3 Short-Range Comms & IoT Mode
3.7 ACP Measurement
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.
The actual frequency offset beyond 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 >30 kHz]
In instruments with Option 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.
Fast Tuning
:FREQ:SYNT 3
In this mode, the LO behavior compromises phase noise at many offsets from the
carrier in order to allow rapid measurement throughput when changing the center
frequency or span. The term "Fast Tuning" on page 962 refers to the time it takes to
move the local oscillator to the start frequency and begin a sweep; this setting does
not impact the actual sweep time in any way.
In instruments with EP1, the LO behavior compromises phase noise at offsets below
4 MHz in order to improve measurement throughput. The throughput is especially
affected when moving the LO more than 2.5 MHz and up to 10 MHz from the stop
frequency to the next start frequency.
In instruments with Option EP0, this is the same configuration as "Best Spurs" on
page 961. It is available with the "Fast Tuning" on page 962 label for convenience,
and to make the user interface more consistent with other X-Series instrument
family members.
(In models whose hardware does not provide for a "Fast Tuning" on page 962 option,
the settings for "Best Close-in" on page 961 are used if "Fast Tuning" on page 962 is
selected. This gives the fastest possible tuning for that hardware set.)
Auto
:FREQ:SYNT:AUTO ON
Selects the LO (local oscillator) phase noise behavior to optimize dynamic range and
speed for various instrument operating conditions. The selection rules are as
follows.
962 Short Range Comms & IoT Mode User's &Programmer's Reference
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