In telecommunication, reference noise is the magnitude of circuit noise chosen as a reference for measurement. Note: Many different levels with a number of different weightings are in current use, and care must be taken to ensure that the proper parameters are stated. See also: dBa, dBa(F1A), dBa(HA1), dBa0, dBm, dBm(psoph), dBm0, dBrn,dBrnC, dBrnC0, [[dBrn(f1-f2)]], dBrn(144-line), dBx. Source: From Federal Standard 1037C and from MIL-STD-188