Digital Filter Design Using Non-Uniform Sampling

In this paper, a non-uniform sampling algorithm is proposed for one-dimensional bandlimited time varying signals. The main feature of the proposed sampling scheme is that the sampling steps are inversely proportional to signal gradient or slope of the signal. As a result, a smaller sampling step is obtained whenever the gradient is high and vice-versa. Thus, a better representation of the signal is obtained when it is linearly interpolated between the samples. The proposed sampling algorithm is then applied to the design of digital lters using the well-known impulse invariance method. It is shown that the nonuniform sampling allows to design a FIR lter whose length is 14 times shorter than what is obtained with uniform sampling; with both lters having similar characteristiscs. Simulations are provided to show the performance and characteristics of the sampling sequence.