提出了一种迭代算法，在FIR数字滤波器的自适应设计过程中自动改变各个频率指标上代价因子的值，最终实现代价因子的最优取值。利用这种改进方法，可以实现FIR数字滤波器和设计指标之间的最佳拟合。给出了两个设计实例，其中幅度响应每倍频程衰减6dB的滤波器，可以用于模拟水声阵列接收的宽带海洋噪声，而高精度时延的滤波器，则可以实现波束形成中所需要的非整数倍采样间隔的时延。

A wide-band beamforming scheme for uniform circular array is proposed to improve the detection performance for weak passive signals in this paper. In our processing scheme, the wide-band signals sampled from the underwater acoustic array are firstly decomposed into different narrow-band signals using FFT, and then the narrow-band high gain beamforming process is performed for each subband of the FFT outputs. The subband beamformer outputs are squared nd summed using the Eckart weighting coefficients. The length of FFT is selected to make every subband satisfy the condition of narrow-band assumption. The fifty percent of overlapping ratio and-30 dB sidelobe level chebyshev window are used for FFT processing to obtain better system performance. This approach was employed to process some wide-band experimental data recorded from a 24-element circular array at a lake in China. Compared to the conventional beamforming, enhanced detection performance is obtained without improving the complexity of realization.

提出了一种任意结构阵列宽带恒定束宽波束形成的新方法。该方法把任意结构阵列的响应向量表示成以Bessel函数为核函数的级数之和，并将高阶项截断，然后把频带内各个频率点上的阵列响应向量转化到参考频率上，从而得到恒定束宽波束形成向量，使得各个频率上的波束和参考波束相同。同时，本文还给出了一种基于自适应处理的参考波束优化方法。结合均匀分布离散圆阵所作的计算机仿真验证了本文所提方法的有效性。

将阵元域高分辨加权子空间拟合算法（wsF算法）推广到了波束域中，利用声系统接收基阵波束输出信息估计目标方位。由于波束输出可以看作是，一个阵元数为波束个数的虚拟阵的阵元输出，而在大多数的水声系统中，参与确定某个来向的信号方位的波束数通常远小于阵元数，从而算法的运算量得以大大降低。针对某水声系统接收基阵波束输出所作的计算机仿真结果表明，波束域wSF算法应用到实际的水声系统时，可以保持其在阵元域中估计目标方位的优越性能。

In this paper, a new method is presented to design low-sidelobe wideband constant beamwidth beamformers (WCBB) in time domain, which alleviates the effect caused by array mismatch errors by applying the measured array models into the design procedure. A combination of FIR filters and digital delay lines is used in the beamformer structure to reduce the order of FIR filters. In FIR filter design, the semi-definite programming is utilized which is able to constrain both the mainlobe shapes and the sidelobe levels within the whole design frequency band. Results from lake experiments with a practical sonar system verified the effectiveness of the proposed method.