Automatic emitter recognition is one of the most difficult tasks in the radar signal analysis. In most cases the modern ESM/ELINT systems cannot recognize the different devices of the same type or class. New method of the radar identification with a very high precision recognizing is the specific emitter identification (SEI). The main task is to find nonintentional modulations in the receiving signals. This paper provides an overview of the new methods of measurement emitter signal features parameters in the time and the frequency domain. This paper presents some aspects of radar signal features extraction, election and classification.