| 摘要 |
<p>A delta-sigma modulator which converts analog signals into digital signals and maintains the linear gain relation between the analog and digital signals. The modulator is contrived by applying the over-sampling technique and the delta-sigma technique to a cascade-connected multi-order circuit. A local feedback loop is formed by connecting the output node to the input node of at least one of the succeeding-order integrators provided in the first and succeeding stages of a cascade-connected A/D converter. The local feedback loop monitors the output of the connected integrator and maintains the input levels at the second and succeeding stages by modulating the output of the integrator by local feedback. The succeeding stages are appropriately scaled, and hence the quantization noise produced at the first stage is perfectly eliminated. Noise leaking out from the first stage due to some direct causes does not interfere the digital signals generated by a noise eliminating circuit at all.</p> |
