Patent US 4,199,677

A bar code reader employs a microprocessor for decoding data contained in a bar code record and a logarithmic converter ahead of the microprocessor for providing to the microprocessor signals indicative of the logarithms of the widths of the scanned bars and spaces. The base of the logarithms used by the logarithmic converter is selected in a predetermined manner to maximize the resolution of the system for the particular microprocessor used, and to reduce the complexity of the system.