what is the meaning for "mask"??

[goodzyz]

Power waveform mask for a normal burst, who can tell me the exact meaning for the word "mask" in the front sentence. :?

 

[JnglMassiv]

I believe mask in this context refers to the overall footprint or appearance of the waveform amplitude with respect to frequency. This would be what one sees on a spectrum analyzer. The mask might convey requirements regarding maximum power at the center frequency as well as signal bandwidth and power of lobes or sidebands other than the center frequency.