GB806457A - Shifting registers - Google Patents

Abstract

806,457. Pattern-movement stepping registers. INTERNATIONAL BUSINESS MACHINES CORPORATION. Nov. 18, 1955 [Nov. 19, 1954], No. 33070/55. Class 106 (1). A shifting register comprising a plurality of cascade connected electrical triggers is characterized in that in shift operations shifting pulses are only applied to those triggers that have to change their states. This is achieved by applying the shift pulses " sync," Figs. 3, 4, each of which appears in inverted form on lines 24 and 26, to the triggers (Fig. 1, not shown), via diode gates each of which is effective to pass either a positive or a negative shift pulse if the states of the two adjacent triggers are different. Consider for example the coupling between triggers T1 and T2 during the third time period shown in Fig. 4, which extends from sync pulse 2 to sync pulse 3. During this period trigger T1 is on, its output terminal 18 is at +25v, and trigger T2 is off, its terminal 18 being at - 25v and its inverse output being at +25v. Thus the potential of the common point of the two diodes 25, 27 is also +25v. However, on the occurrence of the third sync pulse this point is clamped to zero potential by the action of the diodes, and thus a negative pulse is transmitted to trigger T2 to put it on. Had trigger T2 been on initially then the potential of its inverse output would have been - 25v, the junction of the diodes would have been at zero volts, since resistors 19 and 21 are equal, and on the occurrence of the third shift pulse the junction of the diodes would remain at the same potential and no pulse is passed to trigger T2. In further embodiments, each trigger has a double diode gate, as in Fig. 3, attached to both sides (Fig. 8, not shown), and a number of such triggers are used in Fig. 9 as a reversible shifting register-the shift leads that are not being used being clamped to zero volts-and in Fig. 10, as a two dimensional matrix store with provision for shifting vertically and horizontally. A similar store, but of n-dimensions, is also described (Fig. 19, not shown). Further registers are also described with means for complementing, for parallel entry of data, and for reversing the order of the digits in the register (Figs. 17, 6 and 18 respectively, not shown). Each trigger could employ point contact transistors in place of triodes (Fig. 16, not shown).