Background: Heavy ion therapy accelerator is introduced to reconstruct a dedicated synchrotron for medical treatment based on HIRFL-CSR (Heavy Ion Research Facility in Lanzhou-Cooling Storage Ring). Synchronous transmission of HIRFL-CSR uses the 400 kHz baseband signal with optical fiber. Purpose: The bandwidth and reliability of heavy ion therapy accelerator need to be improved for practical application. Methods: Differential phase shift keying (DPSK) modulation and demodulation method has been adopted

combined with the parity check

BCH codec

scrambling and frame synchronization system

to improve the reliability of system. Further improvement on both hardware and software implementation is taken to avoid any error in transmission process. Results: Experimental results show that the error times reduced to zero by using two boards to send and receive data. It is proved that the system can transmit data correctly and effectively. Conclusion: The system can accurately finish the data transmission with high reliability for the high-speed data transmission system of the heavy ion therapy accelerator. It has been directly applied to the scene of the heavy ion therapy accelerator. Abstract