In this work,we analyze and demonstrate a novel photonic-assisted broadband and high-resolution radio frequency(RF) channelization scheme based on dual coherent optical frequency combs(OFCs),regular optical de-muxes,a...In this work,we analyze and demonstrate a novel photonic-assisted broadband and high-resolution radio frequency(RF) channelization scheme based on dual coherent optical frequency combs(OFCs),regular optical de-muxes,and polarization I/Q demodulators in theory and experiment.The use of two coherent combs avoids precise optical alignment,and a numerical filter in digital signal processor(DSP) enables an ideal rectangular frequency response in each channel without any ultra-narrow optical filters.Besides,due to the use of polarization I/Q demodulation,ambiguous frequency estimate in direct detection can be avoided and the amplitude,phase mismatch in traditional I/Q demodulation can be mitigated.In experiment,we use two coherent OFCs with the free spectrum range(FSR) of about 40 GHz to demonstrate the channelization scheme with seven channels,500 MHz channel spacing and frequency coverage from 3.75 GHz to 7.25 GHz.The input RF tones are accurately down-converted to an intermediate frequency(IF) with a maximum frequency error of 110 kHz.Meanwhile,crosstalk and spurious free dynamic range(SFDR) of the scheme are also discussed.展开更多
为提高磁力仪的性能,给出了自主研发的JOM-1型Overhauser磁力仪的工作原理及系统硬件构成,主要介绍了射频激励电路、信号调理电路、工作时序、仪器的噪声水平及实验结果。野外测试表明该仪器实现了数据采集、显示、存储和查看等基本功能...为提高磁力仪的性能,给出了自主研发的JOM-1型Overhauser磁力仪的工作原理及系统硬件构成,主要介绍了射频激励电路、信号调理电路、工作时序、仪器的噪声水平及实验结果。野外测试表明该仪器实现了数据采集、显示、存储和查看等基本功能,信号的初始信噪比为96∶1,约为自主研发的JPM-1型普通质子旋进磁力仪的3倍,灵敏度可达0.14 n T。展开更多
基金supported in part by the Major State Basic Research Development Program of China ("973" Program) (Grant No. 2012CB315705)National Natural Science Foundation of China (Grant Nos. 61107058, 61120106001)+1 种基金the National High Technology Research and Development Program of China ("863" Program) (Grant No. 2011AA010306)the Fundamental Research Funds for the Central Universities of China
文摘In this work,we analyze and demonstrate a novel photonic-assisted broadband and high-resolution radio frequency(RF) channelization scheme based on dual coherent optical frequency combs(OFCs),regular optical de-muxes,and polarization I/Q demodulators in theory and experiment.The use of two coherent combs avoids precise optical alignment,and a numerical filter in digital signal processor(DSP) enables an ideal rectangular frequency response in each channel without any ultra-narrow optical filters.Besides,due to the use of polarization I/Q demodulation,ambiguous frequency estimate in direct detection can be avoided and the amplitude,phase mismatch in traditional I/Q demodulation can be mitigated.In experiment,we use two coherent OFCs with the free spectrum range(FSR) of about 40 GHz to demonstrate the channelization scheme with seven channels,500 MHz channel spacing and frequency coverage from 3.75 GHz to 7.25 GHz.The input RF tones are accurately down-converted to an intermediate frequency(IF) with a maximum frequency error of 110 kHz.Meanwhile,crosstalk and spurious free dynamic range(SFDR) of the scheme are also discussed.
文摘为提高磁力仪的性能,给出了自主研发的JOM-1型Overhauser磁力仪的工作原理及系统硬件构成,主要介绍了射频激励电路、信号调理电路、工作时序、仪器的噪声水平及实验结果。野外测试表明该仪器实现了数据采集、显示、存储和查看等基本功能,信号的初始信噪比为96∶1,约为自主研发的JPM-1型普通质子旋进磁力仪的3倍,灵敏度可达0.14 n T。
