Abstract: A test signal generator 2 comprises a Pseudo Random Binary bit Sequence generator 20 for generating a Pseudo Random Binary bit Sequence in the form of burst while holding the continuity of the code, and intermittently operates in a burst form in response to operation control signals from circuits 22, 24. During one burst duration, a string of Pseudo Random Binary bit Sequence is generated in a certain sequence, where the first codes in the Pseudo Random Binary bit String generated in this burst duration follows the last code of a Pseudo Random Binary bit String generated in the preceding burst duration.