prototype of data acquisition system.