{"id":678,"date":"2020-02-07T14:37:45","date_gmt":"2020-02-07T06:37:45","guid":{"rendered":"https:\/\/www.sunjw.cn\/?p=678"},"modified":"2020-02-20T16:19:49","modified_gmt":"2020-02-20T08:19:49","slug":"basics_in_digital_signal_process","status":"publish","type":"post","link":"https:\/\/www.sunjw.cn\/index.php\/2020\/02\/07\/basics_in_digital_signal_process\/","title":{"rendered":"\u6570\u5b57\u4fe1\u53f7\u5904\u7406\u4e2d\u4e00\u4e9b\u57fa\u672c\u6982\u5ff5"},"content":{"rendered":"<p>\u6700\u8fd1\u5728\u770b\u6570\u5b57\u4fe1\u53f7\u5904\u7406\u76f8\u5173\u5185\u5bb9\uff0c\u5176\u4e2d\u9047\u5230\u5404\u79cd\u540d\u8bcd\u6982\u5ff5\u3002\u867d\u7136\u540d\u79f0\u90fd\u542c\u8bf4\u8fc7\u4e5f\u786e\u5b9a\u5b66\u8fc7\uff0c\u8fd9\u4e48\u591a\u5e74\u4e86\u57fa\u672c\u4e00\u70b9\u5370\u8c61\u4e5f\u6ca1\u6709\u4e86\u3002\u4e0b\u9762\u6574\u7406\u4e86\u4e00\u4e9b\u5b66\u4e60\u8fc7\u7a0b\u4e2d\u9047\u5230\u7684\u4e00\u4e9b\u57fa\u672c\u6982\u5ff5\uff0c\u540e\u7eed\u8fd8\u4f1a\u6301\u7eed\u66f4\u65b0\u3002<br \/>\n==================================================================<\/p>\n<p>\u590d\u6570:a+bi<br \/>\n\u6a21:sqrt(a*a+b*b),\u590d\u5e73\u9762\u4e0a\u70b9\u5230\u539f\u70b9\u8ddd\u79bb<br \/>\n\u5171\u8f6d\uff0c\u5b9e\u90e8\u76f8\u540c\uff0c\u865a\u90e8\u76f8\u53cd<br \/>\n\u5bf9\u4e8e\u590d\u9891\u57df\uff0c\u4e00\u4e2a\u9891\u7387\u4e0a\u7684\u6a21\u7684\u5e73\u65b9\uff0c\u8868\u793a\u8fd9\u4e2a\u9891\u7387\u5206\u91cf\u80fd\u91cf\u7684\u5927\u5c0f<\/p>\n<p>\u590d\u6570\u4e58\u6cd5\u7684\u5b9a\u4e49\u4e3a\uff1a(a+bi)(c+di)=(ac-bd)+(bc+ad)i<\/p>\n<p>\u4fe1\u53f7\u7684\u9891\u8c31\u7531\u4e24\u90e8\u5206\u6784\u6210\uff1a\u5e45\u5ea6\u8c31\u548c\u76f8\u4f4d\u8c31\u3002<\/p>\n<p>\u6240\u8c13\u7684\u80fd\u91cf\u8c31\uff0c\u4e5f\u79f0\u4e3a\u80fd\u91cf\u8c31\u5bc6\u5ea6\uff0c\u662f\u6307\u7528\u5bc6\u5ea6\u7684\u6982\u5ff5\u8868\u793a\u4fe1\u53f7\u80fd\u91cf\u5728\u5404\u9891\u7387\u70b9\u7684\u5206\u5e03\u60c5\u51b5\u3002\u4e5f\u5373\u662f\u8bf4\uff0c\u5bf9\u80fd\u91cf\u8c31\u5728\u9891\u57df\u4e0a\u79ef\u5206\u5c31\u53ef\u4ee5\u5f97\u5230\u4fe1\u53f7\u7684\u80fd\u91cf\u3002\u80fd\u91cf\u8c31\u662f\u4fe1\u53f7\u5e45\u5ea6\u8c31\u7684\u6a21\u7684\u5e73\u65b9<\/p>\n<p>\u6240\u8c13\u7684\u529f\u7387\u8c31\uff0c\u4e5f\u79f0\u4e3a\u529f\u7387\u8c31\u5bc6\u5ea6\uff0c\u662f\u6307\u7528\u5bc6\u5ea6\u7684\u6982\