MT 25 - TC 29/MT 25

IEC 60263:2020 specifies standard aspect ratios for logarithmic or level characteristics expressed in decibels versus a logarithmic frequency axis and ranges for the radius of polar diagrams of level. Applications include hard copy printouts, electronic files (e.g., PDF files), scientific publications, screen displays in computer programs and apps, as well as graphs in standards.
Informative examples of graphs that conform to the requirements in this document are found in Annex A.
Although outside the scope of this document, graphs with a linear y-axis versus logarithmic frequency (e.g., phase, group delay, etc.) often accompany the standard aspect ratio graphs of level described in the normative part of this document. These are described in informative Annex B.
IEC 60263:2020 cancels and replaces the third edition published in 1982. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) the scope is expanded to include electronic files (e.g., PDF), scientific publications, graphs in other standards, and screen displays in programs and apps;
b) a Terms and Definitions clause has been added;
c) aspect ratios of 20 dB/decade, and 0,5, 1, 1,25, and 2,5 decades/decade have been added;
d) ranges of 60 dB or 30 dB are specified for polar plots of absolute level; a 30 dB range is specified for polar plots of relative level;
e) as most graphs are now computer generated, tolerances and sizes have been removed;
f) all informative figures have been updated with contemporary examples;
g) an informative annex with information about linear y-axis vs. logarithmic frequency has been added.