Capacitor sample and hold circuit employing singal comparison and regeneration

摘要

981,164. Electrostatic digital data storage apparatus. F. H. SHEPARD. May 19, 1961 [May 19, 1960], No. 18390/61. Heading G4C. [Also in Division H3] In a memory circuit, a number is remembered by charging a capacitor to a corresponding voltage level, comparing this remembered voltage with a voltage staircase, deriving a pulse at the instant when the two voltages are equal and using this pulse to actuate an electronic switch which applies to the capacitor a voltage equal to the voltage to be remembered. As described, 64 numbers are given an octal coding and the two voltages representing each number are stored in a coarse memory capacitor 122 and a fine memory capacitor 102. Considering the fine level circuit, valves 114, 116 are momentarily cut off to render valve 106 conducting, thus connecting the "fine level" input 110 to capaciter 102. The potential across capaciter 102 is then compared with the "fine staircase" voltage in circuit 140, 142 which produces an output pulse to cut off valve 154 when ever the staircase voltage exceeds that being remembered. A similar circuit cuts off valve 160 when the "coarse" staircase voltage exceeds the voltage stored in capacitor 122, and when both 154, and 160 are cut off a positive output pulse is produced on line 184. At the end of the coarse level at which 160 is cut off the "knockdown" of the "fine" staircase applies a positive potential to capacitor 168 on lead 182 and switches valve 160 on again to terminate the output pulse. The output pulse produced switches on r.f. oscillator 190 to ionize the gas in diode switches 192 (see Division H3), which connect the regenerate signal inputs 220, 222, to the capacitors 102,122 and produce also output pulses if capacitor 212 is previously charged through switch 216. Further switches may be connected to a second generator 224 to reset the circuit. Specification 825,646 is referred to.