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For the digital implementation of a biquad filter, check digital biquad filter.
Additional recommended knowledge
A biquad filter is a type of active filter consisting of a two-integrator feedback loop with an inverter. In its basic configuration, it can be used as either a low-pass or band-pass filter, depending on where the output signal is taken from.
For a second-order filter, the low-pass transfer function is given by
and the band-pass transfer function, by
For the topology shown in Figure 1, the filter properties are given by:
The bandwidth is approximated by B = ω0 / Q, and Q is sometimes expressed as a damping constant ζ = 2 / Q.
If a noninverting low-pass filter is required, the output can be taken at the output of the second operational amplifier. If a noninverting band-pass filter is required, the order of the second integrator and the inverter can be switched, and the output taken at the output of the inverter's operational amplifier.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Biquad_filter". A list of authors is available in Wikipedia.|