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Eliminate the Influence of SMPS Ripple Noise for WiFi Receiver with LMS Algorithms
ZHANG Yan,BU Gang,WANG Mingming
Electronic Science and Technology    2019, 32 (1): 11-15.   DOI: 10.16180/j.cnki.issn1007-7820.2019.01.003
Abstract   (413 HTML6 PDF(pc) (1610KB)(36)  

Aim

ing at the problem of ripple when the switching mode power supply was applied to the RF front-end analog circuit, a scheme of eliminating ripple in the digital baseband by using adaptive filtering was proposed. WiFi transceiver system based on IEEE802.11b wireless communication protocol was established by using simulink, and LMS adaptive filter was utilized in digital baseband to suppress the ripple. Simulation results showed that the signal quality could be significantly improved by the adaptive filter. When the ripple amplitude was within 150 mV, the received signal could meet the protocol requirements. Based on these results, an adaptive filter was designed, including both front end and layout. The power consumption analysis showed that the final adaptive filter consumed only 1.35 mW at 33 MHz clock frequency and 1.98 V supply voltage, validating the possibility of using switching mode power supplies for WIFI receivers to achieve significant power savings.


Figure 5. Adaptive notch structure
Extracts from the Article
因为开关电源纹波的主要成分为与开关频率相同的单频噪声,所以选择结构简单的自适应陷波器[11,12]即可。如图5所示,自适应陷波器只需要两个系数,实现代价更小,且易于级联,通用性强。对应自适应滤波器的结构框图如图6所示,取步长为1/32,此时收敛时间为5.53e-4 s,在收敛速度和稳态误差之间取得了平衡。
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