| 摘要 |
An approach is presented for relaxing the oversampling requirements in a DELTA SIGMA modulator based analog-to-digital converter through parallel DELTA SIGMA modulation channels with decimation filtering and modulation by sequences ur(n) and vr(n) derived, for example, from an MxM Hadamard matrix. By combining M DELTA SIGMA modulators, each with an oversampling ratio of N, an effective oversampling ratio of approximately NM is achieved with only an M-fold increase in the quantization noise power. In the special case of N=1, full-rate analog-to-digital conversion is achieved. The individual DELTA SIGMA modulators can be any selected from a large class of popular DELTA SIGMA modulators. Unlike most other approaches to trading modulator complexity for accuracy, the system retains the robustness of the individual DELTA SIGMA modulators to circuit imperfections.
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