Non-linear analog to digital converter

Abstract

First terminals are equally spaced on a substantially uniformly resistive thin film at or near a first side edge of the film at progressive positions downwardly from the top of the film. Near the bottom of the film, second terminals are preferably equally spaced progressively inwardly from the first side edge of the film. An energizing potential is applied to the film either at the corner defined by the top and the first side edge of the film or in a curved pattern of positions near such corner. A reference potential (e.g. ground) is applied to the film near the otherside of the film and near the bottom edge of the film. Voltages are thus produced at the successive ones of the first terminals with an exponential relationship with respect to such terminal positions and at the successive ones of the second terminals with a linear relationship with respect to such terminal positions. The disposition of the second terminals may be compensated for deviations in a logarithmic response in an output member (e.g. an electron gun in a cathode ray tube) receiving the voltages on such terminals. Cuts may be provided from the other side edge of the resistive surface in a horizontal direction partially toward the first side edge of the resistive surface to decrease the width of the resistive surface. Each of a plurality of comparators receives an input voltage first and second and the voltage at an individual one of the terminals. The comparators provide an output indicative of magnitude of the input voltage.