Cable De-embedding
Cable de-embedding is a standard feature on all SDA Zi oscilloscopes and is included with Eye Doctor II. Cable de-embedding gives the user the ability to quickly and easily remove the effect of cables by entering in an attenuation table or attenuation constants that are typically provided by the cable manufacturer.
Adding/Removing Pre- or De-emphasis
Serial data channels have a significant impact on the high frequency content of the serial data signal. Therefore, transmitter designers sometime employ the use of emphasis to pre-compensate for these effects. Eye Doctor II can remove de-emphasis or pre-emphasis from a signal measured at the transmitter output. This is useful when attempting to measure the jitter on such a signal in order to remove the DDj introduced by the de-emphasis. Additionally, Eye Doctor II can add de-emphasis or pre-emphasis to identify the amount necessary to compensate for specific serial data channels.
Cable/Fixture/Serial Data Channel De-embedding
In many typical high frequency measurement situations, engineers desire to connect as directly to their signal as possible and avoid the use of probes. However, even high quality test fixtures, channels, and cables have a negative impact on signal quality that increases with higher signal frequency. While these effects could be ignored at lower frequencies, they should always be accounted for as bit rates increase above 5 Gb/s. If the test fixture, channel, or cable can be electrically quantified in terms of S-parameters using Vector Network Analyzers (VNAs), or Time Domain Reflectometer/Time Domain Transmission (TDR/TDT), then the electrical impact of them can be removed from the measurement result. The result is a measurement that is unaltered by the test setup, and the ability to further measure, apply math, or post-process this true measurement using additional built-in oscilloscope tools, such as parameters, math functions, jitter tracks, histograms, eye diagrams, etc.
