A Delta-Sigma modulator that allows for a reduction in the oversampling ratio
(OSR)
of a radio frequency (RF) Analog to Digital Converter. The modulator comprises
a 1-bit quantizer, a N-bit quantizer and a digital quantization error correction
circuit that corrects a for quantization error by using digital output signals
from the 1-bit quantizer and from the N-bit quantizer, and reduces the quantization
noise when the modulator transforms an analog input signal into the digital output
signal. The quantization noise is reduced by ditigally correcting quantization
errors, which affect the signal-to-noise ration (SNR) characteristic, using digital
output signals of the multi-bit quantizer and the 1-bit quantizer. Also, a DC offset
which may be generated by the multi-bit quantizer can be digitally removed.
