INTERPOLATION BY IRRATIONAL FACTOR

The paper presents an interpolation method that can be used for implementing any sampling rate conversion ratio. The interpolator is basically a resonator-based digital filter (RBDF) with special decoupling that requires the computing of sine/cosine functions at arbitrary arguments. The resulting filter has a finite duration impulse response (FIR), but it cannot be designed by the commonly used Parks-McClellan algorithm because the filter response is a finite Fourier polynomial in the time-domain and not in the frequencydomain. A special windowing technique or linear programming can be used to design such filters. A design example, its simulation as well as a digital signal processor based realization are also presented