lfsr is linear feedback shift register.this is for generating random patterns.There are different types of LFSR. In testing of circuits we have to generate test the patterns for testing.For this we can use LFSR.MISR is multiple input signature register.It is used in the output section of a testing harware.Normally it is used in Built in self Test(BIST).In the output section, the actual output is to be compared with the fault free output for error detection.Here instead of bit to bit comparison, we can convert output bits into a particular function known as signature.This signature is compared with fault free signature.For this conversion into a signature, we can use a MISR