invimpinvar function

Inverse impulse invariance method

Convert digital filter with coefficients b and a to analog, conserving impulse response.

invimpinvar(b, ...)

## S3 method for class 'Arma'
invimpinvar(b, ...)

## Default S3 method:
invimpinvar(b, a, fs = 1, tol = 1e-04, ...)

Arguments

• b: coefficients of numerator polynomial
• ...: additional arguments (not used)
• a: coefficients of denominator polynomial
• fs: sampling frequency (Default: 1 Hz)
• tol: tolerance. Default: 0.0001

Returns

A list of class Arma containing numerator and denominator polynomial filter coefficients of the A/D converted filter.

Details

Because invimpinvar is generic, it can also accept input of class Arma.

Examples

f <- 2
fs <- 10
but <- butter(6, 2 * pi * f, 'low', 's')
zbut <- impinvar(but, fs)
sbut <- invimpinvar(zbut, fs)
all.equal(but, sbut, tolerance = 1e-7)

References

Thomas J. Cavicchi (1996) Impulse invariance and multiple-order poles. IEEE transactions on signal processing, Vol 40 (9): 2344--2347.

See Also

impinvar

Author(s)

R.G.H. Eschauzier, reschauzier@yahoo.com ,

Carne Draug, carandraug+dev@gmail.com .

Conversion to R by Geert van Boxtel, G.J.M.vanBoxtel@gmail.com