jgg     2010 30 (Supp.2):  105-108    ISSN: 0412-1961  CN: 21-1139/TG DESIGN OF TESTING SIGNAL SOURCE BASED ON DDS FOR KIS SEISMIC INSTRUMENTATION Fu Hua and Chen Zhigao Institute of Seismology, CEA, Wuhan 430071 Received: 1900-01-01  Revised: 1900-01-01  Online: null Supporting info null