**IEC 60263**-2020 Scales And Sizes For Plotting Frequency Characteristics And Polar Diagrams.

This document 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. 2 NormatIve references There are no normative references in this document. 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain termiriological databases for use in standardization at the following addresses: • ISO Online browsing platform: available at https://wwwiso.org/obp • IEC Electropedia: available at http://www.electropedia.org/ 3.1aspect ratio scale proportion between the y-axis and x-axis of a graph Note 1 to entry: For graphs with a logarithmic frequency x•axis. the aspect ratio is expressed as the y.axis factor per decade (in frequency), for example 25 dBldecade. or 1.25 decadesldecade. 3.2decade factor of 10 on a logarithmic scale Note 1 to entry: For example, 500 Hz ts 1 decade above 50 Hz; 0,01 % is 3 decades below 10 %. 4 Characteristics plotted versus a logarithmic frequency scale 4.1 Decibel vs. log frequency plots For graphs in which the y-axis depicts a level (in decibels) plotted versus logarithmic frequency on the x-axis, the aspect ratio shall be 10 dB/decade. 20 dB/decade. 25 dB/decade or 50 dB/decade. NOTE Direct comparison of hardcopy printouts to older analogue plots is facilitated by ensuring that 1 dB is equal to 1 mm, 2 mm, or 5 mm. as required. 4.2 Log quantities vs. log frequency plots For graphs in which the y-axis depicts an absolute quantity or a percentage on a logarithmic amplitude scale plotted versus logarithmic frequency on the x-axis, the aspect ratio shall be 0,5 decades/decade, 1 decade/decade, 1,25 decades/decade or 2,5 decades/decade. NOTE These aspect ratios correspond exactly to the level equivalents of 10 dBldecade, 20 dB/decade. 25 dBldecade and 50 dB/decade in 4.1, respectively. 5 Polar level diagrams 5.1 General Polar level diagrams shall depict level as increasing outward versus radius. The angle of incidence shall be depicted as Increasing moving counterclockwise relative to the reference direction. The angle assigned to the reference direction shall be 0°. Major angular divisions shall be plotted as radii at a minimum of 30° intervals and shall be labelled. 5.2 Polar plots of absolute level For a polar plot of absolute level referred to a reference quantity (e.g. dB re. 2OpPa), the level range of the graph shall be 60 dB or 30 dB to the origin. For polar plots of absolute level with a range of 60 dB to the origin, the maximum level shall be plotted less than 10 dB below the circle of maximum radius. Major level divisions shall be plotted as concentric circles with radii in multiples of 10 dB. Major divisions shall be labelled. Optional minor divisions are plotted as circles in 2 dB intervals without labels. For polar plots of absolute level with a range of 30 dB to the origin, the maximum level shall be plotted less than 5 dB below the circle of maximum radius. Major level divisions shall be plotted as circles with radii in multiples of 5 dB. Major divisions shall be labelled. Optional minor divisions are plotted as circles in 1 dB intervals without labels.IEC 60263 pdf download.