Agilent Technologies X Series Manual page 354

AMPTD Y Scale
(Mech) Atten
This key is labeled
Mech Atten
dual attenuator configuration, this key only affects the mechanical attenuator.
This key lets you modify the attenuation applied to the RF input signal path. This value is normally auto
coupled to the Ref Level, the Internal Preamp Gain, any External Gain that is entered, and the Max
Mixer Level, as described in the table below.
See "Attenuator Configurations and Auto/Man" on page 355
Key Path
Remote Command
Example
Dependencies
Couplings
354
in dual attenuator models and
AMPTD Y Scale, Attenuation
[:SENSe]:POWer[:RF]:ATTenuation <rel_ampl>
[:SENSe]:POWer[:RF]:ATTenuation?
[:SENSe]:POWer[:RF]:ATTenuation:AUTO OFF|ON|0|1
[:SENSe]:POWer[:RF]:ATTenuation:AUTO?
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).
If the attenuator was in Auto, it sets it to Manual.
Some measurements do not support the Auto setting of
measurements, the Auto/Man selection is not available, and the Auto/Man line
on the key disappears.
In dual attenuator configurations, when the electronic attenuator is enabled,
the mechanical attenuator has no auto setting and the Auto/Man line on the
key disappears. The state of Auto/Man is remembered and restored when the
electronic attenuator is once again disabled. This is described in more detail in
the
"Enable Elec Atten" on page 356
See "Attenuator Configurations and Auto/Man" on page 355
information on the Auto/Man functionality of Attenuation.
When (Mech) Atten is in Auto, it uses the following algorithm to determine a
value:
Atten = ReferenceLevel + PreAmpGain + ExternalGain – RefLevelOffset -
MaxMixerLevel + IF Gain.
Limit this value to be between 6 dB and the Max value. No value below 6 dB
can ever be chosen by Auto.
The resulting value is rounded up to the largest value possible given the
attenuation step setting. That is, 50.01 dB would change to 60 dB (for a 10 dB
attenuation step).
The "IF Gain" term in the equation above is either 0 dB or +10 dB, depending
on the settings of FFT IF Gain, Swept IF Gain, max Ref Level and the
Auto/Man setting of Mech Atten.
in single attenuator models. In the
Atten
(Mech) Atten
key description.
. In these
for more