当今的信号设计通常使用像简单波形选择的方法。根据这种方法的信号设计步骤

Today's signal design usually uses methods like simple waveform selection. The signal design steps according to this method can be summarized as follows: <br>1. According to the characteristics of the target environment and the performance requirements of the radar, select a relatively suitable signal type. The radar signal is divided into various forms according to the modulation method. According to the resolution characteristics, radar signals are divided into four categories. <br>The first type is a positive-edged fuzzy function signal (for example, a single carrier frequency pulse signal). <br>The second type is the oblique blade-shaped fuzzy function signal (for example, linear FM pulse signal). <br>The third type is nail-shaped fuzzy function signals (such as coherent pulse signals). <br>The fourth category is pushpin-shaped fuzzy function signals (for example, phase-encoded signals). <br>According to the characteristics of the category signal, it is necessary to select the appropriate type that is suitable for the specific target environment characteristics and meets the radar performance requirements. <br>2. Calculate the main parameters of possible signal forms, weigh the complexity of the technical implementation and the size of the system cost, select the appropriate signal form and parameters, and make the system performance indicators meet the requirements. <br>First, according to the requirements of radar ranging resolution and speed resolution, the minimum values ​​of signal bandwidth and time width are determined respectively. Then select the signal type according to the time bandwidth product value. If the product of the broadband is greater than 1, the first type of signal cannot be applied (TB=1). Then calculate other possible signal form parameters to determine the applicable signal form. <br>For the second type of signal, the appropriate resolution unit should be selected according to the interference intensity in the nominal resolution unit to ensure the signal-to-interference ratio of the accuracy detection. In fact, the signal-to-noise ratio of the signal is improved by reducing the overlapping area of ​​the signal blur area and the inevitable clutter area to ensure the detection accuracy. As the distance resolution unit shrinks, the signal bandwidth will widen accordingly. Due to the distance-speed coupling of the second type signal, the two target signals with different t_d and f_d are output through the filter near the tilt axis, and the two peak waveforms completely overlap together and cannot be distinguished. In order to measure distance and speed correctly, it must be transmitted twice. The first FM (frequency modulation) and the second FM have opposite directions, so the signal bandwidth has doubled. In addition, because the wide pulse will produce a relatively large short-range blind zone, the choice of pulse width also needs to meet the nearest distance requirement

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Today's signal design usually uses methods like simple waveform selection. According to this method, the signal design steps can be summarized as follows:<br>1. According to the characteristics of target environment and the performance requirements of radar, select the appropriate signal type. Radar signals are divided into various forms according to modulation methods. According to the resolution characteristics, radar signals are divided into four categories.<br>The first is a sharp edge ambiguity function signal (such as a single carrier frequency pulse signal).<br>The second type is the fuzzy function signal (such as linear FM pulse signal).<br>The third kind of signal is the nail board fuzzy function signal (such as coherent pulse signal).<br>The fourth is the pinned fuzzy function signal (such as phase coded signal).<br>According to the characteristics of the category signals, it is necessary to select the appropriate types which are suitable for the environment characteristics of specific targets and meet the radar performance requirements.<br>2. Calculate the main parameters of possible signal forms, weigh the complexity of technology implementation and the size of system cost, select the appropriate signal form and parameters, and make the system performance index meet the requirements.<br>Firstly, according to the requirements of radar range resolution and velocity resolution, the minimum signal bandwidth and time width are determined respectively. Then the signal type is selected according to the time bandwidth product value. If the product of the wideband is greater than 1, the first type signal (TB = 1) cannot be applied. Then other possible signal form parameters are calculated to determine the applicable signal form.<br>For the second kind of signal, the appropriate resolution unit should be selected according to the interference intensity in the nominal resolution unit, so as to ensure the signal interference ratio of precision detection. In fact, the signal-to-noise ratio (SNR) is improved by reducing the overlapped area between the signal blur area and the inevitable clutter area, so as to ensure the detection accuracy. With the reduction of the range resolution unit, the signal bandwidth will be widened accordingly. Due to the range velocity coupling of the second type signal, t_ D and F_ D. two different target signals are output by the filter near the tilt axis, and the two peak waveforms overlap completely and cannot be distinguished. In order to measure distance and speed correctly, they must be transmitted twice. The first FM (frequency modulation) and the second FM are in the opposite direction, so the signal bandwidth is doubled. In addition, due to the wide pulse will produce a relatively large near-range blind area, so the selection of pulse width also needs to meet the requirements of the nearest distance<br>