共查询到19条相似文献,搜索用时 171 毫秒
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调频连续波(FMCW)激光调制电路是FMCW激光探测系统的重要组成部分。对FMCW激光调制方法进行研究,设计并实现由线性调频信号产生电路和半导体激光器驱动电路组成的激光调制电路,并给出相应的实验结果。其中线性调频信号产生电路采用基于直接数字频率合成技术的集成芯片AD9958进行设计,产生10~110 MHz的锯齿波线性调频信号;半导体激光器驱动电路采用直接电流调制方式,利用线性调频信号对激光载波的强度进行调制,激励激光器出光。测试结果表明:调频连续波激光调制电路能够满足调制频偏100 MHz、调频周期100 s的设计要求。 相似文献
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介绍了一种使用VCO实现调频的锁相环电路并给出了关键技术,变容二极管直接调频和锁相,环路滤波器的设计及实验结果。该电路不仅具有低相位噪声、高稳定载波、很小的非线性失真,而且具有理想的音频调制频响。 相似文献
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Chirped AM激光雷达中线性调频信号的产生 总被引:1,自引:0,他引:1
线性调频强度调制(Chirped AM)激光雷达将微波雷达中调频测距原理巧妙地应用于激光雷达,用一个线性调频的射频副载波调制激光输出强度.介绍了FM测距的基本数学原理,及激光雷达系统的基本构成和工作原理.在分析对比本体制激光雷达中一项关键技术一一线性调频信号产生几种实现方法的基础上,依据直接数字频率合成和正交调制技术,提出了一种宽带线性调频信号产生方案.介绍了信号发生系统的基本结构以及工作原理,探讨了系统实现的关键技术、技术难点及改进办法. 相似文献
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本文在脉冲延迟发生的基础上提供了一种用调相方法实现抖动调制的方案。该采用数字电路,与传统的调频方法比较具有易实现,精度高等优点,并为进一步开发出抖动测试集资打下了基础。 相似文献
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通过向信号源装入波形可以进一步扩展信号源的功能,使其能够实现任意波形的输出。首先将线性调频信号装入信号源,并通过计算机内部的采集卡所采集数据绘制出了实测的波形;然后系统分析了数字下变频及脉冲压缩处理仿真原理;最后,重点对信号源调制到射频的线性调频信号经过收发组件下变频输出的中频信号,以及信号源直接输出的该线性调频信号的波形分别进行脉冲压缩处理仿真。实验表明,在没有信号产生板和脉冲压缩处理板的条件下,能够用该方法来验证收发组件的性能。 相似文献
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频率调制连续波(FMCW)的产生(即FMCW信号源)是声表面波射频识别系统频域采样阅读器的重要组成部分。为了满足扫频速度、带宽和线性度等要求,采用直接数字频率合成器(DDS)与锁相环(PLL)混频,并结合IQ调制的方式设计了超高频FMCW信号源。实际制作了信号源电路,DDS芯片输出I、Q两路正交信号,并分别以差分形式传输至IQ调制芯片进行上变频。测试了DDS输出信号的差分、正交特性,分别对信号源产生的单频信号和扫频信号进行了测试。最后搭建系统对声表面波标签进行测试。测试结果表明信号源设计的有效性。 相似文献
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T. Hoshida H.F. Liu M. Tsuchiya Y. Ogawa T. Kamiya 《Photonics Technology Letters, IEEE》1996,8(9):1160-1162
Negligibly small amplitude modulation and sufficiently low timing jitter are achieved simultaneously in a passively mode-locked monolithic semiconductor laser stabilized by applying an electrical signal at the second subharmonic of the pulse repetition frequency. Nearly transform-limited 33 GHz pulse trains with 0.56 ps timing jitter and -23 dBc amplitude modulation are obtained with 23 dBm driving signals at 16.5 GHz. Detailed investigations are carried out on the dependence of the amplitude modulation and timing jitter on RF driving power for the second- and third-order subharmonic cases. The excellent amplitude modulation property of the second subharmonic case with the specific laser used in this work is ascribed to the frequency response characteristics of the device. 相似文献
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A new discrete‐amplitude pulse width modulation (DAPWM) scheme for a high‐efficiency linear power amplifier is proposed. A radio frequency (RF) input signal is divided into an envelope and a phase modulated carrier. The low‐frequency envelope is modulated so that it can be represented by a pulse whose area is proportional to its amplitude. The modulated pulse has at least two different pulse amplitude levels in order that the duty ratios of the pulse are kept large for small input. Then, an RF pulse train is generated by mixing the modulated envelope with the phase modulated carrier. The RF pulse train is amplified by a switching‐mode power amplifier, and the original RF input signal is restored by a band pass filter. Because duty ratios of the RF pulse train are kept large in spite of a small input envelope, the DAPWM technique can reduce loss from harmonic components. Furthermore, it reduces filtering efforts required to suppress harmonic components. Simulations show that the overall efficiency of the pulsed power amplifier with DAPWM is about 60.3% for a mobile WiMax signal. This is approximately a 73% increase compared to a pulsed power amplifier with PWM. 相似文献