3 WLAN Mode
3.2 Channel Power Measurement
The LO phase noise is optimized for smaller offsets from the carrier, at the expense
of phase noise farther out.
The actual frequency offset within which noise is optimized is shown with in square
brackets, as this can vary depending on the hardware set in use. For example, in
some instruments this annotation appears as [offset <20 kHz]
With option EP0
:FREQ:SYNT 4
In instruments with Option EP0, the LO is configured for the best possible close-in
phase noise (offsets up to 600 kHz from the carrier), regardless of spurious products
that occur with some center frequencies. Because this is generally less desirable for
close-in measurements than the "Balanced" on page 284 setting, parameter 1
selects "Balanced" on page 284 in EP0 instruments, in the interests of optimizing
code compatibility across the family. Parameter 4 selects "Best Close-in" on page
283, which is usually not as good a choice as "Balanced" on page 284.
Balanced
:FREQ:SYNT 1
In instruments with EP0, the LO is configured for the best possible phase noise at
offsets up to 600 kHz from the carrier whenever there are no significant spurs within
the span observed with an on-screen carrier. When there will be such a spur, the LO
is reconfigured in a way that allows the phase noise to increase by 7 dB mostly
within ±1 octave around 400 kHz offset. The spurs will always be below −70 dBc.
Best Spurs
:FREQ:SYNT 5
In instruments with EP0, the LO is configured for better phase noise than the "Best
Wide-offset" on page 284 case close to the carrier, but the configuration has 11 dB
worse phase noise than the "Best Close-in" on page 283 case mostly within ±1
octave around 300 kHz offset. Spurs are even lower than in the "Balanced" on page
284 case at better than −90 dBc, whether or not the carrier is on-screen.
This setting is never selected when Phase Noise Optimization is in Auto, you must
select it manually.
Best Wide-offset
:FREQ:SYNT 2
The LO phase noise is optimized for wider offsets from the carrier. Optimization is
especially improved for offsets from 70 kHz to 300 kHz. Closer offsets are
compromised and the throughput of measurements (especially remote
measurements where the center frequency is changing rapidly), is reduced.
WLAN Mode User's &Programmer's Reference 284
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