EXFO FTB-8510B Guia Del Usuario página 1167

Common Tabs
Client Offset RX
Note: The following frequency measurements are not available with ODUflex
CBR when Frequency Offset Analysis is disabled.
Frequency Offset indicates the offset between the expected rate
specification and the rate of the input signal.
Max. Negative Offset indicates the offset between the expected rate
specification and the smallest rate recorded from the received signal.
Max. Positive Offset indicates the offset between the expected rate
specification and the largest rate recorded from the received signal.
Offset Unit allows the selection of the frequency offset unit. Choices are
bps and ppm. The default setting is ppm.
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SONET/SDH Application