Fluke Networks CertiFiber Pro Users Manual - Manual (Page 124)

Versiv Cabling Certification Product Family
Technical Reference Handbook
102
ACR-N (Attenuation to Crosstalk Ratio at the Near End)
ACR-N is like a signal-to-noise ratio. ACR-N values indicate how
the amplitude of signals received from a far-end transmitter
compares to the amplitude of crosstalk produced by near-end
transmissions, as shown in Figure 48. The tester calculates ACR-N
as the difference (in dB) between NEXT and insertion loss. Higher
ACR-N values mean that received signals are much larger than
crosstalk signals. Higher ACR-N values correspond to better
cabling performance.
Figure 49 shows the ACR-N plot. The tester puts the cursor at the
worst margin.
Note
If the ACR-N result is an an , the 4 dB rule applies.
See “About dB Rules” on page 116.
GPU83.EPS
Figure 48. Attenuation to Crosstalk Ratio, Near End (ACR-N)
Near-end
signal input
Far-end
signal input
Crosstalk and
signal received
from the far end
Crosstalk