Keysight Technologies N5224A Service Manual page 128

Theory of Operation
Network Analyzer System Operation
Synthesized Source Group
The built-in synthesized source generates a swept, stepped, or continuous
wave (CW) signal in the frequency ranges as listed in the Data Sheet and
Technical Specifications documents, available online at:
http://literature.cdn.keysight.com/litweb/pdf/N5224-90001.pdf
http://literature.cdn.keysight.com/litweb/pdf/N5224-90002.pdf
source group provides five signals: an LO signal and four incident signals. The
LO signal and the four incident signals are offset in frequency by the receiver IF
of 7.438 MHz (at tuned frequencies below 53 MHz the IF and the offset is 0.826
MHz).
The LO signal is sent directly to the mixers in the receiver group. The incident
signals are routed to the front panel test ports and then to the device under
test (DUT) as the test signal. A portion of each incident signal is coupled off (in
the signal separation group) and sent to the mixers in the receiver group as
reference signals. These reference signals are compared (mixed) with the LO
signal in the receiver group to produce the 7.438 MHz (or 0.826 MHz at
frequencies below 53 MHz) IF signal.
The incident signal output power is leveled by an internal automatic leveling
control (ALC) circuit. The maximum output power level of the network analyzer
at the test ports is shown in the Data Sheet and Technical Specifications
documents (see hyperlinks above).
Refer to
Signal Separation Group
Each of the incident signals from the source group is separated into a reference
path and a test path. The reference signal is transmitted to the receiver group.
The test signal is transmitted through—and reflected from—the DUT and is then
transmitted to the receiver group.
The signal separation group includes:
— RF path switching to allow forward and reverse measurements
— external connections for the DUT (configurable test set)
— optional step attenuators in the source and receiver paths
— optional bias tees
Refer to
1. For frequency ranges and maximum output power levels, refer to the section "Test
Port Output" in the Data Sheet and Technical Specifications documents (see
hyperlinks above).
5-4
"Synthesized Source Group Operation" on page
"Signal Separation Group Operation" on page
1 .
5-6.
5-17.
Keysight N5224A/25A Service Guide
and
1
. The