| 摘要 |
A delta modulator comprising a feedback loop incorporating a cascade arrangement formed by a difference producer, a loop filter, a two-level quantizer, a clock pulse-controlled sampler and a feedback path. In order to optimize the signal/quantization noise ratio the minimum phase loop filter has such a phase characteristic that the phase shift in the feedback loop caused by the time delay of the sampler is replenished to approximately 180 DEG with a certain margin, in a frequency range up to a certain cut-off frequency, the phase of the loop filter being constant above the cut-off frequency.
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