ellipap

Create a normalized Elliptic analog lowpass prototype filter in zero-pole-gain form.

Syntax

[z,p,k] = ellipap(n, Rp, Rs)

Inputs

n
The filter order.
Type: integer
Dimension: scalar
Rp
The maximum attenuation in decibels in the passband, at 1 rad/sec.
Type: double
Dimension: scalar
Rs
The minimum attenuation in decibels in the stopband.
Type: double
Dimension: scalar

Outputs

z
The zeros of the filter.
Type: vector
The vector length will be one less than the number of poles when the filter order is odd.
p
The poles of the filter.
Type: vector
k
The gain factor.
Type: scalar

Examples

Create a fourth order Elliptic analog prototype filter, with 1 dB attenuation in the pass band and 20 dB attenuation in the stop band.

[z,p,k] = ellipap(4, 1, 20)
z = [Matrix] 4 x 1
0.00000 + 1.12431i
0.00000 + 2.03909i
0.00000 - 2.03909i
0.00000 - 1.12431i
p = [Matrix] 4 x 1
-0.05161 + 1.00365i
-0.40028 + 0.65090i
-0.40028 - 0.65090i
-0.05161 - 1.00365i
k = 0.1