15-12
Diagnostics Theory

GSM and DCS Diagnostic Tests

GSM and DCS Diagnostic Tests
Each of these tests performs a functional check on the instrument by generating a test
signal and looping the signal back to the measurement hardware.
The tests with titles beginning with E are for use with an HP/Agilent 8922E. Tests with
titles beginning with G are for use with an HP/Agilent 8922G. Tests without an E or G
prefix are used with the HP/Agilent 8922F/H/M/S.
The HP/Agilent 8922E/G DCS tests, EDCSDIAG and GDCSDIAG check instruments
that have an HP/Agilent 83220A installed. The HP/Agilent 8922E/G GSM tests
EGSMDIAG and GGSMDIAG are used for instruments without an HP/Agilent 83220A
installed.The HP/Agilent 8922F/H/M/S diagnostic test are also in two forms. GSMDIAG
checks the HP/Agilent 8922F/H/M/S. The diagnostic test DCSDIAG tests either the HP/
Agilent 83220A or the HP/Agilent 83220E, which ever instrument is installed.
Using internal routing and generation, a known bit pattern is modulated and sent to the
AUX RF OUT port of either the HP/Agilent 8922E/F/G/H or the HP/Agilent 83220A.
Withan external connection made to the RF IN/OUT port the instrument demodulates the
signal and performs a BER measurement and DSP measurement. This test provides a
functional test of the assemblies that can not be checked directly as with the other
diagnostic tests. The assemblies checked include the A31 CODEC, the A32 GSM
CONTROLLER, and the A34 GSM RTI. The HP/Agilent 83220A can be further verified
for failure by disconnecting it and running the appropriate GSM test on the HP/Agilent
8922E/F/G/H/M/S. This will show whether the instrument still fails without the HP/
Agilent 83220A. The HP/Agilent 83220E diagnostic tests are less extensive.