Modulated feedback loop analog-to-digital converter

摘要

The analog-to-digital converter receives an analog input signal (x(t)) to produce a digital error signal (y(t)). It comprises a subtractor (1) to calculate the difference between the input signal and a reference signal (Ur(t)), a converter subsystem (2, 3, 4) to produce the error signal from said difference and a feedback loop to produce the reference signal by means of a digital-to-analog converter (5) which delivers a comparison signal (Uc(t)) in response to the error signal. In accordance with the invention, the input signal (x(t)) is assigned a center frequency (f0), the feedback loop comprises a displacement unit (7) for displacing the frequency response of the digital-to-analog converter (5) from the null frequency towards the center frequency (f0), said displacement unit producing the reference signal (Ur(t)) from the comparison signal (Uc(t)).