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.
260 IX. SOUND-RECORDING EQUIPMENT AND ARRANGEMENT
are coated to provide maximum transmission in the violet (400 m/z) end of the spectrum. The lens system is also corrected for the red end of the spectrum so that the machines may be used for exposing sound track on Kodachrome and other integral tri-packs such as Ansco Color. The same general optical design is used for the film phonograph and for the sound printer as these machines may also be called upon to run integral tri-pack films as well as black-and-white films.
Recording machines are focussed at 15,000 cps in production; every machine shipped has made a reasonably clear-cut record at this frequency. The galvanometer used in the machine resonates at 12,000 cps ; the resonance amplitude is about 7 decibels. A small dip occurs in the response-frequency characteristic at 4500 cps. This is corrected by a resistance-capacitance equalizer. With good commercial processing, a print on Eastman 5302 film is about 15 1/2 decibels down at 10,000 cps when made from a "flat" negative recorded upon Eastman 5372 film. This performance is now as good at 10,000 cps as was the performance of 1939 at 6000 cps. The recording machine can provide either negative sound track or direct positive sound track at will. Depressing and rotating a knob changes the type of recording from variablearea to variable-density by removing one of a crossed pair of cylindrical lenses from the optical train where they act as an objective.
A new film phonograph using as many parts as possible in common with the film-recording machine has a reproducing slit width of about 0.0003 in. The slit loss of this machine is quite small at 10,000 cps ; the photocell and its coupling circuit account for a considerable portion of the over-all loss. As the intermodulation distortion can be made quite low on the film, it has been practicable in a production machine used for test to equalize the associated preamplifier so that the over-all response of the film phonograph is "flat" to 10,000 cps. The over-all quality obtained with a print compares quite favorably with that obtained using a 35-mm Hollywood product in a well-maintained neighborhood entertainment theater. Widespread use of film of such quality is a possibility for the foreseeable future when projection of such films on good projectors under suitable acoustical environment will enable the 16-mm sound film to be an even bigger and better tool than it is today.
The Recording Amplifier Functional Components Although the physical forms and arrangements for recording amplifiers vary widely, modern equipment is characterized not so much by