Keysight Technologies N5247B, Руководство по обслуживанию

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5-28 Keysight N5247B Service Guide
Theory of Operation
Synthesized Source Group Operation
5-
For bands 39–48, the input signals of all four doubler boards are doubled,
amplified and filtered, then sent to the doubler board output P2, creating the
full synthesized source output frequency range of 20 GHz to 35 GHz.
The output frequencies for each band are listed in
Table 5-7 .
The A7 40 GHz doubler board provides an EXT TSET DRIVE RF OUT signal to
the rear panel. This signal is output in bands 20–31 at a frequency range of
3.2–19 GHz for use with an external test set. This output is terminated with a
50-ohm load on the A8, A12, and A13 doubler boards.
The companion signal, EXT TEST SET DRIVE LO, is output from the A27 mixer
brick. Refer to “A27 and A28 Mixer Bricks” on page 5-53 .
A60, A61, A62, and A63 70 GHz Doubler Boards
The 70 GHz doubler boards create the full output frequency range of 10 MHz
to 70 GHz by combining two input signals from the 40 GHz doubler boards.
The first input signals are from the 40 GHz doubler P2 output (bands 39 - 48),
where the signals are filtered, doubled, amplified, and sent to the combiner.
The second input signals are from the 40 GHz doubler P6 output (bands 2 -
38), where the signals are passed through the 70 GHz doubler and sent to the
combiner. The forward combiner then combines both signals to create a full
range of 10 MHz to 70 GHz output.
A25 Multiplier/Amplifier 26.5 Board (HMA26.5)
In bands 2–28 and 36–39, the synthesized LO input is filtered, amplified, and
passed through to the A26 splitter
1
(4-port only). In bands 29–35 and 40–44,
the input is amplified, doubled, and filtered, then sent to the output.
Together, these signal paths create the full output frequency range of 12.5
MHz to 26.508 GHz that is sent to the A26 splitter (
<
6021 S/N prefixes, 4-port)
or internal splitter (
≥
6021
,
4-port only) where the signal is divided and sent to
the A27 and A28 (4-port only) mixer bricks as the LO signal.
A14 Frequency Reference Board (S/N prefixes
<
6021 Only)
This assembly provides stable reference frequencies to the rest of the
instrument. A high stability 10 MHz oven-controlled crystal oscillator (OCXO)
normally provides the frequency standard. However, if a 10 MHz external
reference signal is detected at the 10 MHz EXT REF IN port on the rear panel, it
is used as the frequency reference instead.
The 10 MHz reference signal is used to phase lock a 100 MHz VCO. The output
of this VCO is then divided by ten to produce the 10 MHz EXT REF OUT rear
panel signal and also a 10 MHz reference signal for the A16 signal processing
1. A26 splitter only applies to PNAs with serial number prefix
<
6021.