Today we wrap up our interview with Chris Scholz, Product Manager, Vector Network Analyzers, R&S North America, discussing the different approaches to Signal Integrity.
Ed: It’d be great if you could give us a brief comparison on approaches you’ve dealt with.
Chris: Sure! Signal Integrity applications use baseband data with bandwidth up to 10s of GHz impedance, matching of DUTs in Signal Integrity applications is relatively poor. Looking at TRL-based calibration techniques that have been automated by some vendors, these techniques generally fail to provide accurate results beyond a few GHz.
Ed: What’s TRL?
Chris: Thru-reflect line.
For our customers, in-situ de-embedding (ISD) has shown to be the most accurate de-embedding technique available to date. One of the nice side effects of ISD is that it results in causal measurements what are beneficial for further processing standard design tools.
Because the Signal Integrity engineers deal with baseband signals, they face a set of unique challenges that are marginally important for RF engineers. For wireless systems, transmission channels are narrow band and separated from each other.
By contrast, Signal Integrity deals with baseband signals. This means that signals experience impairments that span from close to DC to the maximum frequency that the channel supports. This also means that digital signals are prone to picking up low frequency impairments such as power supply noise, they are prone to frequency dependent loss at high frequencies and they pick up broadband impairments such as various types of crosstalk.