sos2tf function

Sos to transfer function

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

sos2tf(sos, g = 1)

Arguments

• 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). Default: 1.

Returns

An object of class "Arma" with the following list elements:

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

Examples

sos <- rbind(c(1, 1, 1, 1, 0, -1), c(-2, 3, 1, 1, 10, 1))
ba <- sos2tf(sos)

See Also

as.Arma, filter

Author(s)

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

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