采用IFIR技术的二级FRM滤波器的设计

为获得更好的频率瞄准式干扰效果，需设计一款过渡带尽量窄、带外衰减尽量大的带通滤波器，以避免发射干扰信号时产生的频率泄漏影响对信号的接收。由于现有硬件资源有限，且滤波器过渡带与带外衰减的设计方法无法满足高性能滤波器的设计要求，因此文章采用改进结构的二级有限脉冲响应内插-频率响应屏蔽(Interpolated FiniteImpulse Response-Frequency Response Masking,IFIR-FRM)滤波技术设计高性能带通滤波器，以满足水声对抗器材对频率瞄准技术的性能要求，同时降低了设计复杂度。仿真结果表明，该方法在降低窄带带通FRM滤波器计算复杂度方面效果明显，有效减少了乘法器的使用，降低了目标滤波器设计的阶数，达到频率瞄准式干扰工作模式的技术指标。

Design of two-stage FRM filter with IFIR technology

In order to obtain better frequency aiming jamming effects, it is necessary to design a band-pass filter with a pass-band as narrow as possible and the attenuation outside the pass-band as large as possible, so as to avoid the effect of the transmitting jamming signal leakage on the normal signal reception. Due to limited existing hardware resources and that the existing design method of filter transition band and out-of-band attenuation cannot meet the design requirements of high-performance filters, in this paper, an improved structure designed by the two-stage interpolated finite impulse response-frequency response masking (IFIR-FRM) filtering technique is used for the high-performance band-pass filter to meet the performance requirements of the underwater acoustic countermeasure equipment, while reducing design complexity. The simulation results show that this method is quite effective in reducing the computational complexity of narrow band-pass FRM filter, the order of the target filter and the use of the multiplier units. The required technical indicators of the frequency aiming jamming mode can be achieved.