{"id":8295,"date":"2024-04-24T16:01:01","date_gmt":"2024-04-24T08:01:01","guid":{"rendered":""},"modified":"2024-04-24T16:01:01","modified_gmt":"2024-04-24T08:01:01","slug":"webrtc\u4e2d\u7684\u566a\u58f0\u6291\u5236\u4e4b\u4e00\uff1a\u9891\u57df\u7ef4\u7eb3\u6ee4\u6ce2","status":"publish","type":"post","link":"https:\/\/mushiming.com\/8295.html","title":{"rendered":"webrtc\u4e2d\u7684\u566a\u58f0\u6291\u5236\u4e4b\u4e00\uff1a\u9891\u57df\u7ef4\u7eb3\u6ee4\u6ce2"},"content":{"rendered":"

\n <\/path> \n<\/svg> <\/p>\n

webrtc\u4e2d\u7684\u566a\u58f0\u6291\u5236\u4e4b\u4e00\uff1a\u9891\u57df\u7ef4\u7eb3\u6ee4\u6ce2<\/h2>\n

\u524d\u8a00<\/h3>\n

\u5728\u5f00\u6e90\u7684\u566a\u58f0\u6291\u5236\u7b97\u6cd5\u4e2d,webrtc ns\u662f\u5f88\u6709\u540d\u7684,\u793e\u533a\u91cc\u4e5f\u6709\u5f88\u591a\u5206\u4eab\u7684\u6587\u7ae0,\u4f46\u8981\u4e48\u6df1\u8981\u4e48\u6d45,\u8fd8\u6709\u4e00\u4e9b\u8bef\u5bfc\u8bfb\u8005\u7684,\u6240\u4ee5\u8d81\u7740\u79fb\u690d\u9879\u76ee\u7684\u673a\u4f1a,\u4ece\u76f2\u4eba\u6478\u8c61\u5230\u5e96\u4e01\u89e3\u725b\u7684\u5b66\u4e60\u4e00\u756a\u8fd9\u91cc\u9762\u7684\u7b97\u6cd5\u539f\u7406\u548c\u5de5\u7a0b\u5b9e\u73b0\u3002
WebRtc Ns\u6a21\u5757\u91c7\u7528\u7684\u662f\u9891\u57df\u7ef4\u7eb3\u6ee4\u6ce2\u7684\u65b9\u6cd5\uff0c\u7ed3\u5408VAD\u68c0\u6d4b\u5f97\u5230\u524d\u9a8c\u4fe1\u566a\u6bd4\u548c\u540e\u9a8c\u4fe1\u566a\u6bd4\uff0c\u7b97\u51fa\u9891\u57df\u7ef4\u7eb3\u6ee4\u6ce2\u5668\u7684\u7cfb\u6570\uff0c\u5728\u9891\u57df\u5b9e\u73b0\u4e86\u566a\u58f0\u7684\u6ee4\u9664\u3002\u8be5\u6a21\u5757\u6709\u5b9a\u70b9\u548c\u6d6e\u70b9\u4e24\u90e8\u5206\u4ee3\u7801\uff0c\u5176\u4e2d\u5b9a\u70b9\u4ee3\u7801\u76f8\u5bf9\u6bd4\u8f83\u590d\u6742\uff0c\u800c\u6d6e\u70b9\u4ee3\u7801\u4e3b\u8981\u5206WebRtcNs_AnalyzeCore\u548cWebRtcNs_ProcessCore\u4e24\u90e8\u5206\u6a21\u5757\uff0c\u5148\u5206\u6790\u5f53\u524d\u5e27\uff0c\u518d\u5bf9\u5f53\u524d\u5e27\u8fdb\u884c\u6ee4\u6ce2\uff0c\u7ed3\u6784\u6e05\u6670\uff0c\u65b9\u4fbf\u9605\u8bfb\u548c\u5b66\u4e60\uff0c\u6240\u4ee5\u672c\u6587\u7814\u7a76\u6d6e\u70b9\u4ee3\u7801\u7684\u5b9e\u73b0\u3002<\/p>\n

\u9891\u57df\u7ef4\u7eb3\u6ee4\u6ce2\u5668<\/h3>\n

\u4f7f\u7528\u7ef4\u7eb3\u6ee4\u6ce2\u8fdb\u884c\u8bed\u97f3\u964d\u566a\u7684\u8fc7\u7a0b\uff0c\u5176\u5b9e\u662f\u628a\u964d\u566a\u8fc7\u7a0b\u89c6\u4e3a\u4e00\u4e2a\u7ebf\u6027\u65f6\u4e0d\u53d8\u7cfb\u7edf\uff0c\u5f53\u5e26\u566a\u8bed\u97f3\u901a\u8fc7\u8fd9\u4e2a\u7cfb\u7edf\u65f6\uff0c\u5728\u5747\u65b9\u8bef\u5dee\u6700\u5c0f\u5316\u51c6\u5219\u4e0b\uff0c\u4f7f\u5f97\u7cfb\u7edf\u7684\u8f93\u51fa\u4e0e\u671f\u671b\u7684\u7eaf\u51c0\u8bed\u97f3\u4fe1\u53f7\u6700\u63a5\u8fd1\u7684\u8fc7\u7a0b\u3002
