Agilent Technologies HP 8719D Service Manual page 349

Receiver Theory
The receiver measures and processes the input signals into digital information
for display. Figure 12-7 is a simplified block diagram of the receiver functional
group. The Al2 reference assembly, which is part of the source group, is also
included in the illustration to show how the 2nd LO signal is derived.
Figure 12-7. Receiver Functional Group, Simplbd Block Diagram
Samplers and Second Converters
Each input signal goes to one of three identical pairs of sampler and second
converter assemblies (R, A, and B) that down-convert the signals to a llxed 4
Signal
The LO
by a step recovery diode in the A52 pulse generator. Refer to "Source Group
Theory" for details.
is a comb of harmonics of the synthesizer signal, produced