Imperfect linear duplication of combinational circuits

Recently, an approach has been used in which the extra test hardware results from the reconfiguration of the circuit under test (CUT). In this case, the number of triggers which can be used for test purposes is given beforehand, and the following problem results: what sort of compression technique for output sequence can be implemented if a compressor is built on the basis of these triggers. In other words, the number of compressor states is given and we have to choose a structure for the compressor. The two most widely used kinds of compressors are as follows: LFSR based signature analyzer and counter based compactor. The main goal of this paper is to show that there are situations when the second method is preferable