Stochastic analog-to-digital conversion using asynchronous sampling

An indirect analog-to-digital converter based on a stochastic process using asynchronous sampling of a triangular waveform is presented. The converter features high simplicity, both in conversion principle and circuit design, as the linearity merely depends on short-term stability of nonprecision components. The accuracy increases with the number of samples and a tradeoff is possible between accuracy and conversion time. In the realized converter, three measurements per second can be performed with a 0.2% inaccuracy using a 6-MHz sampling clock, a 20-kHz triangular waveform, and a 21-bit counter. The advantages of the converter will be predominant in applications where conversion time is less important than simplicity and only moderate accuracy is required.<>