Error rate of RSFQ circuits: theory

For the first time, the bit-error rate of an active SFQ experiment is compared to theoretical prediction. The theory of thermally induced errors is developed using the Fokker-Planck equation. The equivalent noise temperature of the experiment is found to be 11.0 K. The error rate vs. bias current follows an error function dependence and extrapolates to vanishingly small error rate at optimal bias.