104 Chapter 4
Troubleshooting the RF Section (E4446A, E4447A, E4448A)
RF Section Description (E4446A, E4447A, E4448A)
A20 Lowband
The Lowband assembly is the front end converter for frequencies below
3 GHz and the 2
nd
converter for input frequencies 26.8 GHz to 50 GHz.
The Lowband assembly encompasses both the first and second mixers,
the 2
nd
LO amplifiers, LO Nulling and filtering.
Figure 4-7 Lowband Assembly Block Diagram
Mixing equation: F
LO
= F
RF
+ F
IF
F
IF
= 3.9214 GHz