Keysight N5224B, Руководство по обслуживанию

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Keysight N5224B/25B Service Guide 5-11
Theory of Operation
Synthesized Source Group Operation
The outputs at the front panel test ports are swept, stepped or CW signals.
Maximum leveled output powers are also listed in the “Data Sheet and
Technical Specifications documents.”
2 For a simple block diagram of the
Version 7 synthesizer source group, refer to Figure 5-7 on page 5-17 .
In this section the following are described:
— Basic Operation
— A4, A15, and A17 13.5 GHz Synthesizer Boards (S/N Prefixes
<
6021 Only)
— 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 (S/N prefixes
<
6021 Only) (including
rear-panel interconnects)
— A23 Test Set Motherboard (including rear-panel interconnects)
— A70 4-Port and A75 2-Port Low Frequency Extension (LFE) Board
(including rear-panel interconnects)
Basic Operation
This section contains the following:
— “Version 6 and Below Synthesizers Basic Operation”
— “Version 7 Direct Digital Synthesizer (DDS) Assembly – Basic Operation”
on page 5-16
Version 6 and Below Synthesizers Basic Operation
Table 5-6 on page 5-14 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).
1
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.
1. A26 splitter only applies to PNA models with serial number prefix
<
6021.