UPSAMPLING/INTERPOLATION AND TIME ALIGNMENT MECHANISM UTILIZING INJECTION OF HIGH FREQUENCY NOISE

摘要

A novel and useful apparatus for and method of upsampling/interpolating a discrete-time input sample stream with time alignment utilizing the addition of randomized high frequency noise. The upsampling mechanism is an effective implementation of a second order interpolator that eliminates the need for a conventional filter as the filtering action is effectively built into the mechanism. The upsampling mechanism takes the derivative of the discrete-time input sample stream, thereby effectively providing another order of interpolation over a conventional interpolator. Before outputting the interpolated signal, an integrator takes the integral of the interpolated samples. Any processing performed between the derivative and integrator blocks effectively provides an additional order of interpolation. High frequency noise (i.e. dithering) is added to the differentiated samples in order to eliminate the spectral regrowth spurs that would otherwise appear in the output after rounding. Delay alignment is performed on the differentiated samples in order to time align both phase/frequency and amplitude samples that are processed on different paths.