EoW January 2012

Technical article

Mainly, lay variation signatures are found at the fundamental pair lay length, the twinner bow speed and the pretwist speed. The nominal lay length values are affected by changes in process set points, specifically pretwist ratio and its interaction with bow speed. are relatively small. But there appears to be a relationship between the inputs and the lay lengths that would require further validation for statistical significance. An additional and potentially larger impact to the nominal lay length can be seen between machine types. Subsequent processes can add to or have an impact on the variation signatures. This was evident in the measurement of pairs at cabling. Additional signatures for cabler bow speed and take up spool diameter were seen. Finally, and most importantly, crosstalk performance is significantly affected by the process changes in these experiments. Investigation into the changes in lay length values as well as changes in the variation signatures are needed to verify the contribution from each factor. It is reasonable to assume that there are other process inputs that could have an impact to the lay variation as there are other unexplained signatures seen at both twinning and cabling. Their impact to crosstalk performance would require further investigation. n Quantitatively, these changes

▲ ▲ Figure 11 : Spike at 80 MHz in one trial

▲ ▲ Figure 12 : Spike missing at 80 MHz after pretwist changes

Stephen Pearson Tyco Electronics Greensboro North Carolina USA Email : shpearson@te.com Website : www.te.com

Kenneth E Cornelison Beta LaserMike Dayton Ohio USA Email : ken.cornelison@betalasermike.com Website : www.betalasermike.com

▲ ▲ Figure 13 : Spike reduced at 125 MHz after pretwist changes

85

EuroWire – January 2012