Figure B-1. Derivation of ES, BES, SES, and UAS Parameters
Errored Second (ES)
1 or more CRC-6 Errors
or 1 or more OOF
Severely Errored
Second (SES)
320 or more CRC-6 Errors;
or 1 or more OOF
Bursty Errored
Second (BES)
2 to 319 CRC-6 Errors
and no OOF or SES
Count ES
Count BES
Count UAS
Count SES
AND
AND
AND
10 consecutive
10 consecutive
Declare USS
Clear USS
Unavailable Signal
State (USS)
Yes
Yes
Yes
No
No
Yes
NOTES
USS begins with the first of 10 consecutive SES and ends with the first of 10 consecutive non-SES.
Thus, counts must be adjusted accordingly when USS is declared or cleared.
In D4 mode, BPVs are used instead of CRC-6 Errors to derive BES and SES.
Appendix B
ACST-0351-005
Glossary
June 1996
B-4