Asynchronous Sigma-Delta Analog-to-Digital Converter

The paper describes Asynchronous Sigma-Delta Modulator Analog-to-Digital Converter (ASD-ADC) built around the first order ASD modulator. Asynchronous sigma-delta modulator performs asynchronous amplitude-to-time conversion creating 1-bit output sequence which is further sampled by the Time-to-Digital Converter (TDC) and converted into the time-discrete synchronous m-bit words, suitable for further digital signal processing. Proposed ASD-ADC architecture, simulation of its MATLAB^® model and evaluation of its performances are described.