PATENT

B. T. Murray, K. Chakrabarty and J. P. Hayes, "Circuit with built-in self test and method thereof", US Patent number 5790562, issued August 4, 1998.

Abstract
A circuit with a built-in self test, comprising: a circuit to be tested; a generating circuit coupled to the circuit to be tested, wherein the generating circuit generates (i) a series of input signals to the circuit to be tested and (ii) a series of reference signals; a space compaction circuit coupled to an output of the circuit to be tested, wherein the space compaction circuit uses a categorized response of the circuit to be tested to compact the output of the circuit to be tested by a maximum ratio and produces a series of output signals when the input signals are applied to the circuit to be tested; an analysis circuit coupled to the space compaction circuit and the generating circuit, providing a signal indicative of error in the circuit to be tested when the output signals fail to correspond to the reference signals.

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