Title :
State space approach to design of continuous time sigma delta ADC with delay in feedback path
Author :
Gupta, Amit Kumar ; Sanchez-Sinencio, Edgar
Author_Institution :
Electr. Eng. Dept., Texas A&M Univ., College Station, TX
Abstract :
Excess loop delay is one of the major factors limiting the performance of continuous time sigma delta modulator (CTM). A solution is to provide an additional feedback path just before quantizer to compensate for this delay. Modified z- transform has been previously used as a technique to design the CTM incorporating the delay. In this paper we extend the work in (R. Schreier and B. Zhang, 1996) and present a state space based method to design such modulators. State space approach is preferred since it helps to automate the calculation of co-efficient using MATLAB. For the modulators with resonators in the loop filter, it is shown that using some results from z-transform techniques greatly simplify the design procedure.
Keywords :
Z transforms; circuit feedback; continuous time filters; delays; mathematics computing; resonator filters; sigma-delta modulation; state-space methods; CTM; MATLAB; additional feedback path; continuous time sigma delta ADC; continuous time sigma delta modulator; excess loop delay; feedback delay; loop filter; modified z-transform techniques; resonators; state space approach; Delay effects; Delta modulation; Delta-sigma modulation; Feedback loop; MATLAB; Resonator filters; Signal to noise ratio; State feedback; State-space methods; Transfer functions;
Conference_Titel :
Circuits and Systems, 2006. MWSCAS '06. 49th IEEE International Midwest Symposium on
Conference_Location :
San Juan
Print_ISBN :
1-4244-0172-0
Electronic_ISBN :
1548-3746
DOI :
10.1109/MWSCAS.2006.381818