Zpg {gsignal}

Zero pole gain model

Description

Create an zero pole gain model of an ARMA filter, or convert other forms to a Zpg model.

Usage

Zpg(z, p, g)

as.Zpg(x, ...)

## S3 method for class 'Arma'
as.Zpg(x, ...)

## S3 method for class 'Ma'
as.Zpg(x, ...)

## S3 method for class 'Sos'
as.Zpg(x, ...)

## S3 method for class 'Zpg'
as.Zpg(x, ...)

Arguments

z

complex vector of the zeros of the model.

p

complex vector of the poles of the model.

g

overall gain of the model.

x

model to be converted.

...

additional arguments (ignored).

Details

as.Zpg converts from other forms, including Arma and Ma.

Value

A list of class Zpg with the following list elements:

z

complex vector of the zeros of the model

p

complex vector of the poles of the model

g

gain of the model

Author(s)

Tom Short, [e-mail],
adapted by Geert van Boxtel, [e-mail].

See Also

See also Arma

Examples

## design notch filter at pi/4 radians = 0.5/4 = 0.125 * fs
w = pi/4
# 2 poles, 2 zeros
# zeroes at r = 1
r <- 1
z1 <- r * exp(1i * w)
z2 <- r * exp(1i * -w)
# poles at r = 0.9
r = 0.9
p1 <- r * exp(1i * w)
p2 <- r * exp(1i * -w)

zpg <- Zpg(c(z1, z2), c(p1, p2), 1)
zplane(zpg)
freqz(zpg)

## Sharper edges: increase distance between zeros and poles
r = 0.8
p1 <- r * exp(1i * w)
p2 <- r * exp(1i * -w)
zpg <- Zpg(c(z1, z2), c(p1, p2), 1)
zplane(zpg)
freqz(zpg)