A probabilistic test instrument using a ΣΔ-encoded amplitude/phase-signal generation technique

In this paper we present a design and implementation of an instrument that can be used to inject and extract the timing information associated with signals in high-speed transceiver circuits used for data communications. Using statistical methods, the probability distributions associated with these signals can be extracted using some digital logic and various low-pass filter circuits. At the core of this work is the use of ΣΔ encoding techniques to create both the voltage (amplitude) and timing (phase) references, or strobes used in high-speed sampling. Experimental results reveal the sampling time strobe can be programmed over a phase range of 45 degrees with a phase step of 1 degree at a fixed voltage reference. The probabilistic approach is shown to be extendable to input-output based testing, in general.