The nonrecursive digital filter has variable coefficients for the purpose
of shifting the frequency response from one characteristic frequency fc1
to another characteristic frequency fc2. The method enables calculating
the coefficients of the nonrecursive digital filter for shifting the
frequency response of the filter from one characteristic frequency fc1 to
another characteristic frequency fc2. The coefficients of a prototype of
the filter are prescribed or calculated for a given sampling frequency,
the continuous time impulse response associated with this prototype is
calculated and the impulse response is sampled at the sampling frequency
fa2=fa1* fc1/fc2. The new coefficients are thereby produced. The filter
can then be operated with the new coefficients at the old sampling
frequency. As an alternative, the new coefficients can be calculated from
the coefficients of the prototype of the filter by interpolating the
values of the continuous time impulse response at an interval of 1/fa2.