The Process of Signal Integrity in Board Layout – 101
24 Apr 2016
Technology is always evolving in every industry, business, market and field. This makes it challenging for computer system developers to create and maintain digital systems that are not impaired and can be completed to accomplish signal integrity. Since digital technology began, it advanced the information age, creating innovative methods of achieving one’s goals as it relates to computers and software programs. In fact, technology as a whole has remained constant when it comes to meeting the demands of increased bandwidth and added features.
Below are a few tips that you may find useful in making sure that digital signals are clean, offer quick transitions and excellent integrity. It is also important that these digital signals are stable, accurately and timely placed, valid levels of logic and without any transients.
Many digital issues are easy to identify when the user, engineer, or technician is able to probe deeply into why the signal is behaving in a particular way. Digging deeper means being able to view the analog represented in the faulty digital signal. Even though, the issue may seem as if it is a lost digital pulse, the real cause of the bad signal is often because of the characteristics of the analog. In fact, the characteristics of the analog can turn into faulty digital signal if the reduced amplitude signals are transformed into inaccurate logic states. Or it can happen if due to sluggish rise times, the digital pulses experience a time shift.
Assessing the Problem
The first step in assessing these types of problems is to see the digital pulse stream while viewing the analog of the same digital pulses. To discover the root cause of the issues related to signal integrity, most experts use “oscilloscopes.” Using this method helps to analyze the characteristics of the analog. This will then show details of the waveform, and detect the transients. The oscilloscope can help to track the aberrations of the analog and aid the design engineer in finding the problem of the faulty device.
To find what is directly causing the signal integrity problem, the engineer can go as far as to measure and observe the signal. Most measurements are done using logic analyzer in addition to a spectrum analyzer and the oscilloscope. The engineer can use signal sources to do evaluate new systems and new devices. A stress test can provide details about system inputs that are missing and also replicate the device’s sensor signals.
When using the logic analyzer, the engineer can use a trigger to set conditions. When these conditions are met, the logic analyzer will obtain the data and show the results. With the appropriate data, the engineer can then proceed with fixing any errors and ensuring that signal integrity is maintained.