Analog to digital converter

Claim 1

DATA PROCESSING APPARATUS FOR CONVERTING AN INPUT VOLTAGE TO A CORRESPONDING DIGITAL REPRESENTATION BY MEANS OF A SUCCESSION OF PARALLEL COMPARISONS IN WHICH SAID INPUT VOLTAGE IS SIMULTANEOUSLY COMPARED WITH AN ORDERED SERIES OF REFERENCE VOLTAGES, SAID APPARATUS COMPRISING, IN COMBINATION, (A) A PLURALITY OF COMPARATORS, EACH COMPARATOR BEING CONNECTED TO COMPARE SAID INPUT VOLTAGE WITH A DIFFERENT REFERENCE VOLTAGE IN AN ORDERED SERIES THEREOF, (B) PROGRAM MEANS DEVELOPING CONTROL SIGNALS FOR INITIATING EACH COMPARISON BETWEEN SAID INPUT VOLTAGE AND A SERIES OF SAID REFERENCE VOLTAGES, (C) CODING MEANS CONNECTED WITH SAID COMPARATORS AND DEVELOPING, FOR EACH COMPARISON, A DIGITAL SIGNAL CORRESPONDING TO THE NUMBER OF REFERENCE VOLTAGES THAT ARE SMALLER THAN SAID INPUT VOLTAGE, (D) VOLTAGE PRODUCING MEANS (1) CONNECTED TO RECEIVE SAID CONTROL SIGNALS AND SAID DIGITAL SIGNALS DETERMINED IN PRECEDING COMPARISONS, AND (2) DEVELOPING IN RESPOND THERETO A NEW SERIES OF REFERENCE VOLTAGES FOR THE NEXT COMPARISON, (3) SAID VOLTAGE PRODUCING MEANS (A) DEVELOPING EACH SERIES OF REFERENCE VOLTAGES WITH AN INCREMENT BETWEEN SUCCESSIVE REFERENCE VOLTAGES NO GREATER THAN THE LEAST SIGNIFICANT DIGIT OF THE DIGITAL SIGNAL TO BE DEVELOPED WITH THE NEXT COMPARISON, (B) DEVELOPING, FOR THE INITIAL COMPARISON, THE SMALLEST REFERENCE VOLTAGE EQUAL TO THE SMALLEST INPUT VOLTAGE TO BE CONVERTED TO DIGITAL NOTATION PLUS 1.5 INCREMENTS, AND (C) DEVELOPING THE SMALLEST REFERENCE VOLTAGE FOR THE NEXT, SECOND, COMPARISON WITH A VALUE LESS THAN THE LARGEST REFERENCE VOLTAGE THAT SAID ANALOG VOLTAGE EXCEEDED IN SAID FIRST COMPARISON BY A VOLTAGE OF (I) ONE-HALF THE INCREMENT IN THE JUST COMPARISON (II) MINUS ONE AND ONE-HALF TIMES THE INCREMENT FOR THE NEXT COMPARISON, (III) WHEREBY THE MOST SIGNIFICANT DIGIT IN SAID DIGITAL SIGNAL FROM SAID CODING MEANS AS A RESULT OF SAID SECOND COMPARISON HAS THE SAME WEIGHT AS THE LEAST SIGNIFICANT DIGIT DEVELOPED IN SAID FIRST COMPARISON, AND (E) OUTPUT MEANS (1) CONNECTED WITH SAID CODING MEANS TO RECEIVE SAID DIGITAL SIGNALS DEVELOPED WITH SAID COMPARISONS, AND (2) DEVELOPING SAID DIGITAL REPRESENTATION BY SUMMING SAID DIGITAL SIGNALS DETERMINED IN SAID FIRST AND SECOND COMPARISONS, THEREBY CORRECTING ERRORS IN THE LEAST SIGNIFICANT DIGIT OF THE DIGITAL SIGNALS DETERMINED IN SAID FIRST COMPARISON.