14-2
Block Diagram Theory of Operation
Introduction
Introduction
The HP/Agilent 8922 is a specialized instrument designed to test GSM and PCN mobile
radiosand base station transmitters. The HP/Agilent 8922A contains the analog audio and
RF hardware necessary to generate 0.3 Gaussian Minimum Shift Key (GMSK) signals.
Digitalhardware has been added to the HP/Agilent 8922B to allow it to buffer digital data
from a computer and properly format it for the GSM protocol. The HP/Agilent 8922E/F/
G/H/M/S adds complete digital control and allows it to test a mobile radio by simulating a
calibrated base station. For more information on the capabilities of the HP/Agilent 8922
family of test sets, refer to the appropriate technical data sheets.
The complexity of the HP/Agilent 8922 circuits combined with the convenient modular
architecture, allows the HP/Agilent 8922 to be repaired more quickly and economically
with Assembly Level Repair (ALR). This is the recommended repair strategy, and this
manual is focused to support this type of repair. The block diagram discussion provides
sufficient technical detail to understand the overall hardware of the HP/Agilent 8922 and
allows in-depth troubleshooting to isolate failures to a single assembly.
The primary troubleshooting method for the HP/Agilent 8922 is to use the memory card
diagnosticssupplied with this manual. This section is important reading for anyone trying
to understand the overall hardware of the HP/Agilent 8922, and should be used as a
tutorial or when the diagnostics cannot correctly locate a faulty assembly.