Digital-to-analog conversion with reduced quantization noise

摘要

A digital-to-analog (D/A) conversion apparatus using a delta-sigma method performs an additional gain control operation in addition to a filtering operation with respect to differential data in a conventional D/A conversion apparatus. The D/A conversion apparatus includes a multiplier for multiplying the differential data output from a differentiator contained in a conventional D/A conversion apparatus and outputting the resultant data, a filter for filtering the differential data and outputting the filtered data and an adder for adding the output data of the multiplier and the filter and supplying the added result to a quantizer. The factor used in the multiplier is properly selected so that smaller quantization noise is generated than that added during quantization in the conventional D/A conversion apparatus. Thus, the D/A conversion apparatus can provide a wider signal passband in comparison to the conventional D/A conversion apparatus, since it generates the relatively smaller quantization noise with respect to the entire passband. As a result, the D/A conversion apparatus provides good performance appropriate for a next-generation audio equipment requiring a higher signal-to-noise ratio. Also, since the D/A conversion apparatus can be realized by modifying the conventional D/A conversion apparatus slightly in hardware, a D/A conversion apparatus having much better performance can be manufactured using a substantially same production cost and process.