Magnetic core integrator

THIS PAPER reports the results of studies on improving the characteristics of storage integrator cores used to enhance target detection capability in Doppler radar systems. The cores integrate the total spectral output (reflected signals plus noise) of the radar receiver, effectively summing only those repetitive reflected signals (target echoes) above a predetermined threshold. The cores in use at the beginning of these studies did not integrate ideally, even over a 10-msec (millisecond) integration period, but they represented an improvement over what could be achieved practically with other types of integrators. The cores serve as envelope detectors (amplitude demodulators) and, also, perform the initial data organization requirements for presentation at a computer interface. Performance of this multiple function imposes unusual requirements on the integrator core, but a unique solution, using magnetic tape-wound cores, was proposed.
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The envelope detection is performed by utilizing the variable threshold characteristic of metallic tape-wound cores. Data organization advantages, such as easy access and selection, are inherent in magnetic-core wiring schemes, and the signal integration characteristic is satisfied through the use of specially annealed 50% Ni−50% Fe cores of ultrathin tape which exhibit a progressive magnetization tendency under appropriate drive conditions. The purpose of this paper is to present detailed information on the method evolved for testing integrator cores and give new results on extending the usable integration time to 50 msec.