Event based test system data memory compression

Abstract

An event based test system for storing event data in a compressed form to reduce the size of a memory and decompressing the data to produce the events for testing a device under test (DUT). The event based test system includes a clock count memory for storing clock count data of each event wherein the clock count data is formed of one or more data words depending on the value of the integral part data, a vernier data memory for storing vernier data of each event wherein the vernier data memory stores vernier data for two or more events in the same memory location, an address sequencer for generating address data for accessing the clock count memory and the vernier data memory, a decompressor for reproducing the clock count data from the clock count memory and the vernier data from the vernier data memory corresponding to each event. The event based test system may further include an event process controller for producing an overall delay time of each event relative to a predetermined reference point based on the clock count data and vernier data from the decompressor, and a fine delay controller for generating each event based on the overall delay time to produce test signals for testing the DUT.