Patent ID: 7129874

Claim:
An analog-to-digital converter system for converting an analog input signal to a digital output signal, the system comprising: a first stage analog-to-digital converter circuit adapted to convert the analog input signal into a first stage digital output; a digital signal generator adapted to generate a digital test signal, wherein the digital signal generator is further adapted to change an amplitude of the digital test signal based on at least one of a polarity and an amplitude of the analog input signal; a combiner coupled to the first stage analog-to-digital converter circuit and adapted to combine the digital test signal with the digital output of the first stage analog-to-digital converter circuit; a residue signal generator adapted to receive the output of the combiner and to generate a residue signal using the output of the combiner and the analog input signal; a noise shaping circuit adapted to noise shape the residue signal; a sampling circuit coupled to the output of the noise shaping circuit and adapted to sample the noise shaped residue signal; a second stage analog-to-digital converter circuit coupled to the output of the sampling circuit and adapted to generate a second stage digital output based on the sampled residue signal; and a digital correction circuit coupled to the output of the first stage analog-to-digital converter circuit and to the output of the second stage analog-to-digital converter circuit and adapted to combine the first stage digital output and the second stage digital output using a reconstruction filter.