出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Radio transient surveys have been carried out at 1.4 GHz by using eight 20-m dishes at theWaseda Nasu Observatory since 2004. A new observation system was introduced in January 2010. In the new system, a space-based Fast Fourier Transform processor that consisted of a two-step Radix- 4 based on a Field-Programmable Gate Array (FPGA) was introduced; by using this processor, complex A/D conversions with Nyquist rate sampling (20 MHz) could be carried out. The Nyquist rate sampling facilitated the effective integration of sampling data. A regular wide-field survey using the new system was started in April 2010. This survey is the sixth survey that has been carried out since 2004. A new FFT processor enabled the detection of a hitherto undetected fringe of weak flux, with high S/N.
