Block Edge Mask

A block edge mask is a transmitter spectrum mask that applies at the edge of a contiguous licensed block of spectrum and is designed to offer sufficient protection from interference to any anticipated receiving system in an adjacent frequency block.

The emissions of all transmitters operating within a licensed block must comply with this block edge mask, regardless of the bandwidth of such transmitters.

On one side of this frequency boundary is the in-block power limit and on the other side is the out-of-block spectrum mask. The out-of-block component of the BEM itself consists of a baseline level and, where applicable, intermediate levels which describe the transition from the in-block level to the baseline out-of-block level as a function of frequency. This is illustrated in the figure below.

Example of a block edge mask
Example of a block edge mask

A block edge mask doesn't define the means by which the radio transmitter meets the BEM. Usually, a spectrum emission mask (SEM) is defined by standardization organizations.

See also