Abstract: An automatic electronically triggered scanner includes photo sensing apparatus for reading bar code data and for decoding the bar code data and then ascertaining whether the bar code data is valid. Following the reading and decoding of a valid bar code, the further decoding of bar code data by the scanner is inhibited until a predetermined condition is met to ensure that the bar code just read (which provided valid data) is not re-read. For the predetermined condition to be met the scanner must sense the absence of potentially valid bar code data for a preset interval following the decoding of each set of valid data. Subseqent to the preset interval during which only invalid data is present the scanner is placed in a condition to process valid data.

Abstract: There is disclosed a high-speed decoding apparatus for use in a flash-type analog-to-digital converter. The apparatus disclosed employs an OR gate which follows an AND gate which AND gate is conventionally employed in a comparator associated with such a converter. The OR gate functions to block any dynamic movement of the unknown input voltage from being transferred to the decode lines of the analog-to-digital converter. To further gain speed, autozeroed inverters are coupled to the output of the OR gate to further assure that the decoder lines are rapidly driven to therefore gain an extra advantage in high-speed operation of the converter employing the apparatus as described.

Abstract: A dual-slope analog-to-digital converter includes an integrator whose output may be driven from an initial zero voltage level to a value outside the linear region of the integrator in response to an input signal V.sub.X of unknown amplitude applied for a fixed integrating period T.sub.S. The output of the integrator is sensed and whenever the output voltage exceeds a preset limit a reference potential is applied to the integrator input, while the input signal is applied, to reduce its output below the preset limit. The time intervals the reference potential is applied during the period T.sub.S are measured and stored. Following the period T.sub.S the reference potential is applied until the integrator output is returned to the initial threshold level. The total time the reference potential is applied during the sampling period and after T.sub.S is accumulated enabling the determination of the value of V.sub.X.