Meaning
Measurement standards for signal integrity on printed circuit boards define electrical characterization methods for test fixtures at frequencies up to fifty gigahertz. High speed digital designs utilize ieee 370 to verify and de-embed test fixtures used in component evaluations.
Test Fixture
Fixture quality dictates whether high speed trace measurements accurately represent the semiconductor device or merely the launch connector. The standard provides math procedures to qualify fixtures as Class A or Class B based on trace return loss and phase consistency. This classification determines whether a fixture is clean enough for mathematical extraction.
Signal Integrity
High frequency data streams require precise phase and amplitude tracking across multiple transmitter pins. If the test channel introduces unknown reflections, simulated eye diagrams will not match physical board measurements. Using standard methods ensures that the measurement plane is moved to the package pins without introducing mathematical errors.
Deembedding Rule
Calibration files must be evaluated using quality metrics like self-consistency and passivity to ensure they do not add fake gain to the measurement. Standard test lines on the board are used to check the mathematical accuracy of the de-embedding algorithm. If the resulting traces violate conservation of energy, the measurement is flagged as invalid.
This check prevents engineers from making development decisions on corrupted fixture datasets.
