Second-Order Filtering

Each second-order stage (stage number ) has two reverse coefficients and three forward coefficients .

The total number of reverse coefficients is 2Ns and the total number of forward coefficients is 3Ns. The Reverse Coefficients and the Forward Coefficients array contain the coefficients for one stage followed by the coefficients for the next stage, and so on. For example, an IIR filter composed of two second-order stages must have a total of four reverse coefficients and six forward coefficients, as shown in the following equations.