In a method of converting an analog signal to digital format, an analog input signal is received and processed using sigma-delta modulation to provide a first digital signal that represents the analog input signal in digital format and to provide a second digital signal that represents a first error introduced during the sigma-delta modulation. A second error that is error introduced during the sigma-delta modulation is estimated. A pre-correction signal is determined based on the first and second digital signals. A difference between the estimated second error and the pre-correction digital signal is determined to provide a digital output signal representing the analog input signal in digital format. An error correction element operable to adjust the digital output signal based on the analog input signal, the digital output signal, and the second digital signal is controlled.