Abstract
IN an article with this title (Bell. Lab. Rec., 21, No. 3 ; November 1942) O. D. Engstrom points out that the transmission tolerances of telephone circuits have become more severe, requiring a corresponding improvement in measuring technique and equipment. When a telephone circuit had only a few amplifiers or other circuit units, each could be permitted a larger share of the total permissible distortion, and errors in measurement of 0.25 db. meant very little. With the present transmission systems requiring many more circuit units than the earlier systems, this situation has changed. More accurate and faster operating testing equipment has been required, and a recording transmission-measuring set was developed that covers the voice-frequency spectrum in a few minutes. As originally used, the chart of this recorder could be read to about 0.2 db., but for many present-day measurements this is not adequate, and a new 'spread-scale' recorder has been developed that can be read to 0.02 db.
Article PDF
Rights and permissions
About this article
Cite this article
A SPREAD-SCALE RECORDER. Nature 151, 257–258 (1943). https://doi.org/10.1038/151257b0
Issue Date:
DOI: https://doi.org/10.1038/151257b0