Dual quantization continuous time ΣΔ modulators with spectrally shaped feedback

A new technique is proposed to eliminate the nonlinear error of a multibit digital-to-analog converter (DAC) used in a sigma-delta modulator where the solidity of multibit DAC against the clock jitter is reserved. By using dual quantization, this technique reduces the bit length of DAC to one bit and consequently eliminates its nonlinear error. A low-pass finite impulse response (FIR) filter with pseudo digital implementation is merged with this 1-bit DAC to improve its solidity against the clock jitter up to the conventional multibit DACs.