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PNA Series Microwave Network Analyzers
N5241A/42A
Synthesized Source Group Operation
The source group produces a stable output signal by phase locking a synthesized
voltage-controlled oscillator (VCO). Refer to
range of the source. The outputs at the front panel test ports are swept, stepped or CW
signals. Maximum leveled output powers are listed in
block diagram of the source group, refer to
In this section the following are described:
•
Basic Operation
•
A4, A13, and A11 13.5 GHz Synthesizer Boards
•
A5 and A8 26.5 GHz Source Boards
•
A21 Multiplier/Amplifier 26.5 Board (HMA26.5)
•
A10 Frequency Reference Board
•
A19 Test Set Motherboard
Basic Operation
Table 5-2 on page 5-9
A13, and A11), and the main source frequency (A5 and A8) 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
The A10 frequency reference board produces a constant phase locked reference signal of
50 MHz that is sent to the A4, A13, and A11 13.5 GHz synthesizer boards.
The A11 13.5 GHz synthesizer board produces an LO signal that is sent through the A21
multiplier/amplifier 26.5 to the A23 and A24 mixer bricks (via the A22 splitter). The
frequency is synthesized such that the mixing product of this LO signal with the test
signal output is a constant 7.606 MHz IF; except for frequencies below 53 MHz when the
IF is 2.535 MHz. This IF signal is sent to the A12 SPAM board for digital processing.
The A4 and A13 13.5 GHz synthesizer boards each produce an incident signal that is sent
to the front panel outputs. A portion of these signals are coupled off and sent to the A23
and A24 mixer bricks (A
A22 splitter to produce the 7.606 MHz (or 2.535 MHz) IF signal.
The A4, A13, and A11 13.5 GHz synthesizer boards each contain their own phase lock
circuitry. The A11 board is used to phase lock the LO signal while the A4 and A13 boards
are used to phase lock the test signal. This makes it possible for the LO signal to be tuned
to a different frequency than the test signal, which is necessary since the LO signal is
normally 7.606 MHz higher than the test signal. Since the A4, A13, and A11 13.5 GHz
synthesizer boards each receive their 50 MHz input reference signal from the exact same
source, frequency drift error is eliminated.
Service Guide N5242-90001
(including rear-panel interconnects)
(including rear-panel interconnects)
lists the L.O. harmonic number, the synthesizer frequencies (A4,
Chapter 4, "Troubleshooting."
D and R1
R4) where they are mixed with the LO signal from the
–
–
Synthesized Source Group Operation
Table 5-2 on page 5-9
Table 5-1 on page
Figure 5-3 on page
5-8.
Theory of Operation
for the full frequency
5-5. For a simple
5-7
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Table of Contents
Troubleshooting
