共查询到19条相似文献,搜索用时 531 毫秒
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介绍了四相编码信号产生及数字脉压实现的方法,分析了采样起始时刻和多普勒频率对脉压结果的影响,比较了两个信号部分叠加时线性脉压和硬限幅脉压的结果。 相似文献
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从雷达方程的角度讨论雷达作用距离的影响因素.推导了匹配滤波的改善因子,得出了单个脉冲信号的作用距离方程;对比了步进频率信号脉压后和单脉冲脉压信号相参积累后的作用距离;借助计算机仿真对理论推导结果进行验证. 相似文献
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脉冲步进频率信号经过相关解调后其脉内相位保持相对恒定,因此可以对其解调后的信号采取特殊的方式进行采样。但是如果采样点选择不当,可能会在处理时漏掉某些目标。本文在分析脉冲步进频率信号波形的基础上,给出了一个最佳采样时刻。仿真结果表明,最佳采样时刻的采样值可以包含所有目标的信息。 相似文献
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针对以往模拟脉冲激光引信探测系统存在的测距误差较大的缺点,为进一步提高脉冲激光引信的测距精度,设计了一种数字化脉冲激光引信探测系统.该探测系统包括发射、接收和信号处理3部分,其中信号处理部分主要实现脉冲回波信号的高速实时采样与缓存、信噪比增强与时延估计.采用双通道ADC并行采样,实现了以200 MHz的等效采样频率对脉冲回波信号进行高速采样.当脉冲回波信号很微弱时,采用多脉冲相干平均算法提高了其信噪比,增强了对微弱回波信号的检测能力.通过最小二乘时延估计算法得到了回波时延,进而计算得到目标距离.测距实验结果表明:该探测系统测距精度较高,最大测距误差为0.25 m. 相似文献
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A 14-bit 200-MHz Current-Steering DAC With Switching-Sequence Post-Adjustment Calibration 总被引:1,自引:0,他引:1
In this paper, a novel calibration method for high-accuracy current-steering DACs is presented. Different from traditional calibration methods which achieves the calibration by adjusting the current values of the current sources, our method does the calibration by dynamically rearranging the switching sequence of the current sources. Since this resequencing is performed after chip implementation, even random errors can be cancelled. In this way, the total area needed for the current sources can be greatly reduced. The 14-bit DAC has been implemented in a standard 1P6M 0.18-mum CMOS technology. The core area of the chip is around 3 mm2, among which the area of the current-source block is only 0.28 mm2. The measured SFDR is 81.5 dB at 1 MHz signal frequency and 100 MHz sampling frequency. For 2 MHz signal frequency and 200 MHz sampling frequency, the measured SFDR is 78.1 dB. 相似文献
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从雷达动目标信号变换实现相参积累的角度出发,选取4种典型的相参积累方法:短时傅里叶变换(STFT)、维格纳-威利分布(WVD)、平滑伪维格纳-威利分布(SPWVD)及分数阶傅里叶变换(FRFT),并将其应用于雷达动目标检测。重点研究了采样频率、脉冲数、输入信噪比(SNR)对相参积累性能以及动目标检测性能的影响。结果表明,FRFT运算速度相对较慢但适用范围最广,尤其在处理噪声背景较强的信号时,能够有效抑制噪声,且参数估计精确度较高,具有良好的时频聚集性,为雷达相参积累检测的工程化应用提供理论支撑。 相似文献
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Optical down-sampling of wide-band microwave signals 总被引:1,自引:0,他引:1
Juodawlkis P.W. Hargreaves J.J. Younger R.D. Titi G.W. Twichell J.C. 《Lightwave Technology, Journal of》2003,21(12):3116-3124
Phase-encoded optical sampling allows radio-frequency and microwave signals to be directly down-converted and digitized with high linearity and greater than 60-dB (10-effective-bit) signal-to-noise ratio. Wide-band electrical signals can be processed using relatively low optical sampling rates provided that the instantaneous signal bandwidth is less than the Nyquist sampling bandwidth. We demonstrate the capabilities of this technique by using a 60-MS/s system to down-sample two different FM chirp signals: 1) a baseband (0-250 MHz) linear-chirp waveform and 2) a nonlinear-chirp waveform having a 10-GHz center frequency and a frequency excursion of 1 GHz. We characterize the frequency response of the technique and quantify the analog bandwidth limitation due to the optical pulse width. The 3-dB bandwidth imposed by a 30-ps sampling pulse is shown to be 10.4 GHz. We also investigate the impact of the pulse width on the linearity of the phase-encoded optical sampling technique when it is used to sample high-frequency signals. 相似文献
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针对线性调频脉冲压缩雷达参数化检测高速多目标时受到距离徙动、多普勒扩散和速度模糊的影响,该文首先采用联合频域变标脉冲压缩处理与吕方法(2011)实现目标信号的相参积累,然后在其基础上采用基于多普勒频率模糊数搜索的方法完成高速多目标的参数化检测.算法所提出的频域变标脉冲压缩处理可同步完成距离维的徙动补偿与多普勒维的模糊数补偿,降低了实现目标参数化检测的计算复杂度,且由于算法采用相参积累方式,在低信噪比下可以进行精确的目标检测和运动参数估计.相参积累算法运算量分析、计算机仿真以及实测数据处理结果验证了该文所提算法的有效性. 相似文献