  The coincidence technique and the coincidence spectroscopy have been
developed and applied for over 40 years. Most of popular coincidence
measurement systems were based on analog electronics techniques such as time to
amplitude conversion (TAC) or logic selecting coincidence unit. The
above-mentioned systems are relatively cumbersome and complicated to use. With
the strong growth of digital electronics techniques and computational science,
the coincidence measurement systems will be constructed simpler but more
efficient with the sake of application. This article presents the design
principle and signal processing of a simple two-channel coincidence system by a
technique of Digital Signal Processing (DSP) using Field Programmable Gate
Arrays (FPGA) devices at Nuclear Research Institute (NRI), Dalat.