\u5b9e\u9645\u5f53\u4e2d\u6211\u4eec\u80fd\u89c2\u5bdf\u5230\u7684\u4fe1\u53f7 y ( n ) y(n) <\/span><\/span>y<\/span>(<\/span>n<\/span>)<\/span><\/span><\/span><\/span><\/span>\u662f\u542b\u6709\u566a\u58f0\u7684\u3002 \u5047\u8bbe\u5e26\u566a\u8bed\u97f3\u4fe1\u53f7\u53ef\u4ee5\u8868\u8ff0\u4e3a
y ( n ) = s ( n ) + n ( n ) y(n) = s(n)+n(n) <\/span><\/span>y<\/span>(<\/span>n<\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>s<\/span>(<\/span>n<\/span>)<\/span><\/span>+<\/span><\/span><\/span><\/span>n<\/span>(<\/span>n<\/span>)<\/span><\/span><\/span><\/span><\/span><\/span>
s ( n ) s(n) <\/span><\/span>s<\/span>(<\/span>n<\/span>)<\/span><\/span><\/span><\/span><\/span>\u4e3a\u8bed\u97f3\u4fe1\u53f7\uff0c d ( n ) d(n) <\/span><\/span>d<\/span>(<\/span>n<\/span>)<\/span><\/span><\/span><\/span><\/span>\u4e3a\u52a0\u6027\u566a\u58f0\u3002\u7ef4\u7eb3\u6ee4\u6ce2\u65b9\u6cd5\u5c31\u662f\u6d89\u53ca\u4e00\u4e2a\u6570\u5b57\u6ee4\u6ce2\u5668 h ( n ) h(n) <\/span><\/span>h<\/span>(<\/span>n<\/span>)<\/span><\/span><\/span><\/span><\/span>\uff0c\u5f53\u8f93\u5165 y ( n ) y(n) <\/span><\/span>y<\/span>(<\/span>n<\/span>)<\/span><\/span><\/span><\/span><\/span>\u7ecf\u8fc7\u6ee4\u6ce2\u5668\u540e\uff0c\u6ee4\u6ce2\u5668\u7684\u8f93\u51fa\u53ef\u4ee5\u6700\u5927\u7a0b\u5ea6\u7684\u903c\u8fd1 s ( n ) s(n) <\/span><\/span>s<\/span>(<\/span>n<\/span>)<\/span><\/span><\/span><\/span><\/span>\u3002
s ^ ( n ) = y ( n ) \u2217 h ( n ) = \u2211 k = 0 K \u2212 1 y ( n \u2212 k ) h ( k ) \\hat{s}(n)=y(n)*h(n)=\\sum_{k=0}^{K-1} y(n-k)h(k) <\/span><\/span><\/span>s<\/span><\/span><\/span>^<\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>n<\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>y<\/span>(<\/span>n<\/span>)<\/span><\/span>\u2217<\/span><\/span><\/span><\/span>h<\/span>(<\/span>n<\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span><\/span>k<\/span>=<\/span>0<\/span><\/span><\/span><\/span><\/span>\u2211<\/span><\/span><\/span><\/span>K<\/span>\u2212<\/span>1<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>y<\/span>(<\/span>n<\/span><\/span>\u2212<\/span><\/span><\/span><\/span>k<\/span>)<\/span>h<\/span>(<\/span>k<\/span>)<\/span><\/span><\/span><\/span><\/span><\/span>
\u4e0a\u5f0f\u8fdb\u884cDFT\u5f97\u5230
S ^ ( \u03c9 ) = H ( \u03c9 ) Y ( \u03c9 ) \\hat{S}(\\omega)=H(\\omega)Y(\\omega) <\/span><\/span><\/span>S<\/span><\/span><\/span>^<\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>H<\/span>(<\/span>\u03c9<\/span>)<\/span>Y<\/span>(<\/span>\u03c9<\/span>)<\/span><\/span><\/span><\/span><\/span><\/span>
\u5728\u4efb\u610f\u9891\u7387 \u03c9 k \\omega_k <\/span><\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\uff0c\u6211\u4eec\u53ef\u4ee5\u8ba1\u7b97\u51fa\u8bef\u5dee\u4f30\u8ba1
