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.
REPRODUCTION IN THE THEATRE
385
PERMANENT MAGNET.
STYLUS
ARMATURE.
tage with corresponding variations is induced in the coil. This induced voltage is an electrical image of the sound record.
A section of this type of reproducer is shown in Fig. 2. This is a simple schematic diagram which will serve to illustrate the fundamental electric principle involved in the transformation of
the sound record into an electric image of the record. FILM REPRODUCER With the optical or film record the situation is somewhat different. In this case the pressure variations caused by the sound have been transformed into a photographic image on the edge of the film. In the variable density film record this image takes the form of alternate light and dark lines running across that portion of the film reserved for the sound track. The separation between these lines depends upon the frequency of the sound while the contrast between the light and dark parts represents the loudness or intensity. In the variable area method the sound record is made by varying the width of the dark portion of the sound track. While with this variable area method the unmodulated track consists of a dark and a light band each one-half the width of the sound track, in the variable density method unmodulated track appears a uniform gray over the entire width.
In transforming the film record into electric energy the essential elements required for this transformation consist of an exciting lamp, a lens system and a photoelectric cell.
Fig. 8 is a schematic diagram of the sound head, parts of which will be described later in detail. It is evident from the relative location of apparatus as shown in Fig. 3 that it is not feasible to print the film sound record directly beside the picture to which it applies. The sound track is printed approximately 15 inches in advance. This allows some slack between the sprocket which carries the picture with an intermittent motion
•SPEECH OUTPUT.
REPRODUCER.
FIGURE 2