Patent ID: 6486811
Filing Date: 2002-11-26
Classification: H03M

Abstract:
An analog-to-digital converter for converting an analog input signal which is present at a signal input and has a specific frequency bandwidth, into an offset-free digital output signal, having:(a) a subtracting unit, which subtracts an analog actuating signal from the analog input signal in order to generate an analog difference signal and amplifies the analog difference signal generated; (b) an analog-to-digital converter circuit having a high clock rate for converting the amplified analog difference signal into a digital difference signal; (c) a digital processing circuit for digital processing of the digital difference signal; and (d) a digital-to-analog converter circuit for converting the digital difference signal processed by the digital processing circuit into the analog actuating signal, wherein (b1) the digital difference signal is the digital output signal of the analog-to-digital converter; (c1) the digital processing circuit performs digital low-pass filtering of the digital output signal; and (c2) the digital processing circuit decimates the digital output signal in order to reduce the clock rate, in which case(c3) the digital processing circuit is arranged in the feedback path of the analog-to-digital converter; and (c4) the digital processing circuit is embodied as a digital clamping circuit and clamps the DC offset value of the digital output signal to a value equal to zero.