Filtering > a first order MA filter

Digital filters can operate in the space domain by using the convolution product. A sampled signal can be represented by a polynomial of variable z and/or by a set of coefficients. The convolution product of two signals is the product of the polynomials in z domain of these signals. All linear filters can be presented by the relationship between two polynomials in z. A filter for which the polynomial is a fraction, whose denominator is equal to 1, is a moving average filter or MA. The weighted moving average filter is also called a transversal filter. It is currently used to smooth a function. It is a causal filter. In this section, we study the behaviour of a first order MA filter.