Keysight Technologies N5247B, Service Manual

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Keysight N5247B Service Guide 5-45
Theory of Operation
Synthesized Source Group Operation
Version 7 synthesizers: Below 100MHz, the LFE option is enabled in the
firmware. With the direct digital synthesizer (DDS) assembly, a new LFE band
break is introduced at 4 MHz. This 4 MHz band break, corresponds to a switch
that directs the DDS output either through a balun (above 4 MHz) or
bypasses the balun (below 4 MHz). See also, “Version 6 synthesizers and
below” on page 5-44 .
The Figure 5-14 on page 5-45 shows an example of current frequency bands
in a PNA. In an N5247B PNA, the IF frequency will change around 53 MHz.
Figure 5-14 on page 5-45 shows the new structure of the frequency bands
with the LFE option. The two receiver modes, mixer and direct conversion, are
used in different frequency bands.
Figure 5-14 Frequency Bands Without LFE – Version 6 and Below Synthesizers (
<
6021)
Figure 5-15 Frequency Bands with LFE – Version 6 and Below Synthesizers (
<
6021)