因此，单个发射的雷达脉冲可以写成

Thus, an individual transmitted radar pulsecan be written as

其中，a(t)为恒定幅度脉冲包络，F_t为雷达载波频率，θ(t)可以是常数，也可以表示脉冲的相位调制。

where a(t) is the constant amplitude pulseenvelope, F_t is the radar carrier frequency, and θ(t) may be aconstant or may represent phase modulation of the pulse.

通常假定a(t)为振幅A、持续时间τ秒的理想方形脉冲包络。

It will usually be assumed that a(t) is anideal, square pulse envelope of amplitude A and duration τ seconds.

该信号的瞬时功率为P_s= A²/2。

The instantaneous power of this signal isjust P_s = A²/2.

因为目标和杂波分量是发射脉冲的延迟回波，所以它们也是窄带信号，尽管它们的幅度和相位调制一般会发生变化，例如通过传播损耗和多普勒偏移效应等。

Because the target and clutter componentsare delayed echoes of the transmitted pulse, they are also narrowband signals,although their amplitude and phase modulation will in general be altered, e.g.,by propagation loss and Doppler shift.

接收机噪声表现为加性随机信号。

Receiver noise appears as an additiverandom signal.

因此，从距离R₀= ct₀/2的散射体反射回波的单个脉冲产生的接收信号可以建模为

Thus, the received signal resulting from asingle pulse echoing from a scatterer at range R₀ = ct₀/2can be modeled as

其中n(t) = 接收机噪声

where n(t) =receiver noise

k = 由传播损耗和目标反射率引起的回波幅度因子

k = echo amplitude factor due topropagation losses and target reflectivity

ϕ(t) = 电磁波与目标相互作用引起的回波相位调制

ϕ(t) = echo phase modulation due to targetinteraction

以上这些特性用于估计目标距离、散射强度和径向速度，并抑制干扰和杂波、形成图像等。

These characteristics are used to estimatetarget range, scattering strength, and radial velocity, suppress jamming andclutter, form images, and so forth.

幅度和相位调制函数也决定了测量的距离分辨率ΔR。

The amplitude and phase modulationfunctions also determine the range resolution ΔR of a measurement.

在非成像雷达中，角分辨率和横向距离分辨率由天线方向图的3dB宽度决定。

Resolution in angle and cross range isdetermined by the 3-dB width of the antenna pattern in a nonimaging radar.

为了设计出良好的信号处理算法，需要对处理的信号建立良好的模型。（一定要注意算法与模型的匹配，模型与工程实验数据的匹配！！！）

In order to design good signal processingalgorithms, good models of the signals to be processed are needed.

在本章中，通过给出散射过程对雷达测量的幅度、相位和频率特性影响的模型，来理解与信号处理相关的常见雷达信号特性。

In this chapter, an understanding of commonradar signal characteristics pertinent to signal processing is developed bypresenting models of the effect of the scattering process on the amplitude,phase, and frequency properties of radar measurements.

虽然确定性模型足以满足简单散射体的建模，但可以看到，复杂的实际目标需要对散射过程的统计特性进行描述。

While deterministic models suffice forsimple scatterers, it will be seen that complicated real targets requirestatistical descriptions of the scattering process.

——本文译自Mark A. Richards所著的《Fundamentals of Radar Signal Processing（Second edition）》

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