u5ff5\u8868\u793a\u4fe1\u53f7\u529f\u7387\u5728\u5404\u9891\u7387\u70b9\u7684\u5206\u5e03\u60c5\u51b5\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u5bf9\u529f\u7387\u8c31\u5728\u9891\u57df\u4e0a\u79ef\u5206\u5c31\u53ef\u4ee5\u5f97\u5230\u4fe1\u53f7\u7684\u529f\u7387\u3002\u4ece\u7406\u8bba\u4e0a\u6765\u8bf4\uff0c\u529f\u7387\u8c31\u662f\u4fe1\u53f7\u81ea\u76f8\u5173\u51fd\u6570\u7684\u5085\u91cc\u53f6\u53d8\u6362\u3002<\/p>\n<p>\u529f\u7387\u8c31\u662f\u529f\u7387\u8c31\u5bc6\u5ea6\u51fd\u6570\uff08PSD\uff09\u7684\u7b80\u79f0\uff0c\u5b83\u5b9a\u4e49\u4e3a\u5355\u4f4d\u9891\u5e26\u5185\u7684\u4fe1\u53f7\u529f\u7387\u3002<br \/>\n\u4e00\u6bb5\u4fe1\u53f7\u7684\u529f\u7387\u8c31\u7b49\u4e8e\u8fd9\u6bb5\u4fe1\u53f7\u81ea\u76f8\u5173\u51fd\u6570\u7684\u5085\u91cc\u53f6\u53d8\u6362\u3002<\/p>\n<p>\u4e92\u76f8\u5173\u51fd\u6570\u662f\u63cf\u8ff0\u968f\u673a\u4fe1\u53f7x(t),y(t)\u5728\u4efb\u610f\u4e24\u4e2a\u4e0d\u540c\u65f6\u523bt1\uff0ct2\u7684\u53d6\u503c\u4e4b\u95f4\u7684\u76f8\u5173\u7a0b\u5ea6\uff0c<br \/>\n\u81ea\u76f8\u5173\u51fd\u6570\u662f\u63cf\u8ff0\u968f\u673a\u4fe1\u53f7x(t)\u5728\u4efb\u610f\u4e24\u4e2a\u4e0d\u540c\u65f6\u523bt1\uff0ct2\u7684\u53d6\u503c\u4e4b\u95f4\u7684\u76f8\u5173\u7a0b\u5ea6\u3002<br \/>\n\u8bbe\u539f\u51fd\u6570\u662ff(t)\uff0c\u5219\u81ea\u76f8\u5173\u51fd\u6570\u5b9a\u4e49\u4e3aR(u)=f(t)*f(-t)\uff0c\u5176\u4e2d*\u8868\u793a\u5377\u79ef\uff1b<br \/>\n\u8bbe\u4e24\u4e2a\u51fd\u6570\u5206\u522b\u662ff(t)\u548cg(t)\uff0c\u5219\u4e92\u76f8\u5173\u51fd\u6570\u5b9a\u4e49\u4e3aR(u)=f(t)*g(-t)\uff0c\u5b83\u53cd\u6620\u7684\u662f\u4e24\u4e2a\u51fd\u6570\u5728\u4e0d\u540c\u7684\u76f8\u5bf9\u4f4d\u7f6e\u4e0a\u4e92\u76f8\u5339\u914d\u7684\u7a0b\u5ea6\u3002<\/p>\n<p>\u504f\u5ea6\uff08Skewness\uff09:\u662f\u63cf\u8ff0\u6570\u636e\u5206\u5e03\u5f62\u6001\u7684\u7edf\u8ba1\u91cf\uff0c\u5176\u63cf\u8ff0\u7684\u662f\u67d0\u603b\u4f53\u53d6\u503c\u5206\u5e03\u7684\u5bf9\u79f0\u6027\uff0c\u7b80\u5355\u6765\u8bf4\u5c31\u662f\u6570\u636e\u7684\u4e0d\u5bf9\u79f0\u7a0b\u5ea6\u3002\u3002<br \/>\n\u504f\u5ea6\u662f\u4e09\u9636\u4e2d\u5fc3\u8ddd\u8ba1\u7b97\u51fa\u6765\u7684\u3002<br \/>\n\uff081\uff09Skewness = 0 \uff0c\u5206\u5e03\u5f62\u6001\u4e0e\u6b63\u6001\u5206\u5e03\u504f\u5ea6\u76f8\u540c\u3002<br \/>\n\uff082\uff09Skewness &gt; 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