14-14
Block Diagram Theory of Operation
Block Diagram 2
A4 Modulation Distribution
A6 Signaling Source/Analyzer
These modules are leveraged from an earlier product, the HP/Agilent 8920A, which is
primarily an analog communications test set. Many of the audio circuits in these
assembliesare not used by the HP/Agilent 8922 and will not be covered in this discussion.
Refer to the HP/Agilent 8920A Assembly Level Repair manual if further detail on these
modules is required.
For the HP/Agilent 8922, the function of the A6 Signaling Source/Analyzer is simply to
createsinusoidal audio signals. The analyzer capabilities of this module are not used in the
HP/Agilent 8922. The A4 Modulation Distribution assembly provides gain, attenuation,
anddistribution functions of these audio signals as well as the AM/Speech input from the
front panel. The interconnection of these modules is shown on Block Diagram 2.
The diagnostic procedures for these modules are extensive. Like the hardware, the
diagnostics have been leveraged from the HP/Agilent 8920A and test more of the circuits
than are actually used in the HP/Agilent 8922. The diagnostic output from these modules
documents the exact circuits in the modules which are tested.