E ( \u03c9 k ) = S ( \u03c9 k ) \u2212 S ^ ( \u03c9 k ) = S ( \u03c9 k ) \u2212 H ( \u03c9 k ) Y ( \u03c9 k ) E(\\omega_k)=S(\\omega_k)-\\hat{S}(\\omega_k)=S(\\omega_k)-H(\\omega_k)Y(\\omega_k) <\/span><\/span>E<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>S<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>\u2212<\/span><\/span><\/span><\/span><\/span>S<\/span><\/span><\/span>^<\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>S<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>\u2212<\/span><\/span><\/span><\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>Y<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span><\/span><\/span>
\u7531\u6b64\u5b9a\u4e49\u9891\u57df\u5747\u65b9\u8bef\u5dee\u7684\u4ee3\u4ef7\u51fd\u6570
J 2 = E [ \u2223 E ( \u03c9 k ) \u2223 2 ] = E { [ S ( \u03c9 k ) \u2212 H ( \u03c9 k ) Y ( \u03c9 k ) ] \u2217 [ S ( \u03c9 k ) \u2212 H ( \u03c9 k ) Y ( \u03c9 k ) ] } = E [ \u2223 S ( \u03c9 k ) \u2223 2 ] \u2212 H ( \u03c9 k ) E [ S \u2217 ( \u03c9 k ) Y ( \u03c9 k ) ] \u2212 H \u2217 ( \u03c9 k ) E [ S ( \u03c9 k ) Y \u2217 ( \u03c9 k ) ] + \u2223 H ( \u03c9 k ) \u2223 2 E [ \u2223 Y ( \u03c9 k ) \u2223 2 ] = E [ \u2223 S ( \u03c9 k ) \u2223 2 ] \u2212 H ( \u03c9 k ) P y s ( \u03c9 k ) \u2212 H \u2217 ( \u03c9 k ) P s y ( \u03c9 k ) + \u2223 H ( \u03c9 k ) \u2223 2 P y y ( \u03c9 k ) \\begin{aligned} J_2&=E[|E(\\omega_k)|^2]\\\\ &=E\\lbrace[S(\\omega_k)-H(\\omega_k)Y(\\omega_k)]^*[S(\\omega_k)-H(\\omega_k)Y(\\omega_k)]\\rbrace\\\\ &=E[|S(\\omega_k)|^2]-H(\\omega_k)E[S^*(\\omega_k)Y(\\omega_k)]-H^*(\\omega_k)E[S(\\omega_k)Y^*(\\omega_k)]+|H(\\omega_k)|^2E[|Y(\\omega_k)|^2]\\\\ &=E[|S(\\omega_k)|^2]-H(\\omega_k)P_{ys}(\\omega_k)-H^*(\\omega_k)P_{sy}(\\omega_k)+|H(\\omega_k)|^2P_{yy}(\\omega_k) \\end{aligned} <\/span><\/span><\/span>J<\/span><\/span>2<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>=<\/span><\/span>E<\/span>[<\/span>\u2223<\/span>E<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>\u2223<\/span><\/span>2<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>]<\/span><\/span><\/span><\/span><\/span><\/span>=<\/span><\/span>E<\/span>{[<\/span>S<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>\u2212<\/span><\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>Y<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>]<\/span><\/span>\u2217<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>[<\/span>S<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>\u2212<\/span><\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>Y<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)]}<\/span><\/span><\/span><\/span><\/span><\/span>=<\/span><\/span>E<\/span>[<\/span>\u2223<\/span>S<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>\u2223<\/span><\/span>2<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>]<\/span><\/span>\u2212<\/span><\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