InterRange Instrumentation Group（IRIG-B（AC））code is usually used in the shooting range test for time information transmission and systems time synchronization.According to IRIG-B（AC）code format and modulation pr...InterRange Instrumentation Group（IRIG-B（AC））code is usually used in the shooting range test for time information transmission and systems time synchronization.According to IRIG-B（AC）code format and modulation principle,this paper presents IRIG-B（AC）coding circuit design scheme based on field programmable gate array（FPGA）.The B（AC）code signal is generated by AD7245,a digital-to-analog（D/A）converter.After amplified,the signal can be used directly for system time synchronization,and the amplitude of the signal can be adjusted according to different requirements.The IRIG-B（AC）encoder designed has been verified by test.The test results show that it can output accurate time information and has higher practicality.展开更多
为了进一步提高LDPC码的性能,利用外在信息度(EMD)能准确表示环外节点的情况,构造了优化的LDPC码。同时,对构造过程中出现连通性较差的短环,采用破环(Cyc le Removal)操作来改善二部图局部的连通性。实验结果证明:在码长、码率和度分布...为了进一步提高LDPC码的性能,利用外在信息度(EMD)能准确表示环外节点的情况,构造了优化的LDPC码。同时,对构造过程中出现连通性较差的短环,采用破环(Cyc le Removal)操作来改善二部图局部的连通性。实验结果证明:在码长、码率和度分布相同的情况下,它较好的提高了码的性能。展开更多
基金The 10th Postgraduate Science and Technology Fund of North University of China(No.20131020)
文摘InterRange Instrumentation Group（IRIG-B（AC））code is usually used in the shooting range test for time information transmission and systems time synchronization.According to IRIG-B（AC）code format and modulation principle,this paper presents IRIG-B（AC）coding circuit design scheme based on field programmable gate array（FPGA）.The B（AC）code signal is generated by AD7245,a digital-to-analog（D/A）converter.After amplified,the signal can be used directly for system time synchronization,and the amplitude of the signal can be adjusted according to different requirements.The IRIG-B（AC）encoder designed has been verified by test.The test results show that it can output accurate time information and has higher practicality.
