Two loop superconducting sigma-delta analog-to-digital converters
US5198815A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 12, 1991 |
| Grant date | Mar 30, 1993 |
| Priority date | — |
| Expiry date | Dec 12, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/43
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A two-loop superconducting sigma-delta analog-to-digital converter includes a first superconducting inductor to which the analog signal is applied. A resistor converts to current in the first inductor to a voltage which is applied to a second superconducting inductor. The current in the second inductor, which increases quadradically with time, is applied to an overdamped Josephson junction which kicks back a single quantum voltage pulse each time its critical current is exceeded. This pulse reduces the current in the second inductor and serves as a digital ONE output. The pulses are also applied to an underdamped Josephson junction in a feedback pulse generator which latches at its gap voltage for the remainder of a half cycle of an ac bias current. This provides a voltage source for the primary of a superconducting transformer having a mutual inductance which produces sufficient flux in the secondary to cause a SQUID to generate in response to each pulse from the quantizer a selected number of feedback pulses which are applied to the first inductor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.