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某些监视雷达要求发射的信号是连续波(CW)且为宽带,以满足距离和距离变化率的分辨力;并且,在地面反射物、多目标或其它外界干扰下,也能满足性能要求。虽然一部未调制的CW雷达,同样适合作距离变化率(多卜勒)的测量,而为了测距通常要求对发射信号进行调制。本文描述伪随机码(P R C)应用它调制在雷达发射机载波上满足距离分辨和测量的要求。介绍了P R C编码参数的折衷选择方法及其功能。值得指出的是,为了达到要求的性能,必须避免多卜勒的模糊。而这个多卜勒模糊通常使距离测量产生模糊。距离模糊能够通过在照射目标的期间内参差码钟频的方法消除,特别强调的是算法问题,它使得距离测量能做到一个码比特的精度。
Some surveillance radars are required to transmit signals that are continuous wave (CW) and wideband to meet the resolution of distance and distance rate of change; and that meet performance requirements with surface reflections, multiple targets or other external disturbances. Although an unmodulated CW radar is also suitable as a measure of the rate of change of distance (Doppler), the transmitted signal is usually required to be modulated for ranging. This article describes the application of pseudorandom code (P R C) modulation to meet the requirements of distance resolution and measurement on radar transmitter carriers. The eclectic selection method and its function of P R C coding parameters are introduced. It is worth noting that in order to achieve the required performance, Doppler ambiguity must be avoided. This Doppler ambiguity usually blurs the distance measurement. Distance blur can be eliminated by differentiating the code clock frequency during the irradiation of the target, with particular emphasis on algorithmic issues, which enables the distance measurement to achieve a code bit accuracy.