Patent ID: 6275177
Filing Date: 2001-08-14
Classification: H03M

Abstract:
A sigma-delta modulator (SDM) using a local nonlinear feedback loop (LNFL) technique comprising:plural modulation units connected in series, for generating plural modulated signals and plural quantized error signals, wherein the input end of at least one of said modulation units is coupled to an analog input signal, and the input ends of other said modulation units are coupled to said quantized error signals, respectively;a level adjustment unit selectively arranged at the input end of at least one of said other modulation units for determining whether an addition or subtraction of a specified value will be performed to at least one of said quantized error signals in accordance with a signal value of said at least one of said quantized error signals of at least one of said modulation units, and performing in accordance with said determined result a subtraction or an addition of said specified value from or to a modulated signal of at least one of said modulation units, wherein at least one level adjustment unit is arranged in said SDM; andan adder-synthesizer unit coupled to the plural modulation signals generated by said plural modulation units for generating an output signal of the SDM.