Abstract: An instant synchronous automatic gain control apparatus for a barcode reading device includes a sensor unit, a current amplification unit, a first stage amplification unit, a buffer stage amplification unit, a signal pickup amplification unit, a second stage amplification unit, a third stage amplification unit, a signal output amplification unit, a signal isolation match unit, and a signal rectification unit. When the barcode reading device receives a weak signal, the apparatus will process the signal and gain control synchronously and transmits desired digital signals to a microprocessor (CPU) or decoder circuit for processing.

Abstract: An instant synchronous automatic gain control apparatus for barcode reading device includes a sensor unit, a current amplification unit, a first stage amplification unit, a buffer stage amplification unit, a signal pickup amplification unit, a second stage amplification unit, a third stage amplification unit, a signal output amplification unit, a signal isolation match unit, and a signal rectification unit. When the barcode reading device receives a weak signal, the apparatus will process the signal and gain control synchronously and transmits desired digital signals to a microprocessor (CPU) or decoder circuit for process.

Abstract: The invention relates to a device for reading coded information, comprising illumination means, means for picking-up a luminous signal diffused by an illuminated support containing coded information, means for detecting the luminous signal intended to generate an electrical signal that is proportional to said luminous signal (for example, an electrical signal with an amplitude variable, along at least one reading direction, between at least one maximum value Vmax and at least one minimum value Vmin), and means for processing said electrical signal, intended to extract the information content from it. The device further comprises means for varying, preferably point by point, the amplitude pattern of said electrical signal along said at least one reading direction so as to generate an electrical signal having a predetermined amplitude pattern, for example, substantially constant.

Abstract: A gain control circuit for a telephone, the circuit comprising a signal strength calculator for calculating the strength of a signal; a gain controller adapted to modify the strength of the signal in accordance with a predetermined criterion based on the strength of the signal calculated by the signal strength calculator.

Abstract: The detecting method described is conceived for use in a bar code decoding system based on digital processing of signals. it functions to process in real time a signal from an A/D converter and determined the portions of this signal which contain a likely bar code and rejecting the portions that surely do not contain a code. Only the former are signaled to a subsequent decoding process. The method steps are essentially the following: determining local maxima and minima of the digitalized analog signal; determining valid transitions; calculating the side of constant brightness zones located between two successive valid transitions; determining likely codes; if appropriate, repositioning the code starting zone; and if appropriate, analyzing detected potential codes for congruence, and signaling the likely codes.

Abstract: An optional device for reading and decoding bars of different reflectivity arranged in accordance with a barcode and adjoining one another. The device includes an optical scanning device for scanning the bars by a light beam, a sensor for receiving the reflected light beam and converting the latter into an electrical sensor output signal, a transition detector for detecting the level transitions of the electrical sensor output signal and a decoding device which decodes the scanned barcode on the basis of the output signals from the transition detector. The sensor output signal is fed to an amplitude averaging device and/or contrast averaging device, the output of which is connected to a decision device which controls the decoding device in such a way that reading and decoding of the barcode is carried out several times if the output signal from the amplitude averaging device and/or contrast averaging device is below at least a predetermined threshold value.