A three-coincident-current ferrite core analog memory matrix

Abstract

Ferrite cores with rectangular hysteresis loops can store analog values if the flux φ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</inf> , corresponding to the analog input information, is impressed upon the core. All known techniques, however, are applicable only for a single element, but not for a three-dimensional random access matrix because of physical or economical reasons. A new technique for the selection and driving of each core of a matrix for analog storage by three-coincident pulsewidth modulated currents was developed. To achieve the necessary linear relation between the input value and the impressed flux by voltage pulses of constant amplitude, the amplitude of the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</tex> write current pulses is controlled by a reference core, while that of the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</tex> write pulse is regulated. The total error is within ± 1% for all matrix cores. Serial or parallel operation for writing and reading is possible as well as a quasi-nondestructive readout by quantization of the read analog value before rewriting.