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.
314
NEW MOTION PICTURE APPARATUS [J. S. M. P. E.
spools for the coils. This, plus the fact that the shutter resonates at a frequency well above the highest that can appear in the output current of the control amplifier, prevents "bouncing" or overshooting of the masks.
One matter to which particular attention has been paid in the design of recording equipment is that of phasing for speech. It has been well established that the majority of speech waves and many sounds from musical instruments are not symmetrical, having lesser amplitudes during the half-waves corresponding to
rarefaction of the air. This is because of the construction of the human voice mechanism. The lack of symmetry is plainly revealed in a variable-width soundtrack. If proper care is not exercised in phasing the recording channel from microphone to galvanometer, including
(•) No modulation Shutter cloied
Lamp
Modulation Shutter opening 75>
(e) Modulation 100* Shutter open
FIG. 4. Movements of the shutter masks as seen on monitor card.
Aperture Imaging
Lens
FIG. 5. Diagram of the shutter mechanism.
the noise-reduction amplifier, considerable interference can occur between the speech wave and the masking action. The requirements vary slightly depending upon the type of track being made. For standard recording, the longer peaks of a non-symmetrical wave should extend away from the noise-reduction or shuttered portion of the sound-track. This applies also to biased galvanometer recording. The noise-reduction amplifier is then phased to rectify the half of the wave containing the smaller amplitudes.
How this appears in the new shutter type of track is shown in Fig. 7. At the left is an example of wrongly phased speech. The correct phasing is at the right. It will be noticed that in the latter track the large peaks project toward the cen