| 摘要 |
PURPOSE:To increase a constant fault detection rate with less test patterns by feeding the output data of a logical package to be tested back, and by varying the appearance possibility of logic 1 as a random-number test pattern according to the output result. CONSTITUTION:Weighted-random-number-signal generating circuits 11-1i generate weighted random number signals 111-1i1 by receiving possibility selection signals 24, 25 and 26 from a 1/2, 3/4 and 7/8 possibility selection register 21 and a logical 1/0 specifying signal 27 from a register 22. Those signals 111-1i1 are inputted to a logical package 30 to be tested, and its output signals 31-3j are compressed by a data compressing circuit 50. Then, counters 41-4j for output variations of the package 30 are read by a microprogram through a signal line 411 to control the weight of random-number generation. |
