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Journal of the Society of Motion Picture Engineers ( Volume: 38, Issue: 3, March 1942)
[ACTIVE]

Stabilized Feedback Light-Valve

Metadata

Publisher
SMPTE
Doc Type
Journal Article
Article Type
research-article
Abstract
Feedback affords controlled and undistorted damping of light-valve resonance. All electromechanical devices can be regarded as feedback circuits if their motional impedance is interpreted as a feedback counter-emf. Auxiliary amplification of this counter-emf produces stabilized motional feedback. Depending on whether the amplifier counter-emf is proportional to amplitude, velocity, or acceleration, the feedback tends to flatten amplitude, velocity, or acceleration response characteristic. The light-valve is a mechanically resonant device operated on an amplitude basis but with a velocity counter-emf. Velocity feedback increases the effective damping of the light-valves; reactive components in the electrical driving impedance and in the feedback-gain tend to shift the resonance frequency. At 0.71 of critical damping the steady-state frequency characteristic is peakless and the valve follows transient impulses quickly with only 6 per cent overshooting. The maximum “bucking power” opposed to the valve motion by the feedback amplifier occurs at 0.58 of ribbon resonance and is 8 db less than the low-frequency power of the driving amplifier. An amplifier is described that has been designed in accordance with the theory for application of stabilized feedback to commercial light-valves.
Publication Date
1942-03-01
DOI
10.5594/J09917
Link
https://doi.org/10.5594/J09917
Author(s)
W. J. Albersheim, L. F. Brown
Source Data (JSON)

Full registry record with provenance metadata. Open directly: /api/doc/10.5594-J09917.json

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W. J. Albersheim and L. F. Brown; Stabilized Feedback Light-Valve, Journal of the Society of Motion Picture Engineers ( Volume: 38, Issue: 3, March 1942); SMPTE, 1942. Available at https://doi.org/10.5594/J09917
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W. J. Albersheim and L. F. Brown; Stabilized Feedback Light-Valve, Journal of the Society of Motion Picture Engineers ( Volume: 38, Issue: 3, March 1942); SMPTE, 1942. Available at https://doi.org/10.5594/J09917

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W. J. Albersheim and L. F. Brown; Stabilized Feedback Light-Valve, Journal of the Society of Motion Picture Engineers ( Volume: 38, Issue: 3, March 1942); SMPTE, 1942. Available at https://doi.org/10.5594/J09917
Snippet:
<span class="citation">W. J. Albersheim and L. F. Brown; <cite>Stabilized Feedback Light-Valve</cite>, Journal of the Society of Motion Picture Engineers ( Volume: 38, Issue: 3, March 1942); SMPTE, 1942. Available at <a href="https://doi.org/10.5594/J09917" target="_blank" rel="noopener">https://doi.org/10.5594/J09917</a></span>

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Preview:
W. J. Albersheim and L. F. Brown; Stabilized Feedback Light-Valve, Journal of the Society of Motion Picture Engineers ( Volume: 38, Issue: 3, March 1942); SMPTE, 1942
doi: 10.5594/J09917
url: https://doi.org/10.5594/J09917
Snippet:
<li>
W. J. Albersheim and L. F. Brown; <cite id="bib-10-5594-j09917">Stabilized Feedback Light-Valve</cite>, Journal of the Society of Motion Picture Engineers ( Volume: 38, Issue: 3, March 1942); SMPTE, 1942
<span class="doi">10.5594/J09917</span>
</li>