ISSN:
1573-1987
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Summary A device is described, which can be used for amplifying and measuring the a.c. output of slow responding detectors (e.g. bolometers), receiving signals of constant but low frequency (∼1 Hz). This device, based on frequency conversion, which in principle is insensitive to drift-effects, consists of a primary galvanometer, a rotating disk, chopping the lightbeam reflected by the moving mirror of this galvanometer, and a phototube which receives the chopped lightbeam and which is coupled to an a.c. amplifier with an a.c. galvanometer as indicating instrument. The sensitivity of the instrument described, which had a response frequency of 1 2/3 Hz, proved to be limited by the Johnson noise of the input circuit only; drift effects proved to be greatly reduced.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02316507
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