Method and apparatus for compensating for variations in magnetic flux supplied to a squid superconducting loop input coil by applying a modulated signal to a modulation coil thereof

摘要

A constant bias voltage is applied to plural superconducting quantum interference devices which are interconnected in parallel. Output currents from the superconducting quantum interference devices are supplied in added condition. Maximal-sequence codes are modulated by a modulation current corresponding to each device, and the modulated maximal-sequence codes are supplied to the modulation coil of each corresponding superconducting quantum interference device. The added output current is demodulated for each device by a maximal-sequence code which is phase shifted by the same quantity as the maximal-sequence code for modulation for each device.