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Design >> RF Design >> A basic question on sigma-delta modulator
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Message started by steven on Mar 1^st, 2006, 9:15pm

Title: A basic question on sigma-delta modulator
Post by steven on Mar 1^st, 2006, 9:15pm

Hi,

I think this question is very basic but I am new to this field.

The question is about digital sigma-delta modulator (SDM) in fractional-N synthesizer. The SDM takes K-bits input and output N-bit to the divider (K>=N). What is the contribution of the N-bit SDM output? I mean, since K>N, then the divider could simply use the K-bit. This digital-in-digital-out setup confuses me.

Thanks.