Continuous-time mash sigma-delta analogue to digital conversion

摘要

A continuous-time MASH sigma-delta analogue-to-digital converter ADC. The ADC may include first and second modulators and an output stage. The ADC may be provided with a first modulator with 1.5 bit and a second modulator with 1 bit each receiving also the feedback from the other modulator. Sampling is at higher rate at the second modulator and decimation is performed before summing its output to the output of the first modulator.

主权项

1. An analogue-to-digital converter, ADC, comprising:
a first continuous-time, CT, delta-sigma, ΔΣ, modulator comprising a first analogue stage arranged to generate a first error signal dependent on an input signal, a first feedback signal and a second feedback signal, a first quantiser arranged to generate a first quantised signal by quantising the first error signal into at least three levels at a first sample rate, and a first digital-to-analogue converter, DAC, arranged to generate the first feedback signal from the first quantised signal; a second, first order CT ΔΣ modulator comprising a second analogue stage arranged to generate a second error signal dependent on the first error signal, the first feedback signal and the second feedback signal, a second quantiser arranged to generate a second quantised signal by quantising the second error signal into two levels at a second sample rate, and a second DAC arranged to generate the second feedback signal from the second quantised signal; and an output stage arranged to generate an output signal by summing the first quantised signal and the second quantised signal.