854
AMPTD Y Scale
Attenuator Configurations and Auto/Man
As described in the Attenuation key description, there are two distinct attenuator configurations available
in the X-Series, the single attenuator and dual attenuator configurations. In dual attenuator
configurations, we have the mechanical attenuation and the electronic attenuation, and the current total
attenuation is the sum of the electronic + mechanical attenuation. In single attenuator configurations, we
refer to the attenuation set using the (Mech) Atten key (or POW:ATT SCPI) as the “main” attenuation;
and the attenuation that is set by the SCPI command POW:EATT as the “soft” attenuation (the
POW:EATT command is honored even in the single attenuator configuration, for compatibility
purposes). Then the current total attenuation is the sum of the main + soft attenuation. See the Elec
Atten key description for more on “soft” attenuation.
In the dual attenuator configuration, when the electronic attenuator is enabled, there is no Auto/Man
functionality for the mechanical attenuator, and the third line of the key label (the Auto/Man line)
disappears:
Enable Elec Atten
Enables the Electronic Attenuator.
The electronic attenuator offers finer steps than the mechanical attenuator, has no acoustical noise, is
Min: 0 dB
The attenuation set by this key cannot be decreased below 6 dB with the knob
or step keys. To get to a value below 6 dB it has to be directly entered from the
keypad or via SCPI. This protects from adjusting the attenuation to a
dangerously small value which can put the instrument at risk of damage to
input circuitry. However, if the current mechanical attenuation is below 6 dB it
can be increased with the knob and step keys, but not decreased.
Max: CXA N9000A–503/507: 50 dB
CXA N9000A–513/526: 70dB
EXA: 60 dB
MXA and PXA: 70 dB
EXT: 70 dB
In the single attenuator configuration, the total of ATT and EATT cannot
exceed 50 dB, so if the EATT is set to 24 dB first, the main attenuation cannot
be greater than 26 dB and will be reduced accordingly; if the main attenuator
is set to 40 dB first, EATT cannot be greater than 10 dB.
Initial S/W Revision: Prior to A.02.00
Modified at S/W Revision: A.03.00
Mech Atten
0 dB
Mech Atten when elec
atten enabled
Mech Atten
0 dB
Auto Man
Mech Atten when elec
atten disabled vsd05