Agilent Technologies N5230A, Service Manual, Page: 123 / 262

Service Guide N5230-90014 5-3
PNA Series Microwave Network Analyzers Theory of Operation
N5230A Network Analyzer System Operation
Network Analyzer System Operation
The PNA-L network analyzer generates a phase-locked incident signal and an LO signal
from the internal synthesized source. By means of signal separation, the incident signal is
divided into a reference signal and a test signal.
The reference signal is applied to the receiver group, while the test signal is applied to the
device under test (DUT) and then to the receiver group. The LO signal is applied directly to
the receiver group where it is mixed with the test and reference signals to produce IF
signals for each of the four channels. These IF signals are downconverted and then
sampled and digitally processed.
Figure 5-1 is a simplified block diagram of the network
analyzer system.
Figure 5-1 System Simplified Block Diagram
Functional Groups of the Network Analyzer
The operation of the network analyzer can be separated into major functional groups. Each
group consists of assemblies that perform a distinct function in the instrument. Some of
the assemblies are related to more than one group, and all of the groups, to some extent,
are interrelated and affect each other's performance. The major functional groups are:
• Synthesized Source Group
• Signal Separation Group
• Receiver Group
• Digital Processor and Digital Control Group
• Power Supply Group