The method proposed in this paper can be successfully used for the design of the digital FIR full-band differentiator of arbitrary order. It involves the approximation of the FIR digital differentiator frequency response directly in the complex domain, and represents properly modified eigenfilter method. Introduction of the condition that specification parameter of the group delay level τ has a non integer value allows this method to use the same design procedure and formulas for differentiators with both even and odd length, with very small passband magnitude approximation error and approximately constant passband group delay level. These characteristics are enabled due to the fact that differentiators, designed by the presented method, possess neither the (anti)symmetric feature of impulse response coefficients, nor the strictly linear phase.

Keywords: Digital finite impulse response (FIR), full-band differentiator, Differentiation order, Differentiator length, Magnitude response, Group delay response