Keysight x-series Instruction Manual

3 Short-Range Comms & IoT Mode
3.12 Monitor Spectrum Measurement
Mech Atten
Labeled Mech Atten in Dual-Attenuator models, and Atten in Single-Attenuator
models. In the Dual-Attenuator configuration, this control only affects the
mechanical attenuator.
Lets you modify the attenuation applied to the RF input signal path. This value is
normally auto-coupled to Ref Level, "Internal Preamp" on page 1657 Gain, any
External Gain that is entered, and Max Mixer Level (if available), as described in the
table below.
See "Attenuator Configurations and Auto/Man" on page 1641
Remote Command
[:SENSe]:POWer[:RF]:ATTenuation <rel_ampl>
[:SENSe]:POWer[:RF]:ATTenuation?
Example
:POW:ATT 20
Dual-Attenuator configuration: sets the mechanical attenuator to 20dB
Single-Attenuator mode: sets the main attenuation to 20dB (see below for definition of “main”
attenuation)
In either case, if the attenuator was in Auto, it is set to Manual
Dependencies Some measurements do not support Auto setting of Mech Atten. In these measurements, the
Auto/Man selection is not available, and the Auto/Man toggle function is not available
In Dual-Attenuator configurations, when the electronic attenuator is enabled, the mechanical
attenuator has no auto setting, and the Auto/Man toggle function is not available. The state of
Auto/Man is remembered and restored when the electronic attenuator is once again disabled. This is
described in more detail in "Elec Atten" on page 1641
See "Attenuator Configurations and Auto/Man" on page 1641 for more information on the Auto/Man
functionality
Couplings If the RF Input Port is the RF Input:
–
If the USB Preamp is connected to USB, use 0dB for Mech Atten
–
Otherwise compute the auto-selected value of Mech Atten based on Reference Level, Int Preamp,
External Gain, Ref Level Offset, Max Mixer Level, µW Path Control and IF Gain settings. Limit this
value to be no less than 6dB (total attenuation below 6dB can never be chosen by Auto)
–
In N9041B, if the RF Input Port is RF Input2, use the formula above and subtract the value of "Full
Range Atten" on page 1638 from the result to determine the Mech Atten. Limit the value so that it
is never lower than 0dB and so that total attenuation, including Full Range Atten, is never less
than 6dB (total attenuation, including Full Range Atten below 6dB, can never be chosen by Auto)
In External Mixing and BBIQ, where the attenuator is not in the signal path, the attenuator setting
changes as described above when Mech Atten is in Auto, but no changes are made to the actual
attenuator hardware setting until the input is changed back to the RF Input
For CXA-m with Option FSA (Fine-Step Attenuator or 2dB steps), the FSA-like behavior is only
available when the frequency setting is <=7.5GHz. So, when the frequency is changed from below
Short Range Comms & IoT Mode User's &Programmer's Reference 1639

Keysight x-series Specifications

General

Analysis Bandwidth	Up to 1 GHz (depending on model)
Real-Time Bandwidth	Up to 1 GHz (depending on model)
Form Factor	Benchtop
Connectivity	LAN, USB, GPIB
Resolution Bandwidth	1 Hz to 10 MHz (depending on model)