Optical multiplexing

Claim 1

A DEVICE FOR READING A PRINTED PAGE, SAID PAGE BEING DIVIDED INTO LINES, SAID LINES BEING DIVIDED INTO CHARACTER CELLS SELECTED CHARACTER CELLS HAVING CHARACTERS PRINTED THEREIN; A SHUTTER, THE FREQUENCY OF WHICH VARIES AS A FUNCTION OF THE DISTANCE ALONG EACH LINE, WHEREBY A PARTICULAR BAND OF FREQUENCIES IS ASSIGNED TO EACH CHARACTER CELL; A PHOTORECEPTOR FOR GENERATING AN ELECTRICAL SIGNAL IN RESPONSE TO THE LIGHT INCIDENT THEREON; A LIGHT SOURCE FOR GENERATING LIGHT; AN OPTICAL SYSTEM FOR MODULATING SAID LIGHT BY BOTH SAID CHARACTERS AND SAID SHUTTER AND FOR DIRECTING THE MODULATED LIGHT TO SAID PHOTORECEPTORS; A PLURALITY OF BANDPASS FILTERS ONE FOR EACH CHARACTER CELL, EACH FILTER HAVING A PASSBAND CORRESPONDING TO THE FREQUENCIES ASSIGNED TO THE ASSOCIATED CHARACTER CELL; MEANS CONNECTING THE OUTPUT OF SAID PHOTORECEPTOR TO THE INPUT OF SAID BANDPASS FILTERS; MEANS FOR GENERATING A PLURALITY OF REFERENCE SIGNALS, EACH SIGNAL REPRESENTATIVE OF A DIFFERENT CHARACTER; AND MEANS FOR CORRELATING THE OUTPUT OF EACH FILTER TO EACH REFERENCE SIGNAL, WHEREBY THE CHARACTERS ON SAID LINES CAN BE IDENTIFIED.