High-Pass or Low-Pass Delta Sigma Modulators?
Résumé
In this paper, High-Pass (HP) Delta Sigma modulators are compared
against the traditional Low-Pass (LP) modulators. The objective
of this comparison is to point out the advantages and drawbacks of
the two modulators thereby allowing to choose the most suited for a
given application. The metrics of comparison are the noise floor, power
consumption, surface area and the effect of the non-idealities of all
the basic blocks (i-e Operational Transconductance Amplifier (OTA),
Quantizer, Switches and Clocks). It turns out that HP modulators are
more suited for narrow band applications because of their immunity
against DC-offset and flicker noise. For medium and wide application,
LP modulators are preferred because of their higher robustness against
switch imperfections and clock jitter.