I understand that Z-line algorithm performs dynamic impedance de-convolution+ and it removes the multiple reflections inherent in a TDR of a multi-segment interconnect. What are the ways to enhance the accuracy of the Z-line algorithm?

I understand that Z-line algorithm performs dynamic impedance de-convolution+ and it removes the multiple reflections inherent in a TDR of a multi-segment interconnect. What are the ways to enhance the accuracy of the Z-line algorithm?

First of all, you need to follow the general good measurement practices, such as keeping your instrument at a stable temperature, well calibrated, making sure your measurements are repeatable and accurate. Beyond this, the following things can help.

• The IConnect software assumes that the very first point in the measurement window is 50 Ohm, which is the default value for the Impedance Box in the Z-Line Computation Window. If you measure that first impedance point on the oscilloscope, and get a number slightly different from 50 Ohm, you should enter that number in the Z-line computation window. If you measure, for example, 50.4 Ohm in the oscilloscope, that can easily account for the difference between 53 and 55 Ohm towards the end of the waveform.
• Use an average impedance reading, never a point reading. Point reading is too susceptible to the local noise on the waveform. You can measure the average value in IConnect by utilizing our Single-Line modeling window. Load the impedance profile into that window, select the segment over which you want to read the impedance, and select Mean value in the Impedance drop down box on the right.