| 摘要 |
A selfcalibrated sensor module for inkjet printing devices includes a new circuitry and a new calibration method to provide the best output signal independently of optical component functionality variations and external light source influences.The circuitry for processing the photodetector output signal is designed to process that signal by a bank of amplifiers or by an amplifier of variable gain and includes an input for adding an offset to the signal.The calibration system, implemented in a processing unit, calibrates the sensor module, firstly finding the level of light that should be applied to the LEDs to maximize it so as to grant the best signal possible, in terms of the signal to noise ratio (SNR), Secondly, it determines which amplification factor will be used in order to ensure that the resulting sampled signal is not saturated. Thirdly, it determines the necessary offset to be added to the signal to center it in the dynamic margin of the ADCs.
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