Theoretical investigations on the dynamical behavior of a Josephson sampling gate with a balance comparator

The dynamical behavior of a balance sampling gate, consisting of two directly serially connected Josephson junctions and a common shunt resistor, has been investigated by numerical simulations and approximated equations of the resistive shunted junction model. A reduced damping parameter has been found which determines the sampler behavior alone and enables an optimization. A 2.4-ps rise time of the response to a step-function signal predicted by the approximated theory has been verified by numerical simulations. The sampling gate can be driven directly by a room-temperature generator with a rise time of a few hundred picoseconds.