Flat weighting
Flat weighting: In a noise-measuring set, a noise weighting based on an amplitude-frequency characteristic that is flat over a frequency range that must be stated.
Note 1: Flat noise power is expressed in dBrn (f1 - f2) or in dBm (f1 - f2). Note 2: "3 kHz flat weighting" and "15 kHz flat weighting" are based on amplitude-frequency characteristics that are flat between 30 Hz and the frequency indicated.
References
This article incorporates public domain material from the General Services Administration document "Federal Standard 1037C" (in support of MIL-STD-188).