ANSI EIA-364-103-1998 pdf download Propagation Delay Test Procedure for Electrical Connectors, Sockets, Cable Assemblies or Interconnection Systems
1 Introduction
1.1 Scope
This standard is applicable to electrical connectors, sockets, cable assemblies or interconnection systems.
1.2 Object
This standard describes a method for measuring the time it takes for a digital signal to propagate from one specified point to a second specified point.
1.2 Definitions
1.2.1 Measurement system rise time
Rise time measured with the fixture in place, without the specimen, and with fltering (or normalization). Rise time is typically measured from 10% to 90 % levels; see fgure 1.
1.2.2 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.
1.2.3 Propagation delay
The time required for a signal to travel between two specified points of an interconnect system;
see fgure 2.
1.2.4 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 Equipment
2.1.1 Pulse generator and oscilloscope, TDR or other suitable equipment with a measurement system rise time less than or equal to the measured propagation delay.
2.1.2 Probes
Probes, where applicable, shall have suitable rise time performance and circuit loading characteristics (resistance and capacitance).
2.2 Material
When the fixture is a printed circuit board, the reference trace and the test trace should be made on the same printed circuit board to reduce any difference in PCB fabrication processes, dielectric material variations, etc.
2.3 Fixture
Unless otherwise specifed in the referencing document the specimen environment impedance shall match the impedance of the test equipment. Typically this will be 50 ohms for singleended measurements and 100 ohms for differential.
2.3.1 Method A single-ended
The fixture shall allow one signal line to be driven at a time. The driven line shall be terminated according to one of the methods of figure A.2 with the specimen environment impedance. Unless otherwise specified a l:1 signal to ground ratio shall be used with each end having all grounds commoned. Each line adjacent to the driven line(s) shall also be terminated in the specimen environment impedance at both near and far ends.
2.3.1.1 Probe technique
The fixture shall be designed to alow the signal to be probed at the two points between which the delay is to be measured; see fgure A1.a.
2.3.1.2 Insertion technique
The fixture shall be designed to allow measurement of propagation delay with and without the specimen; see figure A.1.b.