A Fast Response To Time-varying FIR Digital Filter

Filtering is a basic and important technology in signal processing, the use of filtering techniques can not only extract the desired signal from a variety of signals, but also can effectively filter out unwanted interference signal. With the advent of the digital information age, digital filtering technology has become an extremely important subject and technology. In practical application and production, since the low-frequency weak signals, such as marine monitoring, geological exploration and biomedical areas etc,which usually carry a significant amount of important basic information. The low-pass filter is widely used in information acquisition and anti-noise environments interference design, In addition to constant linear digital filter is widely used, but also we often use a linear time-varying digital filter. For example, we use a filter to filter out signal noise in a communication system, if the input is non-stationary process, so we want to design the optimal filter is linear time-varying filter. In addition, the linear time-varying digital filter is applied in the field of seismic exploration, speech processing, etc.In designing a filter, we not only hope that filter has a good frequency characteristics in the pass band, but also has a fast response. In many applications, the speed of response of the filter system and signal to noise ratio is equally important indicators. However, conventional time-invariant filter implementation is unlikely to satisfy such characteristics. The goal of this article is in research of establishing the time-varying low pass digital filter system theory and the realization method, which aims to provide techniques and theory of reference for practical implementations.The main work and in this article are:(1) in the digital domain, we designed two different time-invariant FIR digital filter, through simulation, one filter has a high signal to noise ratio, and the other has a faster response speed. (2) designing a method to detect whether the signal has devised for location of the mutation. (3) At the basic of time constant of the filter to study time-varying digital filter, so that the speed of response and signal to noise ratio is significantly improved.Simulation results show that the proposed scheme is an effective rapid filtering technology, which have some engineering applications, as used here in, it is a simulation using MATLAB simulation tool derived.