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

[ACTIVE]

Stabilized Feedback Light-Valve

Metadata

Publisher: SMPTE — White Plains, NY, USA
Doc Type: Journal Article
Content Type: Original Research
Abbreviated Title: J SMPE
Volume: 38, No. 3, pp. 240–255
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
ISSN: Print: 0097-5834
Link: https://doi.org/10.5594/J09917
Author(s): W. J. Albersheim
L. F. BrownElectrical Research Products Division of Western Electric Company, New York, N. Y., and Hollywood, Calif
Copyright: © 1942 Society of Motion Picture and Television Engineers, Inc.

Bibliographic Reference(s)

1 Black H. S. : “Wave Translation System” ; U. S. Patent 2,102,671. EXTERNAL
2 Maxfield J. P. Harrison H. C. : “Vibratory System” ; U. S. Patent 1,535,538. EXTERNAL
3 Albersheim W. J. Sette W. J. : “Recording System” ; U. S. Patent 2,157,880. EXTERNAL

Source Data (JSON)

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

Reference Tree

Explore all references and references to this document, as a navigable tree.

Open Reference Tree

Reference this Doc

Plain text (ISO 690 compliant)

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. Available at https://doi.org/10.5594/J09917

Snippet:

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

HTML (ISO 690 compliant)

Preview:

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>

SMPTE's HTML Pub

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>

Referenced By

Variable-Area Recording with the Light Valve [Active]