zero n. (pl. zeros, zeroes) 1.【数学】零;零号。 2.零位;零点,起点;(温度表的)零度,冰点;座标原点;无。 3.最低点;【天文学】天底;【航空】零高度。 4.没价值的人[物]。 5.【军事】= zero hour. the absolute zero 【物理学】绝对零度〔-273.16℃〕。 the air zero 原子弹空中爆炸中心。 fly at zero 超低空(1000英尺高度以下的)飞行。 vt. 1.把(调节器等)调整到零位。 2.把…减少到零位。 zero in 1. 调整(枪炮的)射距,把(枪炮等的标尺)调整到标准无风部位瞄准。 2. 把(火力)对准目标 (on)。 zero out 给…以免税待遇(to zero out funding for public broadcasting 对用于公共广播的经费实行免税)。 adj. 1.零(度)的。 2.【气象学】云幕低于50英尺,能见度小于165英尺的。
The cross-zero detection of wavelet transform could detect the gradation image sudden change information, at the same time it could be express the characteristic information the original map ( namely image function plants " jump point " ) 小波过零检测可以很好的检测到灰度图像的突变信息,同时可以很好的表示出原图像灰度跳变(即图像函数种的“拐点”)的特征信息。
Based on mono-pulse radar system and the analysis of terrain echoes, a geometrical model of air to ground ranging is constituted . by using the signals received from the sum and difference channels of terrain follow radar, a group of the expressions for terrain echoes are educed and characteristics of these echoes are obtained . according to the characteristics of the echoes, the theory and method of pass zero detection of difference channel and its applications are discussed in detail 针对一维单脉冲雷达体制,分析了地形目标回波特性;建立了地形跟随雷达空地测距的几何关系;利用雷达收发信号,导出了地形跟随雷达和差接收通道的回波信号表达式,进行了波形仿真,得到了地形跟随雷达的地面散射产生回波在时域中的特性;根据和差回波特性,阐述了差信号过零点检测测距的原理和方法及工程实践中的应用,并给出了真实雷达对外辐射试验的结果,验证了文中的仿真。
In this paper, the real-time detecting method for harmonic current need only that the constructed voltage system be in step with the real voltage system ( which can be obtained by cross-zero detection to voltage waveform ), meanwhile, we have testified in concerned chapter that the phase is not important for the constructed voltage system 本文所提出的谐波电流实时检测方法,其前提只是要求构造系统与原有电压系统同步(这可以通过对电压波形的过零检测来实现),而对于构造系统的相位却没有严格的要求,本文并在相应位置给予了其证明。