Frequency transformations on low roundoff noise digital filter realizations

A comparison is made of roundoff noise power of Butterworth, Chebyshev, and elliptic low-pass, bandpass, and bandstop digital filters realized in parallel and cascade forms (optimal against direct second-order sections) and implemented with fixed-point and floating-point numbers. The authors only compare l/sub 2/-scaled structures. It is found that both numerical representations have similar noise-to-signal ratios, taking into account similar overflow probabilities and the same register wordlengths.<>