tf2sos function

Transfer function to second-order sections form

Convert digital filter transfer function data to second-order section form.

tf2sos(b, a)

Arguments

• b: moving average (MA) polynomial coefficients
• a: autoregressive (AR) polynomial coefficients

Returns

A list with the following list elements:

• sos: Second-order section representation, specified as an nrow-by-6 matrix, whose rows contain the numerator and denominator coefficients of the second-order sections:

    `sos <- rbind(cbind(B1, A1), cbind(...), cbind(Bn, An))`, where `B1 <- c(b0, b1, b2)`, and `A1 <- c(a0, a1, a2)` for section 1, etc. The b0 entry must be nonzero for each section.
  

• g: Overall gain factor that effectively scales the output b

   vector (or any one of the input `Bi` vectors).
  

Examples

b <- c(1, 0, 0, 0, 0, 1)
a <- c(1, 0, 0, 0, 0, .9)
sosg <- tf2sos (b, a)

See Also

See also filter

Author(s)

Julius O. Smith III, jos@ccrma.stanford.edu .

Conversion to R by Geert van Boxtel, gjmvanboxtel@gmail.com .