Agilent Technologies Auroraduet N1726A, Руководство пользователя, Страница: 182 / 507

Issue 01 - 06/99 4 - 41
Testing in Simulate Mode - Section 2
Bit Error Rate Testing (BERT)
aurora
Duet
can perform a Bit Error Rate Test (BERT) to
check the integrity and quality of the physical
communications channel (Layer 1 or the physical wire).
You can use BERT across the B channels to check an
established ISDN link. On a BRI fixed link you can also
perform D channel BERT. In addition, you can perform
BER tests on several channels at once, without using a
protocol.
2
Note
Spectrum B Stimulus users should refer to Testing with
Spectrum B Stimulus in Chapter 4 Section 2.
How BERT Works
aurora
Duet
generates a test pattern and transmits it
repeatedly to another device, which transmits it back.
aurora
Duet
then compares the received pattern with the
original one and determines the rate of bit errors. The
test passes or fails depending on whether errors occur at
the rate you have set to be the ‘fail’ threshold for the line.
Tip
Although you can only perform one BERT at a time, you
can test on two channels at once by running the test over
a looped link.
Remote and local testing
The receiving device may be another device sending a
similar pattern (remote BERT), or your own aurora
Duet
(local BERT) using a self call. On a self call, aurora
Duet
transmits back the received pattern by looping it back to
another B channel.
Chap4s2.PM6 17/06/99, 09:42 41