PICTURE SIGNAL RECEIVER FOR FACSIMILE AND THE LIKE

摘要

The invention involves the simplification of a receiver/reproducer for facsimiles of the type which applies a constant amplitude signal of variable duration to a thermal sensitive paper. Use is made of two analog memories for storing alternately successive one-line segments of the picture signal. During the write-in period for a one-line segment, the immediately preceding one-line segment is subjected to amplitude comparison for each picture element, in which the comparison reference voltage is changed corresponding to the shade value vs. time duration characteristics of the recording paper. Thus, the amplitude comparison translates the amplitude information of the memory readout into the width of the comparison output pulse for each picture element defined by the pitch of the analog memories. With the comparison reference voltage supplied in common to all the amplitude comparators equal in number to the number of picture elements in one scanning line, the parallel output pulses from the parallel amplitude comparators have various pulse widths representative respectively of the amplitudes of respective picture elements. Thus, the reproduction of a picture having a gradation of shade values is realized.