关键词: 垃圾网络电话, 语音激活检测, VAD序列码, 支持向量机

Abstract: To efficiently detect SPIT calls in telecom network，and solve the contradiction between detection accuracy and efficiency，this paper proposes a new method combining filtering and exact recognition based on the analysis of SPIT characteristics.A simple decision based on VAD is firstly used to filter the suspected SPIT calls，then a SVM-based method is applied to detect the SPIT via speech feature finally.Experimental result shows that this method can efficiently detect SPIT calls with lower computation，which is helpful for real-time application.Moreover，the detection accuracy and real-time efficiency both increase while the speech length increasesing.

Key words: Spam Over Internet Telephony（SPIT）, Voice Activity Detector（VAD）, VAD series code, Support Vector Machine（SVM）