We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
522 BROWDER November
film side of the above lens system. The aperture enclosed by the horizontal slit edges is imaged on the film by a cylindrical lens system whose axis is parallel to that of the horizontal slit. This lens system is located adjacent to the film so that the height of the recording image is greatly reduced from the actual spacing of the horizontal slit.
The two optical systems involved, that for defining the amplitude co-ordinate of the recording image and that for defining the recording image height are completely independent, since the cylinder lens does not participate in the magnification of the vertical ribbon edges and the slit defining the image height is located on the image side of the lens system employed in projecting the ribbon edges. This optical system permits the recording of a considerable variety of variable-area sound tracks, the electrical connections and the arrangement of ribbons to secure the various types of sound tracks being described in another paper.2
Two of the variations have been developed for use with this film recorder. The first of these employs three ribbons with speech current applied to the central one of the three and noise-reduction current applied to the outer two ribbons. Such a valve when used with this recorder will lay down a double-width push-pull, variablearea sound track. The other light valve employs but two ribbons with speech current impressed upon one and noise-reduction current on the other. An image-doubling device incorporated within the magnifying objective lens forms two images of the aperture defined by the light-valve ribbons. These images are formed side by side giving a sound track consisting of two, inphase unilateral, variable-area sound tracks with a total width at full modulation of 76 mils. This track will be referred to as a "dulateral" type of variable-area track. -Such a sound track has been shown to be adequately free of the type of distortion introduced by scanning with a reproducing optical system improperly adjusted for azimuth.2
GENERAL DESIGN OF THE VARIABLE-AREA LIGHT VALVE
The ribbons used in the variable-area light valves are sheared from 0.0005-inch thick duraluminum sheets. They are suspended between pairs of clamp carriages which are mounted so as to insulate each ribbon electrically from the case of the valve and from the other ribbons. These carriages provide a means for achieving an accurately coplanar setting of the several light-valve ribbons so that they will all be in sharp focus at the film, and also allow of adjustment during