# 13.4.2 Spectrum emission mask elements To create or modify a library element containing parameters of a particular spectrum mask, select the **Spectrum emission masks** command from the **Library pull-down menu** or directly with **CTRL+SHIFT+S**. A list of existing pre-defined spectrum emission mask will be selectable as shown in the figure below. This is an example of a LTE UE (Table 6.6.3.1-2 of 3GPP TS 36.101) where the limit for the spurious emission domain (outside ± 12.5 MHz) applies to frequencies above 1000 MHz: ![image.png](https://wiki.cept.org/uploads/images/gallery/2026-06/scaled-1680-/iYSbuIc3AJjxA3E7-image.png)
![](blob:https://ecowiki.atlassian.net/536d96e9-1d49-41d5-9711-0cdcdfdbfc9f#media-blob-url=true&id=c99b2997-23f0-4500-b32a-b5e614c67eb6&collection=contentId-493102&contextId=493102&width=945&height=588&alt=&clientId=113268fe-fe5b-4bc3-8ff3-07965dbf1d18)**Figure 284: Spectrum emission mask library elements**
When adding a new spectrum emission mask, enter the name (unique identifier) and description of its technical parameters. **Note 1:** It is possible to quickly scroll up and down and see the differences in the masks. **Note 2:** It is possible to create a mask from the workspace and export it to your library environment ![image.png](https://wiki.cept.org/uploads/images/gallery/2026-06/scaled-1680-/3dRCl5yzSfJcloZB-image.png)
![](blob:https://ecowiki.atlassian.net/23c64bfd-f0ce-442e-b46a-af312b565130#media-blob-url=true&id=70d48900-2a60-474c-b40f-7220c8978624&collection=contentId-493102&contextId=493102&width=465&height=108&alt=&clientId=113268fe-fe5b-4bc3-8ff3-07965dbf1d18)**Figure 285: Example on how to import/export to/from the workspace/library for the spectrum emission mask**