Superconductor Digital-to-Analog Converter based on processing of SFQ pulses

Recently we designed and successfully tested a prototype of a superconducting Digital-to-Analog Converter (DAC) based on processing Single Flux Quantum (SFQ) pulses. Two unique features make the device very attractive for metrology applications: i) The generation of output voltage is based on the fundamentally accurate Josephson frequency-to-voltage relationship. ii) The device does not require any external signals with frequencies higher than 100 MHz. It is expected that the DAC will be used as a key component of novel Standards and Calibrators of ac voltage with frequency up to 1 MHz. The implemented prototype has low magnitude of output voltage (about 10 mV) which is far lower than the 1 to 10 V target magnitude. At the conference we would like to present new results that will be obtained during the first half of 1998.