Unger model

The Unger Model is an empirical standard model for near-end crosstalk (NEXT) power spectra as experienced by communication systems over unshielded twisted pair (UTP).

Twisted pair cables are usually grouped together in a binder where they experience crosstalk. Based on empirical observations, Unger ^[1] proposed that, at the 1% worst case, the NEXT power spectra ${\displaystyle |H_{\mathrm {NEXT} }(f)|^{2}}$, due to a single disturber, can be bounded by

$${\displaystyle 10\log(|H_{\mathrm {NEXT} }(f)|^{2})={\begin{cases}-66+6\log(f)\,{\text{dB}},&{\text{if }}f<20\,{\text{kHz}};\\-50.5+15\log(f)\,{\text{dB}},&{\text{if }}f\geq 20\,{\text{kHz}}.\end{cases}}}$$ while the NEXT power spectra due to 49 disturbers (full binder) can be bounded by

$${\displaystyle 10\log(|H_{\mathrm {NEXT} }(f)|^{2})={\begin{cases}-59.2+4\log(f)\,{\text{dB}},&{\text{if }}f<20\,{\text{kHz}};\\-42.2+14\log(f)\,{\text{dB}},&{\text{if }}f\geq 20\,{\text{kHz}}.\end{cases}}}$$

References

1. J. H. Unger, "Near-End Crosstalk Model for Line Code Studies", ECSA Contribution, T1D1.3/85-244, November 12, 1985.

See also

• Digital subscriber line