Patent GB-1171120-A (GB)
Title: Microwave Absorption Device.
Inventor: GAMBLIN RODGER LOTIS
IPC: G06F15/18
Filed: 1966-10-21
Abstract: 1,171,120. Circuits employing magnetic storage elements. INTERNATIONAL BUSINESS MACHINES CORP. 21 Oct., 1966 [22 Oct., 1965 (3)], No. 47119/66. Heading H3B. [Also in Division G4] A microwave absorption device comprises a toroid with means for circularly magnetizing it with a selected polarization and associated with a transmission line receiving microwave energy at substantially the gyromagnetic resonance frequency of the toroid, there being means to detect microwave energy propagated along the transmission line. A microwave absorption element comprises a helical coil wrapped around a cylindrical ferrite toroid. A microwave energy having the gyromagnetic resonance frequency of the toroid and applied to the coil will be absorbed to an extent determined by tile sense and (by utilizing the multi-domain structure of the ferrite) average intensity of circular magnetization in the toroid. The magnetization can be set by pulses of fixed or selected polarity in one or more than one (coincident selection) windings threading the toroid, the magnetization retaining the set value until altered by further pulses or until just after the end of the current pulse. Fig. 7 shows a logic network employing a matrix of the absorption elements. Boolean variables A, B, C are applied to wires threading the toroids of the elements 314 in the first three rows to cause the elements to pass or block microwave energy in accordance with the value of either the Boolean variable or its inverse depending on the sense of the threading. The microwave energy is applied to the columns of the matrix from a strip line 304 fed by a Gunn effect or tunnel diode oscillator 302. Each column thus provides an AND function of true or inverse values of the variables A, B, C, and the result from one or more columns is gated by the fourth row of absorption elements 335-342 through directional couplers 352- 359 to a strip line 360 feeding a sense amplifier 362. The gating is controlled by switching network 350 which energizes a line 346 threading all the toroids in the fourth row and one or more further lines 348 &c., each threading a respective one of the toroids in the fourth row. If the outputs from more than one of the columns is gated to the line 360, an OR function of them is thus formed. The output of the sense amplifier 362 may control the switching network 350 or another logic matrix. Another logic network is described producing various combinations of AND, OR and INVERT functions on separate lines, in a generally similar way except that the OR function is produced by simple junctions. Fig. 6 shows a learning network for speech recognition. During learning a pattern generator 192 applies a pattern of " ones " and " zeros " to be recognized to lines 222, each " one " bit enabling a corresponding absorption element 180-184 to pass microwave energy from a strip line 172 fed by a Gunn Effect oscillator 122 to a corresponding column of a matrix of absorption elements 102. The outputs from each row 160, 162, 164 of this matrix are applied via directional couplers 202 to a corresponding strip line feeding a respective decisional amplifier 204, 206, 208. If the threshold of the wrong decisional amplifier is exceeded, pulse generators increment the intensity of magnetization of the toroids of the matrix row which should have caused the threshold of the respective decisional amplifier to be exceeded and decrement the magnetization in the row which incorrectly caused exceeding of its respective threshold. However, this incrementing and decrementing only occurs in positions corresponding to a " one " bit in the pattern, under control of lines 224 from the pattern generator 192. Uniform energy distribution to matrix columns is achieved by tapering the strip line fed from the microwave oscillator and providing impedance mismatches at the junctions with the matrix column lines.