Patent ID: 6999014

Claim:
A method of converting an analogue input signal to a digital output signal by incremental-delta conversion in which, at clock intervals, a quantizer produces digital quantizer signals, a digital-to-analogue converter produces analogue quantizer signals that are a function of said digital quantizer signals, an integrator is responsive to integrator reset signals to produce integrator signals that are integrals with time of said analogue quantizer signals since said reset signals, a feedback loop applies to said quantizer analogue difference signals that are a function of a feedback loop gain and of a difference between said input signal and said integrator signals, and said digital output signal is produced as a function of a sum of said digital quantizer signals since said reset signal; wherein said quantizer is a non-uniform quantizer in which said digital quantizer signals have a first magnitude if said analogue difference signals present a magnitude smaller than a threshold magnitude and a second magnitude, substantially greater than said first magnitude, if the magnitude of said analogue difference signals is greater than said threshold magnitude, said threshold magnitude being substantially less than the magnitude of said analogue quantizer signals corresponding to said second magnitude, and said analogue difference signals changing between two successive clock cycles by a magnitude that is substantially less than the magnitude of the corresponding analogue quantizer signals, so that the gain of the feedback loop from said digital-to-analogue converter to said quantizer is substantially less than one.