ANSI EIA 364-108:2000 pdf free download – Impedance, Reflection Coefficient, Return Loss, and VSWRM easured in the Time and Frequency Domain Test Procedure for Electrical Connectors, Cable Assemblies or Interconnection Systems
2.2.3.1 Time domain
The fixture shall include features such that the ncar and far ends of the specimen may be determined in time; see annex B. The calibration planc should be as close to the specimen as possible. When the fixture inchudes a pc board with line lraces conecting two conncctors, it shall have a reference trace(s) that will allow the measurement syslem rise time tn he measured. The reference trace shall bave starting points and endpoints at the same location as the dUT starting point and end point. This is becausc (he reference trace(s) length shall be the same as the pc board traces.
2.2.3.2 Frequency domain
It is necessary to include fixture fcatures that will allow for the open, short, and load measurements t0 be taken. This may be accomplished by one of two methods. Frstly, provide reference traces that include the open, load and short standards. Secondly, provide an interface where these standards can be applied directly to the end of lhe fixture and immediately before the input plane of the device under test. When using the open/short method, the fixture shall include features such that measurements may be conducted with the far end of the driven line both open- circuited and short-circuited. NOTE- Other calibration techniques (such as Through -Reflect-Line) may be used. The fxture shal incorporate features appropriate to that calibration method(s).
2.2.4 Single endcd
The fixture shall allow one signal line to he drivcn at a time. The far end of the driven line shall be terminated in the specimen environment impedance (typically 50 ohms). It is recommended that a length of tansmission line be added after the sampl: (hat has a propagation dclay greater than twice he measurement system rise time. Unless ocherwise specitied in the referencing document:
一a 1:] signal to ground ratio shall be used,
一designatcdt gruund lincs shall be cummoned ou both be ntear aIldI far end,
一adjacent signal lines shaFl be terminated in the specimen environment impedance.
2.2.5 Differenlial
The fixture shall allow one signal pair to be driven at 2 time. The driven pair shall be terninated in the specimen environment impedance (tpically 100 ohms). It is recommended that a length of trunsmission line be added after the specimen that has a propagation delay greater than twice the measurerment system rise tine. Unless otherwise specified in the referencing document:
一a 2:1 signal to yround ratio shall be usedI (one signal pair for each ground retum),
一designated ground lines shal] be comnoned on both the near and far cnd,
一adjacent signal lines shall be terminated in the specimen environment impedance.
NOTE一For differential applications in the ftequency domain using a 2-port network analyzer, the fixture will include the use of baluns.