User Manual

45
☞ Definitions
SNR Margin:
Amount of noise (dB loss in SNR) that can be tolerated while maintaining a BER of 10-7.
Line Attenuation:
Measured in dB’s.
Error Seconds:
The time of a received Reed Solomon codeword for data stream indicating that errors have been
corrected in that codeword.
Loss of Signal:
The receiving pilot tone power, averaged over 100 ms, is 6dB or more below the reference power.
Loss of Frame:
When the unit receives two consecutive synchronization symbols, the number of tones with a mismatch
between the expected and the measured bit pattern is lower than the threshold.
CRC Errors:
When a received CRC-8 code for the data stream is not identical to the corresponding generated code at
a rate of at most 1 per super frame (17ms).
Data Rate:
When the router is up, these parameters indicate the actual ATM bit rate (without overheat) for the up
stream / down stream paths.