mt9079apr1 Zarlink Semiconductor, mt9079apr1 Datasheet - Page 21

• Manufacturer Part Number: mt9079apr1
• Description: Advanced Controller For E1
• Manufacturer: Zarlink Semiconductor

G.821 Bit Error Rate Estimation
A G.821 BERT estimation for an E1 link can be done with either the BERT counter, when it is associated with the
FAS, or the Errored Frame Alignment Signal counter. It should be noted that the BERT counter will be incremented
once for every bit error found in the FAS, and not just once for every FAS in error. The formula for the link BERT
estimation is as follows:
A similar formula can be used with the FAS error counter.
The CRC-4 error counter can also be used for BERT estimation. The formula for BERT estimation using the
CRC-4 error count is as follows:
A similar formula can be used to provide a BERT estimation of the transmit direction by using the E-bit error
counter, EBt.
A more accurate BERT estimation can be done using the Bipolar Violation Error counter. The BPV error counter
will count violations that are not due to HDB3 encoding. The formula for this is as follows:
This assumes that one BPV error will be the result of one bit error.
where:
BERT estimation = BPV Error counter value/(256
where:
where:
256 is the number of bits per basic frame.
8000 is the number of basic frames in one second.
T is the elapsed time in seconds.
N is the number of bits verified (i.e., when the FAS
F is the number of FAS or channels in one second
(i.e., when the FAS is used F= 4000, when a
channel is selected F = 8000).
T is the elapsed time in seconds.
is used N = 7; when a channel is selected N = 8).
received in one second.
T is the elapsed time in seconds.
2048000 is the number of bits that are
BERT estimation = FAS Error counter value/(7
BERT estimation = CEt counter value/(2048000
BERT estimation = BERT counter value/(N
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