Design of superconducting single flux quantum decimation filters

A third-order sine decimation filter was designed for a /spl Sigma/-/spl Delta/ A/D converter with a second-order modulator. The sine filter was formed from multistage decimation structure, which was constructed from the cascade connection of third-order sine filters with a decimation factor of 2. A counter, consisting of single-flux-quantum (SFQ) toggle flip-flops (TFF) with destructive readout, was used to reduce the circuit scale. The sine filter with a decimation factor of 2, which is the circuit that operates at the highest frequency in a multistage decimation structure, operated up to the clock frequency of 18 GHz in a circuit simulation. A sine filter with a decimation factor of 32 was calculated to require 6700 Josephson junctions that consume 1.9 mW.