Agilent Technologies X Series Manual page 379

Low Noise Path Enable
You may choose Low Noise Path Enable, which gives a lower noise floor under some circumstances,
particularly when operating in the 21–26.5 GHz region. With the Low Noise Path enabled, the low
band/high band switch and microwave preamp are bypassed whenever all of the following are true:
• The analyzer is not in the Low Band, meaning:
• the start frequency is above 3.5 GHz and
• the stop frequency is above 3.6 GHz.
• the internal preamp is not installed or (if installed) is set to
Note that this means that, when any part of a sweep is done in Low Band, the Low Noise Path is not
used, whether or not the
turned on, the Low Noise Path is not used, whether or not the
user interface. The only time the Low Noise Path is used is when
the sweep is completely in High Band (> 3.6 GHz) and no preamp is in use.
See "More Information" on page
Key Path
Measurement
Example
Notes
Dependencies
Readback Text
Initial S/W Revision
More Information
The user should understand that the Low Noise Path, while giving improved DANL, has the
disadvantage of decreased TOI performance and decreased gain compression performance relative to the
standard path.
The user should also understand that the bypass switch is a mechanical switch and has finite life; so if the
is enabled, it is possible to cause frequent cycling of this switch by frequently changing
Low Noise Path
Low Noise Path Enable
379.
AMPTD Y Scale, µW Path Control
Swept SA
:POW:MW:PATH LNP
For measurements that use IQ acquisition, the low noise path is used when the
Center Frequency is in High Band (> 3.6 GHz) and no preamp is in use.
In other words, the rules above are modified to use only the center frequency
to qualify which path to switch in.
This is not the case for FFT's in the Swept SA measurement; they use the
same rules as swept measurements.
Key is blanked if current mode does not support it.
Key is grayed out if mode supports it but current measurement does not
support it.
Unless Option LNP is present and licensed, key is blank and if SCPI
command sent, error –241, "Hardware missing; Option not installed" is
generated.
Low Noise Path Enable
A.04.00
or
Off Low Band
is selected in the user interface. Also, if the preamp is
Low Noise Path Enable
Low Noise Path Enable
AMPTD Y Scale
is selected in the
is selected,
379