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US2137157A
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Apparatus for reproducing sound
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US2065172A
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Photoelectric sound reproduction of phonograms
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US2043884A
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Photoelectric sound recording or reproducing apparatus
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DE652518C
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Machine for photoelectric sound recording and playback
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DE657535C
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Apparatus for optical sound recording and reproduction
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DE676000C
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Device for eliminating the composite sound recordings at the joint edge during the optical-electrical reproduction
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DE691114C
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Light tone recording in serrated script
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DE663561C
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Clamping device for sheet-shaped light sound carriers
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