| 摘要 |
Analogue signals at i/p are converted to digital data at o/p by means of a Sigma-Delta modulator comprising a pair of bandpass filters (H1 (S), H2(S)) consisting of an inductor L and a capacitor C in parallel and a series resistor and a feedback loop including DAC 22. The tendency of such a circuit to instability is reduced or eliminated by making small variations in the phase of the clock 1 controlling the feedback pulses relative to the clock 2 controlling the data output pulses. As an alternative, corrections may be made to the feedback pulses by an additional feedback loop providing pulses for correcting the feedback pulses. |
