Second-order IIR peak or resonator filter
[num,den] = iirpeak(w0,bw)
[num,den] = iirpeak(w0,bw,ab)
[num,den] = iirpeak(w0,bw)
turns
a second-order digital peaking filter with the peak located at w0
,
and with the bandwidth at the +3 dB point set to bw
.
To design the filter, w0
must meet the condition 0.0 < w0
< 1.0,
where 1.0 corresponds to π radians per sample in the frequency
range.
The quality factor (Q factor) q for the filter is related to
the filter bandwidth by q
= w0/bw
where ω0 is w0
the
signal frequency to boost.
[num,den] = iirpeak(w0,bw,ab)
returns
a digital peaking filter whose bandwidth, bw
, is
specified at a level of +ab
decibels. Including
the optional input argument ab
lets you specify
the magnitude response bandwidth at a level that is not the default
+3 dB point, such as +6 dB or 0 dB.
firgr
| iircomb
| iirnotch
| iirparameq