Adaptive design of digital FIR filter for beamforming with Its application in PSK UWA communication

The frequency response of real weight digital FIR filters used in traditional time domain broadband beamforming structure can´t fit the design requirements well when the ratio of communication band to central frequency is large. This may result in mainbeam aberration and increasing of sidelobe level. In order to solve this problem, a time domain broadband beamforming structure with complex weight digital FIR filters is presented. Also a digital FIR filter design algorithm is proposed and this algorithm is used to design the complex weight FIR filters. Computer simulation is done when the ratio of central frequency to communication band is 0.8 and the results show: the frequency responses of the filters designed by the proposed algorithm fit the requirements well inside the communication band (the error of amplitude responses is less than 0.3dB and the error of phase responses is less than 0.1rad)