Patent GB-977539-A (GB)
Title: Improvements in or relating to parametric devices
IPC: G11C19/12
Filed: 1961-08-29
Abstract: 977,539. Parametrically excited resonators. INTERNATIONAL BUSINESS MACHINES CORPORATION. Aug. 29, 1961 [Aug. 29, 1960], No. 31115/61. Heading H3B. A thin film magnetic element is used in a parametron. Parametrons are continuously excited by a pumping frequency but can be disabled by direct current controls which detune them to suppress the subharmonic oscillation. Information is transferred between adjacent parametrons by stray magnetic fields when the parametrons are tuned to the same natural frequency. Oscillations are transferred from a first to a second parametron without change of phase when the second parametron is tuned downwards to the subharmonic frequency from a higher frequency. Oscillations are transferred with phase reversed if the second parametron is tuned upwards from a lower frequency. Parametron construction.-A thin magnetic film 3 which may be of iron nickel alloy is deposited on a glass support 2. The film and the backing are sandwiched between strip conductors 4, 5 in a circuit terminated by an impedance 8 to avoid reflection. Direct current bias and a pumping frequency are supplied by a battery 7 and a generator 6. The magnetic layer has a natural frequency which can be adjusted by means of the direct current bias. The film may be anisotropic. Under control of the pumping frequency the magnetic reactor M oscillates about a mean position as shown in Fig. 5. Permanent magnets may be used to provide fixed components of the tuning fields. Transfer of information.-Two film elements 30, 31, Fig. 5, on a common support 32 are continuously excited by a pumping frequency on strip conductors (not shown) the magnetic effect of the pumping frequency being indicated by Hp. The two elements have an easy direction of magnetization Ha. Direct current control windings 33, 34 are used to apply magnetic fields to the elements. A field Hg tunes an element to a frequency #r which is a subharmonic of the pumping frequency and a field Hg Œ #Hg detunes the element so that substantially no subharmonic is generated. If element 30 oscillates in phase 1 and if element 31 is disabled by a control field Hg + #Hg, reduction of the control field on element 31 to Hg permits this element to oscillate in phase 1. If, however, the element 31 is disabled by a field Hg - #Hg and this field is increased to Hg, the element oscillates in phase 0. Shift register.-A chain of parametrons A, B, C, B<SP>1</SP> is controlled by conductors A 1 , B 1 , C 1 , B 1 <SP>1</SP>, Fig. 8. A cycle of pulses, shown in Fig. 9, steps information from element A of a first group I to element A of a second group II. Element B<SP>1</SP> is detuned to a lower frequency by control lead B 1 <SP>1</SP>, and inverts the information transferred from element A of the second group II. The elements may be arranged in a two dimensional or in a three dimensional matrix, Fig. 10. The information may then be stepped along rows or columns. Logical devices.-A single element 41, Fig. 11, may be controlled by three other elements 40, 42, 43. If element 43 oscillates continuously in phase 1, element 41 will oscillate in phase 1 if either of the signals A, B from elements 42, 40 is 1. Element 41 responds to A or B. If element 43 oscillates continuously in phase 0, element 41 will oscillate in phase 1 only if elements signals A, B on both 1. Element 41 then responds to A AND B.