AD CONVERTER ARRANGEMENT

摘要

In an AD converter a primary S?-modulator digitizes the analog input signal. The quantization noise generated thereby is isolated in the analog domain and digitized in a secondary S?-modulator. The quantization noise so digitized by the secondary S?-modulator is subtracted from the quantization noise in the output of the primary S?-modulator. Because the quantization noise generated by the primary S?-modulator is subject to filtering (shaping) the quantization noise digitized in the secondary S?-modulator should also be filtered. This is performed by similar filtering in the feedback path of the secondary S?-modulator.