HP 70427A User Manual page 237

Technical Data
HP 70428A Option 002 Specifications
1
All noise levels above -30 dBc/Hz are 3 dB below S φ (f) expressed in dB with
2
respect to 1 rad /Hz
2
Mixing an RF source with the microwave LO in the HP 70428A Option 002 may
result in some mixing spurious exceeding spurious specifications, see mixing
spurious table on page X.
9-36 HP 70427A/HP 70428A User's Guide