I. Introduction
The purpose of a signal integrity measurement system is to allow real-time monitoring of important parameters that characterize the IC's electrical behavior. These parameters give an indication of the chip's robustness and performance during test and debug or in the application. Figure 1 shows an example of different monitors in a CMOS chip. The monitors in a core are connected through a bus to the controller. Different monitors are used to measure different phenomena: cross talk, supply noise, substrate noise, temperature, switching activity, clock duty-cycle, technology parameters etc. Each monitor fits into the standard-cell library design style and affects the total design as little as possible. The monitors operate at the local power supply, generate their own reference values and can be fully switched off All analog sensing and processing as well as the conversion into a digital format is done locally. The output of a monitor is a digital signal, which is transferred to the monitoring processor.