S-parameter characterization of operational transmitters and channels in digital communications systems

摘要

Reflection and transmission characterization, typically performed with network analyzers and time-domain reflectometers, provides valuable insight into the performance of devices and channels in high-speed communications systems. Active transmitters are difficult to evaluate, as the signal from the transmitter corrupts the stimulus signal from the instrumentation. Putting the transmitter in a static state allowed a measurement to be made, but results were questioned, since the static condition may not represent actual usage. This paper will describe a technique that performs full characterization of digital transmitters and channels while in a large signal, operational mode.