Journal of the Society of Motion Picture Engineers (1930-1949)

Record Details:

Something wrong or inaccurate about this page? Let us Know!

Thanks for helping us continually improve the quality of the Lantern search engine for all of our users! We have millions of scanned pages, so user reports are incredibly helpful for us to identify places where we can improve and update the metadata.

Please describe the issue below, and click "Submit" to send your comments to our team! If you'd prefer, you can also send us an email to mhdl@commarts.wisc.edu with your comments.




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.

178 TEMPLIN August Fig. 18 shows the frequency-response characteristic for the highfrequency equalization . For 35-mm recording this consists of an equalizer having response complementary to the resonance characteristic of the light valve, thereby making the lightvalve modulation correspond to that of the signal over the entire useful frequency range. This characteristic introduces a loss of 9 decibels at the light-valve resonant frequency of 9000 cycles. For 16-mm recording this equalizer is switched to provide a low-pass filter cutting out slightly above 5000 20 too 5000 IOOOO 20000 200 500 1000 2000 FREQUENCY IN CYCLES PER SECOND Fig. 18 — Light-valve equalizer and low-pass filter characteristics. cycles in order to suppress those frequency components beyond the 16-mm useful range. OVER-ALL SYSTEM CHARACTERISTICS Typical over-all-electrical-response characteristics for recording on 35-mm film are shown in Fig. 19. For dialog recording the low frequencies are attenuated and the mid-range boosted to obain the most realistic dialog quality. The light-valve equalizer is used to complement the effect of light-valve resonance. For music the low-frequency and mid-frequency equalization are removed. The lightvalve equalizer is left in the circuit to provide an over-all system response (up to the film) which is flat over the useful frequency range, thereby obtaining the maximum fidelity for the recorded music. In Fig. 20 a typical over-all electrical response for 16-mm recording is shown. As previously described, for dialog recording the 1<>\\