Design of Cut Off-Frequency Fixing Filters by Error Compensation of MAXFLAT FIR Filters

Maximally-flat (MAXFLAT) finite impulse response (FIR) filters often face a problem of the cutoff-frequency error due to approximation desired frequency by some closed-form solution. So far, there have been plenty efforts design such filter with an arbitrarily specified cut off-frequency, but this type requires extensive computation and is not MAXFLAT anymore. Thus, computationally efficient effective needed for highly accurate characteristics. This paper describes new method designing cutoff-frequency-fixing FIR through compensation filters. The proposed provides Chebyshev polynomial containing cutoff-error function, which can characterize “cutoff-error-free” in terms degree flatness given order off-frequency. also allows formula directly determine flatness, so that has flat magnitude characteristic both passband stopband. remarkable effectiveness efficiency accuracy clearly demonstrated various examples, indicating cutoff-fixing exhibit amplitude distortion less than 10−14 no off-frequency error. approach shown provide significant advantages over previous works flexibility accuracy.