Nortel DualMode 800, Руководство по обслуживанию

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9-10 Performing tests using a DCSM
411-2051-500 Draft 00.01 November 1999
The MALT and MAHT tests can be invoked in the following ways:
• from a posted transceiver at the VCH MAP level
• from the CTT level (the first available VCH is selected)
• automatically using Table CTTSCHED (also selects first available VCH)
The MALT and MAHT test use the TTT to inject a low and high level (the
level and frequency is determined by the CTTPARMS tuple) audio tone
respectively onto the MTX trunk. The audio tone is looped from the forward
to the reverse audio by the DUT (that is, the TRU) located at the cell site and
the returned level is measured by the TTT. The TTT also makes a
measurement of the noise level accompanying the audio signal at the return
end of the loop. The MALT and MAHT tests do not use the DCSM as part of
the test path. Figure 9-1 shows the test path and the measured path
measurements.
Figure 9-1
MALT and MAHT CTTPARMS Fields
Running the MALT and MAHT test
Before either the MALT or MAHT test is run be sure that the appropriate test
parameters are datafilled in Table CTTPARMS.The MALT test is invoked at
the VCH level of the MAP position on a posted channel. Procedure 9-8 lists
the step by step manual method of invoking the MALT and MAHT tests.
DCSM
DUT
TTT
Loop Loss (measured)
NM
Network
DRU or BST
Far-to-near loss (measured)
Tone injected
Tone measured
and Loop Noise
level (dBrn)
(MTX Switch)
Cell Site ( )
Near to Far Loss (Calculated)