| 摘要 |
PURPOSE:To easily compensate non-linear photoelectric conversion distortion and to obtain a digital signal having accurate intermediate tone, by setting an output voltage of a critical voltage set circuit so that the voltage can be of opposite characteristics as non-linear distortion of an analog picture information signal. CONSTITUTION:An optical signal l scanning a transmission original and incident to a photoelectric converter 12 is converted into an analog picture information signal (a) at the converter 12 and inputted to comparators 4, 5, and 6. These comparators compare critical voltages (b), (c) and (d) being outputs of critical voltage set circuits 1, 2 and 3 with the signal (a) are compared, and output signals (e), (f) and (g) of ''0'' and ''1'' level. The critical voltages (b), (c), and (d) are set to be provided with opposite characteristics to non-linear distortion of the analog signal (a). An output signal from each comparator is encoded at an encoder 7 based on a signal (h) and outputted as digital signals (i), (j) in 2-bit. |
