New Feedback Architecture for VCO-Based Delta-Sigma ADCs Utilizing Phase Shifter

Ali Mohammadi, Ahmad Ayatollahi, Adib Abrishamifar

Research output: Contribution to journalArticlepeer-review


Abstract The voltage controlled oscillator-based (VCO-based) continuous-time delta-sigma (CTDS) analog to digital converter (ADC) suffers from nonlinearity and mismatch in its feedback network. A new feedback network consisting of a phase shifter is proposed. The phase shifter replaces the digital to analog converter (DAC) in the proposed architecture. Feasibility of the proposed idea is discussed and its higher performance is illustrated through a behavioral simulation approach (CppSim). We have also developed the phase shifter as a variable all-pass filter in the C language. The nonlinearity and mismatch of the system caused by DAC is mitigated, resulting in higher signal to noise ratio (SNR) and signal to noise and distortion ratio (SNDR), respectively.
Original languageEnglish
Pages (from-to)281-285
Number of pages5
JournalJournal of Electronic Science and Technology (JEST)
Issue number3
Publication statusPublished - 2012


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