Portability | portable |
---|---|

Stability | experimental |

Maintainer | m.p.donadio@ieee.org |

Safe Haskell | Safe-Inferred |

Module to sharpen FIR filters

Reference: Hamming, Sect 6.6

`H'(z) = 3 * H(z)^2 - s * H(z)^3`

` = H(z)^2 * (3 - 2 * H(z))`

Procedure:

- Filter the signal once with H(z)
- Double this
- Subtract this from 3x
- Filter this twice by H(z) or once by H(z)^2