Synthesized Source Group Operation; Basic Operation - Keysight N5224A Service Manual

PNA Series Microwave Network Analyzers
N5224A and N5225A

Synthesized Source Group Operation

The source group produces a stable output signal by phase locking a synthesized voltage-controlled
oscillator (VCO). For the full frequency range of the source, refer to 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
are swept, stepped or CW signals. Maximum leveled output powers are also listed in the Data Sheet and
Technical Specifications documents.
page 5-9.
In this section the following are described:
•

Basic Operation

• A4, A15, and A17 13.5 GHz Synthesizer Boards
• A5 and A10 26.5 GHz Source Boards
• A7, A8, A12, and A13 50 GHz Doubler Boards
• A25 Multiplier/Amplifier 26.5 Board (HMA26.5)
• A14 Frequency Reference Board
• A23 Test Set Motherboard
Basic Operation
Table 5-1 on page 5-10 lists the L.O. harmonic number, the synthesizer frequencies (A4, A15, and A17), the
main source frequency (A5 and A10), and the doubler frequencies (A7, A8, A12, and A13) within the analyzer
for each band. This table is referred to throughout this chapter and also appears on the overall block diagram
at the end of Chapter 4, "Troubleshooting."
The A14 frequency reference board produces a constant phase locked reference signal of 50 MHz that is
sent to the A4, A15, and A17 13.5 GHz synthesizer boards.
The A15 13.5 GHz synthesizer board produces an LO signal that is sent through the A25 LO
multiplier/amplifier 26.5 board to the A27 and A28 mixer bricks (via the A26 splitter). The frequency is
synthesized such that the mixing product of this LO signal with the test signal output is a constant 7.438
MHz IF; except for frequencies below 53 MHz when the IF is 0.826 MHz. This IF signal is sent to the A16
SPAM board for digital processing.
The A4 13.5 GHz synthesizer board produces an incident signal that is sent through the A5 26.5 GHz source
board and then through the A7 and A8 doubler boards to the front panel outputs. Likewise, the A17 13.5 GHz
synthesizer board produces an incident signal that is sent through the A10 26.5 GHz source board and then
through the A12 and A13 doubler boards to the front panel outputs. Portions of these signals are coupled off
and sent to the A27 and A28 mixer bricks (A
A26 splitter to produce the 7.438 MHz (or 0.826 MHz) IF signal.
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).
Service Guide N5225-90001
1
For a simple block diagram of the source group, refer to
(including rear-panel interconnects)
(including rear-panel interconnects)
D and R1 R4) where they are mixed with the LO signal from the
– –
Synthesized Source Group Operation
and
1
The outputs at the front panel test ports
Theory of Operation
Figure 5-3 on
5-7