内插倍数可变的低滚降成形滤波器的设计与实现

Design and Implementation of Low Roll-off Factor Shaping Filter with Variable Interpolating Multiple

卫星信道带宽资源有限,低滚降成形滤波器技术是提升卫星信道带宽利用率的手段之一,但是采用该项技术需要大量乘法器资源,尤其在符号速率变化较宽的通用调制解调器设计中,其需求的乘法器资源之巨使之很难实现。针对该问题提出一种低滚降成形滤波器的设计方法,通过仿真确定群时延是影响滚降特性的主要因素,选取合适的群时延,把内插技术与多相滤波技术有效结合在一起,有效减少了滤波器消耗的乘法器资源,设计出滚降系数为0.05的成形滤波器,并在硬件平台上实现,已在卫星通信终端中应用,有效提升了卫星信道的利用率。

The bandwidth of satellite channel is limited.And the technology of low roll-off factor shaping filter can improve the bandwidth utilization of satellite channel.But the adoption of this technology requires a lot of multiplier resources,especially in the design of general purpose modem with wide symbol rate variation.The multiplier required is very difficult to realize.A design method of low roll-off shaping filter is presented.And the group delay is determined as the main factor affecting the rolling drop characteristics,and the appropriate group delay is selected.Then the interpolation technology and polyphase filtering technology are effectively combined together,effectively reducing the consumption of filter multiplier resources.The forming filter roll-off coefficient is 0.05,implemented on the hardware platform.The technology has been applied in a satellite communication terminal,able to enhance the efficiency of satellite channel effectively.