ANSI EIA 364-108-2000 pdf download Impedance, Reflection Coefficient, Return Loss, and VSWR Measured in the Time and Frequency Domain Test Procedure for Electrical Connectors, Cable A ssemblies or Interconnection Systems
1 Introduction
1.1 Scope
This procedure applies to interconnect assemblies, such as electrical connectors, and cable assemblies.
1.2 Object
This standard describes test methods to measure impedance, reflction cefficient, returm loss, and voltage standing wave ratio (VSWR) in the time and frequency domains.
NOTE一These test methods are witten for test professionals who are knowledgeable in the electronics field and are trained to use the referenced equipment. Because the measurement values are heavily influenced by the fixturing and equipment this method cannot describe all of the possible combinations. The major equipment manufacturers provide Application Notes for more in depth technical description of how to optimize the use of their equipment. It is imperative that the referencing document include the necessary description and sketches for the test professional to understand how to setup and perform the requested measurements.
1.3 Definitions
1.3.1 Measurement system rise time Rise time measured with the fixture in place, without the specimen, and with filtering (or normalization). Rise time is typically measured from 10% to 90% levels.
1.3.2 Specimen environment impedance The impedance presented to the signal conductors by the fixture. This impedance is a result of transmission lines, termination resistors, attached receivers or signal sources, and fixture parasitics.
1.3.7 Scattering parameter (s-parameter), S11
The reflection coficient at the input port of the device under test, defined as the ratio of the reflected voltage to the incident voltage.
1.3.8 Termination (electronics usage)
An impedance connected to the end of a transmissio line, typically to minimize rlflted energy on the line.
1.3.9 Step amplitude
The voltage difference between the 0% and 100% levels, ignoring overshoot and undershoot.
2 Test resources
Care should be taken when establishing the equivalence between time and frequency domain measurements. The relationship between the two is complex and the application of bandwidth = (0.3/rise time) should not be used without further computations and understanding