ANSI EIA 364-90-2000 pdf download Crosstalk Ratio Test Procedure for Electrical Connectors, Sockets, Cable Assemblies or Interconnect Systems .
1.1 Scope This procedure applies to interconnect assemblies, such as electrical connectors, sockets and cable assemblies.
1.2 Object This standard describcs test methods for measuring the magnitude of the electromagnetic coupling between driven and quiet lines of an interconnect assembly. Both time domain (method A) and frequency domain methods (method B)， single-ended and differential transmission, and insertion and reference fixture techniques are described.
1.3 Definitions
1》3.1 Drive sigmal . For thc time domain method, the drive signal is a step wavefom. For the frequency domnain method, the drive si gnal is sinusoidal.
1.3.2 Crosstalk ratio The ratio of the signal coupled (induced) into the quiet signal 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 expressed as percent or dB.
1.3.3 Ncar end crosstalk ratio (NEXT) The crosstalk ratio calculatcd on the 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 ratio (FEXT) The crostaIk ratio calculated om the quiet line at or in proximity t0 the rceiving (destination) cnd of the dniven line. This is the ratio of the far end quiet line signal amphitudc to the near end driven line signal amplitude.
1.3.5 Mcasurement system rise time Rise time measured with fixture in place, without the specimen, and with filtring (or normalization). Rise time is typically reasured from I0% to 90% Ievels.
1.3.6 Specimen environment impedance . The impedance presented to the specimen signal conductors by the fixture. This impedance is a result of transmission lincs, tcmination resistors, attached receivers or signal sources. and fixture parasitics.
1.3.7 Step amplitude 1he voltage difference between the 0% and 100% levels, ignoring ovcrshoot and undershoot, as indicated in figure 1.
1.3.8 Isolation standard A reference fixture without a test specimen and with identical crosstalk characteristics as the test fixturc. This fixture may or may not be part of the test board.
1.3.9 Termination (electronics usage) An impedance connected to the end of a transmission line, typically to minimize reflected energy on the line.
2 Test resources
2.1 Equipmeat
2.1.1 Method A, time domain
2.1.1.1 A step generator is used on the driven line and an oscilloscope monitors the quiet line. In a differential application both shal be able to proccss differential signals. Typically, this means complementary outputs with provision for amplitude and skew adjustnent, and dual inputs with a display of the differencc and sum. Filtering or norrnalizalion shall be avai1able for varying the rise time. A time domain reflectometer (TDK) is usually used.