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提出了基于调频Z变换(CZT)的宽带恒定束宽波束形成(CBB)方法:假设在每个子带内,各方位波束的权系数相同,推导得到:每个频率子带的权系数序列与参考频率的权系数序列的频谱相同,而在频率轴上满足比例伸缩关系,比例尺度为参考频率与相应频率子带的中心频率之比。依据此设计思想,给出有效孔径不变的CZT法(CZTIA)和有效孔径变化的CZT法(CZTVA)两种CBB实现方法。它们均是由参考频率的权系数序列,通过设定不同的参数值,采用CZT快速计算各个子带的权系数序列的频谱,然后通过傅里叶反变换便可得到相应频率子带的权系数序列。计算机仿真结果验证了理论分析的正确性。
A wideband constant beamwidth beamforming (CBB) method based on frequency-modulated Z-transform (CZT) is proposed: Assuming that the weight coefficients of all azimuth beams are the same in each subband, the weight coefficient sequences of each frequency subband and reference The frequency weighting coefficient sequence has the same frequency spectrum, and the scaling relationship is satisfied on the frequency axis. The scale ratio is the ratio of the reference frequency to the center frequency of the corresponding frequency sub-band. According to this design idea, two CBB implementations of CZT (CZTIA) with effective aperture and CZT (CZTVA) with effective aperture variation are given. They are all from the reference frequency weight coefficient sequence, by setting different parameter values, using CZT fast calculation of the weight coefficients of each sub-band spectrum, and then through the inverse Fourier transform to get the corresponding frequency sub-band weight coefficient sequence. Computer simulation results verify the correctness of the theoretical analysis.