Agilent Technologies EMC Series User Manual page 77

Selects 1 MHz resolution bandwidth (ResBW). FCC regulations specify
1 MHz BW Type
6 dB 1 MHz RBW for measurements above 1 GHz. CISPR regulations
Impulse 6 dB 3 dB
(1999) specify 1 MHz IMPULSE RBW. Spectrum analyzers use
3 dB RBW.
Key Access:
Chapter 2
,
BW/Avg More
Front-Panel Key Reference
BW/Avg
77