Digital processing of signals produced by voltage-controlled-oscillator-based continuous-time ADCs

The use of voltage-controlled ring oscillators to implement analog integrators with high DC gain has been recently proposed and successfully demonstrated in analog filters and amplifiers. Such an implementation encodes an analog input in a pulse-width-modulated form. We consider direct processing of such signals with a clockless, event-driven, continuous-time DSP. We demonstrate through simulations that the resulting highly-digital system can have significantly relaxed DSP constraints over ones that encode analog signals using level-crossing sampling, potentially lowering the power dissipation and chip area of the processor significantly. Nonidealities and design considerations are also discussed.