Radio age research, manufacturing, communications, broadcasting, television (1941)

below: this model of electronic reading aid converts letters into their spoken sounds. at right: earlier model of re.\dini; aid permits user to recognize letters by distinguishing sounds when scanned by electron beam in hand-held stylus. Electronic Reading Aids Latest Experimental Model Automatically Converts Letters into their Normal Sounds — May be Useful in Translating Coded Patterns. A LABORATORY model of an electronic device which con- verts reading matter into the sounds of individual letters has been devel- oped by the RCA Laboratories Divi- sion of the Radio Corporation of America. The development work was carried out by Dr. V. K. Zwory- kin, L. E. Flory "and W. S. Pike of the Laboratories staff. In operation, a line of type is scanned letter by letter with a scanning mechanism containing a miniature cathode-ray tube and an optical system. Each printed letter is scanned vertically with a pin- point of light at a rate of 500 cycles per second. The scanning, however, is not continuous but is carried out so that the scanning spot pauses momentarily at several points along its path thereby creating the effect of a series of scanned spots ar- ranged in a vertical line. To facili- tate the recognition of signals from the individual spots of light, the spots are not present continuously, but are made to appear one after the other in a time sequence. If the series of spots forming the vertical line is now moved manually along the lines of type, the light, normally reflected by the white paper, will be interrupted by the black portions of letters. These in- terruptions can then be transformed into electrical impulses by means of a phototube and amplifier. As a result of the high speed vertical scanning and the manual scanning along the lines of print, the signal output of the phototube amplifier will be in the nature of the scanning frequency, modulated by the interruptions of light. Five to eight channels or spots of light are present in each vertical sweep of the scanning beam and are separated by a timing circuit and counted by electronic means. The total number of pulses from all channels is unique for most letters of the alphabet. One of the ambiguities exists in the case of b and d, since the num- ber of counts derived from these two letters is the same. But closer examination of b and d will show a difference in the sequence in which the pulses in the various channels occur. In b, for instance, none of the scanning spots will be reflected at the start of the scan- ning because of the letter's vertical portion on the left. By contrast, the solid vertical portion of d is encountered by the scanning spots at the extreme right. The informa- tion thus collected by the .scanning process can be combined with the balance of the scanning informa- tion to differentiate between the two letters. The output from the selector cir- cuits is used to operate a magnetic reproducer arranged so that, as a letter is recognized, a single re- cording of that letter is reproduced through a loud speaker. The indi- vidual letter sounds are recorded on separate discs driven by friction from a continuously rotating shaft. The instrument is believed to have possibilities as a recognition device for the translation of coded patterns such as those which form the basis of teletyped messages. INDIA PURCHASES THREE SOUND FILM RECORDERS Three RCA sound film recording systems, purchased by the Indian Government for the production of educational motion pictures and newsreels are expected to play a large part in India's plans to ac- quaint the people with the duties of citizenship in the new free state, according to official reports received by Meade Brunet, RCA Vice Presi- dent and Managing Director, RCA International Division. Under the plans, films covering a wide range of progressive topics in social and economic fields will be produced in Bombay and distributed to all parts of the country by the Indian Minis- try of Information. [RADIO AGE 29]