Method for generating similar 8 bit/10bit code and apparatus using the same

PURPOSE: A method and an apparatus for generating similar 8 bit/10 bit codes are provided to measure performance of high speed interface I/O devices such as a serializer by using a test pattern which is similar to the 8 bit/10 bit codes as an input of the serializer. CONSTITUTION: An apparatus(500) for generating similar 8 bit/10 bit codes includes a pseudo random bit stream generator(400) and a similar 8 bit/10 bit code generator(600). The pseudo random bit stream generator generates a parallel pseudo random bit stream having N bits, where N is more than 2. The similar 8 bit/10 bit code generator receives the output of the pseudo random bit stream generator and converts the parallel pseudo random bit stream so that the parallel pseudo random bit stream has M1 consecutive binary values of the pseudo random bit stream, where M1 is a natural number smaller than N.