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.
NHH isiffi^^^w^v:^
Fig. 6. RCA 4-track magnetic-head assembly.
heads are inspected for conformity to design specifications for azimuth, head position, inductance and uniformity of output.
The head assembly is mounted in the soundhead adjacent to the drum so that the film contacts the head immediately after leaving the drum. Angle of contact of film on head is approximately thirty degrees. This degree of contact assures minimum amplitude modulation and is beneficial in prolonging useful head life. The head location is at the portion of the film path where best film motion exists.
Flutter content is less than 0.15% rms when measured with a test film having a flutter content of less than
0.1% rms. Amplitude modulation is less than 1 db. Uniformity of output is within IJ db at 8000 cycles and 1 db at 1000 cycles.
Since the size and configuration of the top surface of various projectors currently in use vary, it was impractical to design the soundhead for universal mounting. Instead, the unit was designed for mounting on a projector having a flat top surface of adequate area, and adapters have been designed and will be available to permit mounting the soundhead on the various other projectors now in use.
This magnetic reproducer will permit the same projector soundhead now reproducing optical tracks to reproduce multichannel or stereophonic sound without the need of a separate interlocked magnetic dummy. By combining the ability to reproduce either photographic or magnetic soundtracks into one projector-reproducer assembly, considerable savings may be realized over the double-film systems. Also, no additional floor space is required in the theater projection rooms. Sound reproduction using the attachment is of excellent quality and is within Research Council recommendations for magnetictrack reproduction.
220
March 1954 Journal of the SMPTE Vol. 62