Parallel input, with channels energized randomly, to parallel output, with channels energized in preferred order means, and same in input of numerical-to-digital code converter

摘要

866,215. Multi-stable-state circuits. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Aug. 7, 1958 [Aug. 13, 1957], No. 25590/57. Class 40(6) [Also in Group XIX] An electrical calculating device includes two cascades of resistors fed from separate constantcurrent supplies, a plurality of input means each arranged to raise the potential of the whole of one cascade by an increment of voltage, and to lower the potential of the other cascade correspondingly, and output means for detecting the polarity of the potential difference between selected pairs of points on the cascades. In the circuit shown, negative "1"-representing signals applied to any of input terminals T1-T7 switch over conduction from the left to the right side in an associated double triode V1-V7. Each such switch-over causes an increment of potential to be added at point X and subtracted at point Y, this operation being speeded up by assisted cathode follower circuits V8, V9 and V8SP1/SP, V9SP1/SP. The points X, Y are connected through cascades of resistors as shown to constant current valves V10, V10SP1/SP respectively, whereby for every change in potential at X and Y corresponding changes will be produced at every point in each cascade. Corresponding points in the two cascades are connected to the control grids of long-tailed pairs of pentodes V11, V11 to V17, V17SP1/SP. For zero input, when all the valves V1-V7 are conducting on the left, pentodes V11SP1/SP-V17SP1/SP are conducting. If, however, one of the valves V1-V7 is switched over by a "1" input, the potential applied to the grid of V11 will be higher than that applied to V11SP1/SP so that conduction is switched. Similarly, for two "1" inputs, conduction will be switched in the first two pairs V11, V11SP1/SP and V12, V12SP1/SP, and so on, whereby for seven "1" inputs, all the pentode pairs will be switched over and V11-V17 will conduct. The circuit may be employed in a binary adder (see Group XIX), or for coding (see Group XXXVIII) in which case valves V1-V7 may be weighted by varying the cathode resistances. Specification 717,114 is referred to.