Linear Josephson Sampler
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Sampling by means of a pulse generator and an in-line gate comparator makes possible the measuring of waveforms of high speed, low temperature Josephson devices without the need for a feedback circuit. Fig. 1 shows the sampler circuit, made up of a pulse generator 1 and an in-line gate comparator 2, which has a linear threshold region. (An asymmetric two-junction interferometer can also be used since it has a linear region in the threshold curve like the in-line gate.) An in-line gate threshold curve is shown in Fig. 2 with the pulse and waveform to be measured. The pulses from the pulse generator 1 are narrow (N20 ps) with a frequency of about 10 MHz. The gate current Ig is ramped at the rate of about 1-10 KHz so that the gate current ramp is sampled between 1,000-10,000 times by the pulse.