# Crate biquad[−][src]

# biquad

`biquad`

is a library for creating second order IIR filters for signal processing based on
Biquads. Both a
Direct Form 1 (DF1) and Direct Form 2 Transposed (DF2T) implementation is
available, where the DF1 is better used when the filter needs retuning
online, as it has the property to introduce minimal artifacts under retuning,
while the DF2T is best used for static filters as it has the least
computational complexity and best numerical stability.

# Examples

fn main() { use biquad::*; // Cutoff and sampling frequencies let f0 = 10.hz(); let fs = 1.khz(); // Create coefficients for the biquads let coeffs = Coefficients::new(Type::LowPass, fs, f0, Q_BUTTERWORTH).unwrap(); // Create two different biquads let mut biquad1 = DirectForm1::new(coeffs); let mut biquad2 = DirectForm2Transposed::new(coeffs); let input_vec = vec![0.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0]; let mut output_vec1 = Vec::new(); let mut output_vec2 = Vec::new(); // Run for all the inputs for elem in input_vec { output_vec1.push(biquad1.run(elem)); output_vec2.push(biquad2.run(elem)); } }

# Errors

`Coefficients::new(...)`

can error if the cutoff frequency does not adhere to the
Nyquist Frequency, or if the Q value is
negative.

`Hertz::new(...)`

can error if the frequency is negative.

# Panics

There are no panics in the library.

## Re-exports

`pub use coefficients::*;` |

`pub use frequency::*;` |

## Modules

coefficients |
## coefficients |

frequency |
## frequency |

## Structs

DirectForm1 |
Internal states and coefficients of the Direct Form 1 form |

DirectForm2Transposed |
Internal states and coefficients of the Direct Form 2 Transposed form |

## Traits

Biquad |
The required functions of a biquad implementation |