DSP implementation of arbitrary sampling frequency conversion for high quality sound application

A revision of the Ramstad hybrid structure which uses the B-spline function as analog resampler is presented. The effectiveness of the method is shown implementing a real-time conversion between the standard frequencies of digital audio using a single-chip solution. It is demonstrated that the B-spline functions give higher performances together with a reduced computational complexity. To achieve the required attenuation of 100 dB in the stop band, a B-spline of order six is used in place of a Lagrange polynomial of order nine, which needs about 50% of the multiplications and additions when the fast computation strategy suggested is used. The hybrid structure has been implemented on the Motorola 56001 digital signal processor (DSP)