Properties of approximate Parks-McClellan filters
Li Lee, Alan V. Oppenheim · 2002
It has been observed empirically that each coefficient in a Parks-McClellan filter converges to a steady state value as the filter length increases. This suggests the possibility of obtaining filters that are near optimal while "re-using" filter coefficients from shorter filters in the design of longer filters. In the context of approximate processing this then allows a filtering operation to be done in stages. This paper demonstrates this observation and examines some of its implications.