One thing to consider with any attenuator set up is leakage. If you wish to create a 1 microvolt signal from an RF source good for 0 dBm then you will need 120 dB of attenuation. This will require putting about 40 dB of attenuation into shielded boxes with non coax connections between them (hard connectors like barrels will work) and will require three isolated boxes. The control lines will have to be seriously bypassed. Getting to .1 microvolt will require another 20 dB for a total of 140 dB of attenuation. Maintaining this amount of attenuation is difficult and it is one of the things that separates a good lab signal generator from a bad one. If you can look inside an HP/Agilent signal generator at the attenuator some time. Amazing
Rick w6nzk
