1) Doppler frequency spread
多普勒频扩
2) Doppler spread spectrum
多普勒扩频
3) doppler spread
多普勒扩展
1.
Based on Watterson model,establishs a Simulink HF audio channel model,which can consider HF characters well such as multipath delay,Doppler spread and so on.
基于Watterson模型搭建了能全面考虑短波多径时延、多普勒扩展等特性的Simulink短波语音信道模型,采用1800Hz的单音语音信号作为输入,通过分析和比较输入输出信道信号的时、频特性,验证了模型的可行性,对短波电离层语音信道的研究有一定的参考价值。
2.
The contours of scattering functions were obtained by introducing a smoothing filter algorithm,and the quantitative analysis of average delay,delay spread,Doppler shift,Doppler spread and the rate of change of Doppler shift with respect to delay,was conducted,the effectiveness of simulation channel was proved.
通过引入平滑滤波算法获得散射函数等高线,对平均延时、延时扩展、多普勒频移、多普勒扩展以及多普勒频移随延时变化的特性进行了定量分析,证明了仿真信道的有效性。
4) pulsed wave Doppler
频谱多普勒
1.
Methods Color Doppler flow image(CDFI) combined with pulsed wave Doppler(PW) was used to define the course of vertebral artery and determine the parameters of blood flow for comparative study between two groups: patient group(30 patients with stenotic vertebral artery's inner diameter <2.
8 mm的狭窄患者30例作为病例组,另选健康自愿者30例作为对照组,分别进行彩色多普勒(CDFI)及频谱多普勒(PW)血流显像检查,观察椎动脉走向,测其内径、峰值流速(Vmax)、阻力指数(RI)。
5) Doppler frequency-shift
多普勒频移
1.
This paper introduces the methods of setting the jamming power, azimuth jam-delay, distance jam-delay and Doppler frequency-shift in the process of jamming the general radar.
文中介绍了对常规雷达进行航迹欺骗时,干扰功率、角度干扰时延、距离干扰时延和多普勒频移等干扰参数的设置方法,给出了相关公式。
2.
In the satellite navigation and positioning system,Doppler frequency-shift is the key problems that degrade the performance of satellite receiver.
为了克服多普勒频率偏移的影响,提高接收机的GPS信号捕获速度,对多普勒频移估计算法进行了研究。
3.
The production of Doppler frequency-shift is analyzed under the high dynamic condition.
文章分析了动态环境下多普勒频移的产生,研究了多普勒频移的估算方法并建立了数学模型,在此基础上提出了一种运用DSP结合专用的DDS芯片AD9954模拟多普勒频移的方案。
6) Doppler Spectrum
多普勒频谱
1.
The blood flow of the main renal artery and segmental renal vessels before and after the sclerotherapy were measured by Doppler spectrum, meanwhile, another 20 cases were chosen as c.
结论超声引导下穿刺注射99·9%乙醇治疗肾囊肿是一种安全、微创、高效、经济的治疗方法;多普勒频谱检测肾血流有助于了解肾囊肿对肾脏的影响。
2.
In the algorithm the doppler spectrum of sea clutter is di- vided into the so-called platform motion spectrum and the sea-echo spectrum.
文中提出新的海杂波模拟算法,该算法将海杂波的多普勒频谱分解成平台运动频谱和海面自身运动频谱,通过脱机方式计算这两个频谱分量,从而有效地减少计算量,使模拟能实时完成。
补充资料:多普勒频移
多普勒频移
物理学术语。又称“多普勒频率”。由多普勒效应引起发射频率与运动目标反射波或散射波信号频率之间的频差。反射体引起的多普勒频移(fd)与发射频率(fs)的关系式为fd=(2Vcosθ)·fs,C为声速,V为反射体的运动速度,θ为反射体运动方向与声束指向之间的夹角。取超声诊断中的典型数据可算得血流。胎心检测中的多普勒频移(fd)均在声频范围之内,因此这类诊断仪器均可采用扬声器来监听。
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