Signal integrity or SI is a set of measures of the quality of an electrical signal. In digital electronics, a stream of binary values is represented by a voltage (or current) waveform. However, digital signals are fundamentally analog in nature, and all signals are subject to effects such as noise, distortion, and loss. Over short distances and at low bit rates, a simple conductor can transmit this with sufficient fidelity. At high bit rates and over longer distances or through various mediums, various effects can degrade the electrical signal to the point where less-than-ideal conditions (errors) occur, and the system or device fails. Signal integrity engineering is the task of analyzing and mitigating these effects. Signal integrity engineering is an important activity at all levels of electronics packaging and assembly, from internal connections of an integrated circuit (IC), through the package, the printed circuit board (PCB), the backplane, and inter-system connections. While there are some common themes at these various levels, there are also practical considerations, in particular the interconnect flight time versus the bit period, that cause substantial differences in the approach to signal integrity for on-chip connections versus chip-to-chip connections.
Some of the main issues of concern for signal integrity are ringing, crosstalk, ground bounce, distortion, signal loss, and power supply noise.
Read more about Signal Integrity: History, On-chip Signal Integrity, On-die Termination, Chip-to-chip Signal Integrity
Famous quotes containing the words signal and/or integrity:
“The experience of a sense of guilt for wrong-doing is necessary for the development of self-control. The guilt feelings will later serve as a warning signal which the child can produce himself when an impulse to repeat the naughty act comes over him. When the child can produce his on warning signals, independent of the actual presence of the adult, he is on the way to developing a conscience.”
—Selma H. Fraiberg (20th century)
“I expect a time when, or rather an integrity by which, a man will get his coat as honestly and as perfectly fitting as a tree its bark. Now our garments are typical of our conformity to the ways of the world, i.e., of the devil, and to some extent react on us and poison us, like that shirt which Hercules put on.”
—Henry David Thoreau (1817–1862)