Amplitude Modulation; Pulse Modulation; Option 1E1 Step Attenuator - Keysight Technologies X Series Service Manual

Micro-Deck Assembly
A7 Micro-Deck Assembly Overview
In this frequency range the ALC detector used is on the A7 Micro-Deck and the
modulators are on the A3 RF assembly.
3.2 GHz and Above
In this frequency range the ALC detector and modulator used are both on the
A7 Micro-Deck assembly.
Below 5 MHz the automatic leveling control is handled by feedback loops of
the op-amps that are used for this frequency range.
For external leveling control the same band breaks listed above apply with the
only change being that the ALC detector is always external.

Amplitude Modulation

The modulating drive signal for all amplitude modulation is generated in the
Function Generator / Trigger Control section of the A3 RF assembly. However,
there are ALC modulators that are used to amplitude modulate the output
signal on both the A3 RF assembly and the A7A3 Mod-Filter on the A7
Micro-Deck assembly. The modulators on the A3 RF assembly are used for
frequencies less than 3.2 GHz, while the modulator on the A7 Micro-Deck
assembly is used for frequencies of 3.2 GHz and higher.

Pulse Modulation

The modulating drive signal for all pulse modulation is generated in the
Function Generator / Trigger Control section of the A3 RF assembly. However,
there are pulse modulators on both the A3 RF assembly and the A7A3
Mod-Filter on the A7 Micro-Deck assembly. The modulators on the A3 RF
assembly are used for frequencies less than 3.2 GHz, while the modulator on
the A7 Micro-Deck assembly is used for frequencies of 3.2 GHz and higher.

Option 1E1 Step Attenuator

The automatic leveling control (ALC) system can only control the power level
across a finite range. Instruments with option 1E1 use the A7AT1 Attenuator to
reduce the power level of the signal beyond the range of the ALC modulators.
The A7AT1 Attenuator has five attenuator sections. How these sections are
used to achieve the desired attenuation values is shown in
230 Keysight CXG, EXG, and MXG X-Series Signal Generators Service Guide
Table .