Method and apparatus for a DAC with non-uniform sampling rate

摘要

An apparatus and method is disclosed for a digital-to-analog converter (DAC) system with both uniform and non-uniform sampling rates. The system includes a digital portion in which samples of a set of "N" digital samples are obtained from a digital input stream. Each set of samples is evaluated with various test decimations which may include various combinations of uniform and non-uniform timing intervals between the selected members of each decimation. Each test decimation includes substantially the same number "M" of digital samples where "M" is less than the number of samples "N" in each sample set. Each test decimation is digitally evaluated to determine which is the optimum test decimation. The optimum test decimation exhibits the best fit with the original set of "N" samples using a reduced set of "M" digital samples. This optimum test decimation along with the appropriate timing information is subject to an digital-to-analog conversion, with the corresponding analog output signal retaining a high degree of fidelity with the digital input signal albeit at a reduced average sampling rate. The reduction in sampling rate for the DAC simplifies circuit design and reduces power requirements.