Versatile high performance digital SQUID electronics

The digital SQUID Electronics DSE32 has been developed to perform software gradiometry with SQUID magnetometers in multi-channel systems using both High-T/sub c/ and Low-T/sub c/ SQUIDs. A low-noise preamplifier is followed by a fast hybrid feedback-loop, combining the bandwidth of an analog feedback-loop with the accuracy of a digital loop. By resetting and counting of flux quanta in the SQUID, the dynamic range has been substantially increased. All parameters of SQUID and electronics are firmware controlled and allow for auto-setup and tuning. Data are transferred with a rate of 20 Mbit/s by means of noise-minimizing, bi-directional optical fiber. Low power consumption allows the use of a battery, further reducing external noise pick-up. The electronics layout is designed for multi-channel applications, as needed in biomagnetic systems.