In this paper,we report the electronics of a timing measurement system of PTB(portable TDC board), which is a handy tool based on USB interface,customized for high precision time measurements without any crates. The time digitization is based on the High Performance TDC Chip(HPTDC).The real-time compensation for HPTDC outputs and the USB master logic are implemented in an ALTERA's Cyclone FPGA.The architecture design and logic design are described in detail.Test of the system showed a time resolution of 13.3 ps.
