Keysight N5224B, Руководство по обслуживанию

Страница: 183 / 614

Keysight N5224B/25B Service Guide 5-21
Theory of Operation
Synthesized Source Group Operation
The DDS assembly’s carrier board’s also produces a 19.2 GHz signal that is
split and sent to each of the DDS Slugs to drive the LO, SRC1, SRC2, and SRC3
(SRC3 requires, Option XSB).
In bands 2 to 7, the DDS Slug’s output is used to produce the output
frequencies of 10 MHz to 6 GHz that is transmitted to the DDS assembly
multiplier section as listed in Table 5-2 on page 5-18 .
In bands 8–30, the DDS Slug’s signal is passed through a doubler circuit where
bands 8–10 and 12–17, and 20–29 are sent directly to the output of the DDS
assembly while bands 11,18–19, and 30 are passed through another doubler
circuit then to the output of the DDS assembly to produce the output
frequencies listed in Table 5-2 on page 5-18 .
Refer to Note on page 4-31 . The output of the A15 13.5 GHz DDS assembly
(the LO synthesizer section) is a frequency value higher than the output of the
source 1 and source 2 13.5 GHz synthesizer portions of the DDS assembly. This
is because the output of the A15 13.5 GHz synthesizer assembly is routed
through the A25 LO multiplier/amplifier 26.5 board to the A27 and A28 mixer
bricks where they are mixed with the test signals to produce a 7.606 MHz IF
signal for each of eight receivers (A–D and R1–R4). Refer to “A27 and A28
Mixer Bricks” on page 5-47 for a more complete description.
Rear-Panel Interconnects
A5 and A10 26.5 GHz Source Boards
The A10 26.5 GHz source board is included only on 4-port models.
Refer to
Table 5-6 and Figure 5-6 for band numbers and frequencies discussed
here.
In bands 2–9, the A5 and A10 26.5 GHz source boards input signals from the
A4 or A17 13.5 GHz synthesizer board are passed through to both outputs
(main and secondary) unchanged.
For bands 10–15 and 19–23, the input signals are passed directly to the
secondary output or amplified and filtered, then sent to the main output.
For bands 16–18 and 24–30, the input signals are doubled, filtered, and
amplified. The signals for these bands are then either passed directly to the
secondary output or passed through more amplification and filtering and sent
to the main output.
REF INPUT (s/n prefixes
≥
6021
only)
A BNC connector that allows an external frequency reference signal to be used to
phase lock the analyzer for increased frequency accuracy.
The analyzer automatically enables the external frequency reference feature when
a signal is connected to this input. When the signal is removed, the analyzer
automatically switches back to its internal frequency reference.
REF OUTPUT (s/n prefixes
≥
6021
only)
A BNC connector that allows a reference signal, produced by the A15 DD
synthesizer board, to be output for use in phase locking external test equipment.