The use of optical sensors is nowadays very common in the area of non-invasive diagnosis. This is mainly because of their salient features like, simple construction, low cost, easy to use, relatively inexpensive nature etc. Photoplethysmography (PPG) sensor is one among the wide variety of optical sensors available, and is used to measure the blood volumetric changes occurring in the various parts of the body. PPG signal contains rich source of information related to cardio-pulmonary system. But the major problem associated with the signal is the motion artifacts, causing corruption in the original PPG signal. The aim of this study is to know in deep about the different parameters of PPG signal. Peak and transition points of the pulse signal are determined as a part of pulse wave analysis. Wavelet transform is now commonly used in a wide variety of signal processing applications. In this work wavelet de-noising is used for removing AWGN from the PPG signal. Various mother wavelets are studied and the performance of them are evaluated based on the cross correlation with the original signal.

In wireless communication, the broadcast nature of the medium has made information security a very important concern. This nature allows the unauthorized receivers to observe and eavesdrop the signals sent by the transmitter to an authorized receiver if it lies within the transmission range. This paper considers the transmit and receive filter design for multiple input multiple output (MIMO) Gaussian wiretap channel. The optimal transmit filter design requires prior knowledge of the type of filters used at the receivers. Here, we assume that the valid receiver and the eavesdropper employ Zero-Forcing (ZF) criteria at their receivers. We also assume that the transmitter, intended receiver and eavesdropper are equipped with two antennas and channel information is known to all parties. The transmit and receive filters are designed with an objective to minimize the mean-square error (MSE) between authenticated parties, while ensuring that the eavesdropper MSE goes beyond a certain level. Performances of the designed filters are analyzed using numerical simulation.