matlab iir sos g含义,IIR biquad digital parametric equalizer filter

Parametric equalizers are digital filters used in audio processing for adjusting

the frequency content of a sound signal. Parametric equalizers provide capabilities

beyond those of graphic equalizers by allowing the adjustment of gain, center

frequency, and bandwidth of each filter. In contrast, graphic equalizers allow for

the adjustment of the gain of each filter only. Digital parametric audio equalizers

are commonly implemented as biquadratic (second-order IIR) filters. Due to low

order, biquadratic filters can present relatively large ripple or transition

regions. When several filters are connected in cascade, they can overlap with each

other. In such circumstances, high-order filters are preferred. High-order filters

provide flatter passbands, sharper band edges, and more control over the shape of

each filter. In addition, if the order of the filter is set to two, the design

changes to a special case: a traditional second-order parametric equalizer.

The figure shows the magnitude response of a second-order parametric equalizer

compared with a high-order parametric equalizer.

W0 =

0.3 × π radians/sample is the center frequency of the

equalizer, BW = 0.2 radians/sample is the

bandwidth of the equalizer, G = 10 is the

peak gain of the equalizer, G0 =

1, and GB =

(G02 +

G2) /

2.