Keysight N9010B - Page 267

3 VMA Mode
3.1 Digital Demod Measurement
–
the stop frequency is above 3.6 GHz.
–
the internal preamp is not installed or if installed, is set to Off or Low Band
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 Full Bypass Enable is selected in the user
interface. Also, if the preamp is turned on, the Low Noise Path is not used, whether
or not the Full Bypass Enable is selected in the user interface. The only time the Low
Noise Path is used is when Full Bypass Enable is selected, the sweep is completely in
High Band (> 3.6GHz) and no preamp is in use.
CAUTION
When Full Bypass Enable is selected, and "Y Scale" on page 1760 is set to
0dB, there will be a direct AC connection between the input and the first
converter when the Low Noise Path switches in (when Start Freq >3.6GHz and
the Preamp is either not licensed, set to Low Band, or Off). This puts the first
converter at considerable risk to be damaged by high AC power. Consequently,
whenever Full Bypass Enable is selected, a warning message appears in the
status bar:
“Full Bypass Enabled, maximum safe input power reduced”
Microwave Preselector Bypass Backwards Compatibility
Example Bypass the microwave preselector:
:POW:MW:PRES OFF
Notes Included for Microwave Preselector Bypass backwards compatibility
The ON parameter sets the STD path (:POW:MW:PATH STD)
The OFF parameter sets path MPB (:POW:MW:PATH MPB)
Preset
ON
Backwards
Compatibility
SCPI
[:SENSe]:POWer[:RF]:MW:PRESelector[:STATe] ON | OFF | 0 | 1
[:SENSe]:POWer[:RF]:MW:PRESelector[:STATe]?
Frequency Extender Preselection Bypass
Only applies to the high frequency path of the Frequency Extender, and only if the
Frequency Extender allows it. For example, the V3050A high frequency path is 50 –
110GHz and does allow control of the preselector bypass.
When the Frequency Extender’s preselection is bypassed, flatness is improved, but
will be subject to spurs from out-of-band interfering signals. For bandwidths greater
than 2.5[GHz], it is recommended that the signal bypass the Frequency Extender
Preselector since the max bandwidth of the Preselector can be as narrow as 2.5
[GHz].
267 Vector Modulation Analyzer Mode User's &Programmer's Reference