Designs an nth-order Butterworth IIR low-pass or high-pass filter.
The returned coefficients are normalized such that a(1) is one and use the increasing-delay convention required by filter.
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| integer(kind=int32), | intent(in) | :: | n |
The Butterworth filter order. |
||
| real(kind=real64), | intent(in) | :: | fc |
The cutoff frequency, in Hz. |
||
| real(kind=real64), | intent(in) | :: | fs |
The sampling frequency, in Hz. |
||
| real(kind=real64), | intent(out), | allocatable | :: | b(:) |
The numerator coefficients of the designed filter. |
|
| real(kind=real64), | intent(out), | allocatable | :: | a(:) |
The denominator coefficients of the designed filter. |
|
| integer(kind=int32), | intent(in), | optional | :: | ftype |
LOW_PASS_FILTER (default) or HIGH_PASS_FILTER. |