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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 8. Signal spectrum before and after adaptive filtering
(a)Before adaptive filtering(b)After adaptive filtering
Extracts from the Article
要观察实际的滤除效果可以通过文本文档,将功能仿真结果导入MATLAB中并观察信号频谱。图8为自适应滤波前后的信号频谱,可以看到2 MHz分量已被有效滤除。
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