ANSI EIA-364-90:2000 pdf download.Crosstalk Ratio Test Procedure for Electrical Connectors, Sockets, Cable Assemblies or Interconnect Systems.
This procedure applies to interconnect assemblies, such as electrical connectors, sockets and cable assemblies.
1.2 Object
This standard describcs test methods for neasuring the magnittide of the electromagnetic coupling between driven and quiet lines of an interconnect assembly. Both iime domain (method A) and frequency domain methods (method B), single-ended and di fterentia.l transmission. and insenicrn and reference fix.ture tecthniques are described.
1.3 Definitions
1.3.1 Drive signal
For thc time domain method, the drive signal is a step waveform. For the frequency domain method, the drive signal is sinusoidal.
1.3.2 Crosstalk ratio
The ratio ci the signal coupled (induced) ino the quiet sgrwi conductor or conductor pair to the magnitude of the signal in the driven conductor or conductor pair. Both signals shall have the same units of either voltage or current, and the ratio may be exprc55ed as percent or lB.
1.3.3 Near end crosstalk ratio (NEXT)
The crosstalk ratio calculacd on (he quiet line at or in proximity to the sending (signal source) end of the driven line. This is the ratio of the near end quiet line signal amplitude to the near end driven line signal amplitude.
1.3.4 Far end crosstalk raiic (TEXT)
The crosstalk raliu ciilculated on the quiet line at or iii proxi mity to the receiving (destination) end of the driven line. This is the ratio of the far end quiet line signal amplitudc to the near cud dnven line signal amp1i(ud.
I .3. Measurement system rise time
Rise time measured with fixture in p(ce, without the specimen, aTid with fi1tring (r normalization). Rise tme i typically rreasuTed from 10% to 90% levels.
1.3.6 Specimen environment impedance
The impedance presented to the specimen signal conductors by the fixture. This impedance is a result of transmission 1iiis, tcrininaticin resistors, attached receivers or signa] sources, and fixture parasitics.
1.3.7 Step amplitudc
Ihe voltage difference between the 0% arid 1OO levels, ignoring ovcrshoot and underht, as indicated iii figure 1.
1.3.8 Isolation standard
A reference fixture without a test specimen and with idenlical rossta1k characteristics as the test fixture. This fixture may or may not be part of the test board.
1.3.9 Termination (eleciicnics usage)
An impedance connected to the end of a tranrnission line, typically tø mrnmize reflected energy on the line.ANSI EIA-364-90 pdf download.