| 1 | = Format of filter files = |

| 2 | |

| 3 | The filter files are line oriented, that means there is one information entry per line. Blank lines are not allowed! The format of the filter files is as follows: |

| 4 | |

| 5 | == FFT filter == |

| 6 | |

| 7 | * All lines at the beginning of the file starting with exclamation sign ! are comments and ignored by the program. |

| 8 | * The first data line is a magic number and must be 1357913578 |

| 9 | * The next data line contains the number 1, which is an ID for FFT filters. |

| 10 | * Normalization value (real number), which is multiplied to the output samples of the filter. |

| 11 | * Number of zeros z (integer) |

| 12 | * z lines following with one zero each in the format (<real-part>,<imag-part>). Both parts of a complex conjugate pair must be specified. |

| 13 | * Number of poles p |

| 14 | * p lines following with one pole each in the same format as zeros. |

| 15 | |

| 16 | [http://www.seismic-handler.org/portal/browser/SH_SHM/trunk/filter/GRFO_S%2BSRO_LP.FLF Example of an FFT filter file]. |

| 17 | |

| 18 | == Recursive filters == |

| 19 | |

| 20 | * All lines at the beginning of the file starting with exclamation sign ! are comments and ignored by the program. |

| 21 | * The first data line is a magic number and must be 1357913578. |

| 22 | * The next data line contains the number 3, which is an ID for recursive filters. |

| 23 | * Sample rate for which this file is valid (real number) |

| 24 | * Normalization value (real number), which is multiplied to the output samples of the filter. |

| 25 | * Number of numerator coefficients n (integer) |

| 26 | * n lines following, one coefficient (real number) in each. |

| 27 | * Number of denominator coefficients d (integer) |

| 28 | * d lines following, one coefficient per line. |

| 29 | * Optional following other stages of the filter, new stage indicated by a line containing a single @. |

| 30 | * Additional stages are repeating the entries 'ID number 3' until denominator coefficients. |

| 31 | |

| 32 | [http://www.seismic-handler.org/portal/browser/SH_SHM/trunk/filter/20HZ_GRSN_S%2BSRO_LP.FLR Example of a recursive filter file]. |

| 33 | |

| 34 | back to [ShmDocIndex documentation index] |