为提高运算放大器的带内增益和带宽,提出了一款应用于长期演进(LTE)接收机中宽带Δ-∑模数转换器(ADC)的四级运算放大器.该运算放大器采用前馈Gm-C和密勒补偿相结合的混合型频率补偿方法,以保证运算放大器的稳定性.文中采用0.13μm1P6M ...为提高运算放大器的带内增益和带宽,提出了一款应用于长期演进(LTE)接收机中宽带Δ-∑模数转换器(ADC)的四级运算放大器.该运算放大器采用前馈Gm-C和密勒补偿相结合的混合型频率补偿方法,以保证运算放大器的稳定性.文中采用0.13μm1P6M CMOS工艺设计了一款高性能的四级运算放大器,并将该运算放大器应用于宽带Δ-∑ADC中.测试结果显示:该运算放大器在1.5 V供电电压下可获得72.8 d B的直流增益、442 MHz的增益带宽积和101 V/μs的转换率;在相同的功耗和带宽下,该放大器的带内(0~10 MHz)增益比传统的两级放大器提高了6 d B以上;采用该运算放大器的宽带Δ-∑ADC在10 MHz的信号带宽下具有68 d B的信噪比和78 d B的无杂散动态范围.展开更多
针对脉冲压缩信号和周期调制连续波信号模糊函数的不同,研究伪码调相与线性调频复合调制信号(Pseudo-random Binary Phase Code Combined with Linear Frequency Modulation,PRBC-LFM)的模糊函数特性,通过理论推导、仿真分析比较其脉冲...针对脉冲压缩信号和周期调制连续波信号模糊函数的不同,研究伪码调相与线性调频复合调制信号(Pseudo-random Binary Phase Code Combined with Linear Frequency Modulation,PRBC-LFM)的模糊函数特性,通过理论推导、仿真分析比较其脉冲压缩信号和周期调制连续波信号模糊函数、距离自相关函数及速度自相关函数的区别和联系。结果表明,它们具有完全不同的模糊函数和距离自相关函数;在多目标环境中,PRBCLFM脉冲压缩信号更容易受到"自身杂波"的干扰;而连续波PRBC-LFM信号的距离自相关函数在时延轴具有较低的距离旁瓣,在测距时会出现距离模糊;但这2种信号都保留了伪随机二相编码信号高速度分辨率的特性及调频信号的多普勒不敏感特性,同时由多普勒频移所产生的附加时延也相对很小,符合现代无线电引信高速目标近程探测的要求。展开更多
The generation of continuous spectrum centered at 400 nm from solid thin plates is demonstrated in this work.A continuum covering 365 nm to 445 nm is obtained when 125-µJ frequency-doubled Ti:sapphire laser pulse...The generation of continuous spectrum centered at 400 nm from solid thin plates is demonstrated in this work.A continuum covering 365 nm to 445 nm is obtained when 125-µJ frequency-doubled Ti:sapphire laser pulses are applied to six thin fused silica plates at 1-kHz repetition rate.The generalized nonlinear Schrodinger equation simplified for forward propagation is solved numerically,the spectral broadening with the experimental parameters is simulated,and good agreement between simulated result and experimental measurement is achieved.The variation of electron density in the thin plate and the advantage of a low electron density in the spectral broadening process are discussed.展开更多
文摘为提高运算放大器的带内增益和带宽,提出了一款应用于长期演进(LTE)接收机中宽带Δ-∑模数转换器(ADC)的四级运算放大器.该运算放大器采用前馈Gm-C和密勒补偿相结合的混合型频率补偿方法,以保证运算放大器的稳定性.文中采用0.13μm1P6M CMOS工艺设计了一款高性能的四级运算放大器,并将该运算放大器应用于宽带Δ-∑ADC中.测试结果显示:该运算放大器在1.5 V供电电压下可获得72.8 d B的直流增益、442 MHz的增益带宽积和101 V/μs的转换率;在相同的功耗和带宽下,该放大器的带内(0~10 MHz)增益比传统的两级放大器提高了6 d B以上;采用该运算放大器的宽带Δ-∑ADC在10 MHz的信号带宽下具有68 d B的信噪比和78 d B的无杂散动态范围.
文摘针对脉冲压缩信号和周期调制连续波信号模糊函数的不同,研究伪码调相与线性调频复合调制信号(Pseudo-random Binary Phase Code Combined with Linear Frequency Modulation,PRBC-LFM)的模糊函数特性,通过理论推导、仿真分析比较其脉冲压缩信号和周期调制连续波信号模糊函数、距离自相关函数及速度自相关函数的区别和联系。结果表明,它们具有完全不同的模糊函数和距离自相关函数;在多目标环境中,PRBCLFM脉冲压缩信号更容易受到"自身杂波"的干扰;而连续波PRBC-LFM信号的距离自相关函数在时延轴具有较低的距离旁瓣,在测距时会出现距离模糊;但这2种信号都保留了伪随机二相编码信号高速度分辨率的特性及调频信号的多普勒不敏感特性,同时由多普勒频移所产生的附加时延也相对很小,符合现代无线电引信高速目标近程探测的要求。
基金supported by the National Key Research and Development Program of China(Grant No.2017YFB0405202),the Major Program of the National Natural Science Foundation of China(Grant No.61690221)the General Program of the National Natural Science Foundation of China(Grant No.11774277).
文摘The generation of continuous spectrum centered at 400 nm from solid thin plates is demonstrated in this work.A continuum covering 365 nm to 445 nm is obtained when 125-µJ frequency-doubled Ti:sapphire laser pulses are applied to six thin fused silica plates at 1-kHz repetition rate.The generalized nonlinear Schrodinger equation simplified for forward propagation is solved numerically,the spectral broadening with the experimental parameters is simulated,and good agreement between simulated result and experimental measurement is achieved.The variation of electron density in the thin plate and the advantage of a low electron density in the spectral broadening process are discussed.