>E<\/span>[<\/span>S<\/span><\/span>\u2217<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>Y<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)]<\/span><\/span>\u2212<\/span><\/span>H<\/span><\/span>\u2217<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>E<\/span>[<\/span>S<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>Y<\/span><\/span>\u2217<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)]<\/span><\/span>+<\/span><\/span>\u2223<\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>\u2223<\/span><\/span>2<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>E<\/span>[<\/span>\u2223<\/span>Y<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>\u2223<\/span><\/span>2<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>]<\/span><\/span><\/span><\/span><\/span><\/span>=<\/span><\/span>E<\/span>[<\/span>\u2223<\/span>S<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>\u2223<\/span><\/span>2<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>]<\/span><\/span>\u2212<\/span><\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>P<\/span><\/span>ys<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>\u2212<\/span><\/span>H<\/span><\/span>\u2217<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>P<\/span><\/span>sy<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>+<\/span><\/span>\u2223<\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>\u2223<\/span><\/span>2<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>P<\/span><\/span>yy<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>
\u516c\u5f0f\u7684\u6700\u540e\u4e00\u884c\u5b9a\u4e49\u4e86 P y y ( \u03c9 k ) = E [ \u2223 Y ( \u03c9 k ) \u2223 2 ] P_{yy}(\\omega_k)=E[|Y(\\omega_k)|^2] <\/span><\/span>P<\/span><\/span>yy<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>E<\/span>[<\/span>\u2223<\/span>Y<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>\u2223<\/span><\/span>2<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>]<\/span><\/span><\/span><\/span><\/span>\uff0c\u53eb\u505a\u4fe1\u53f7\u7684\u529f\u7387\u8c31\u3002 P y s ( \u03c9 k ) = E [ S \u2217 ( \u03c9 k ) Y ( \u03c9 k ) ] P_{ys}(\\omega_k)=E[S^*(\\omega_k)Y(\\omega_k)] <\/span><\/span>P<\/span><\/span>ys<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>E<\/span>[<\/span>S<\/span><\/span>\u2217<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>Y<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)]<\/span><\/span><\/span><\/span><\/span> \u5b9a\u4e49\u4e3a\u8f93\u5165\u4fe1\u53f7 y ( n ) y(n) <\/span><\/span>y<\/span>(<\/span>n<\/span>)<\/span><\/span><\/span><\/span><\/span>\u548c\u671f\u671b\u4fe1\u53f7 s ( n ) s(n) <\/span><\/span>s<\/span>(<\/span>n<\/span>)<\/span><\/span><\/span><\/span><\/span>\u7684\u4e92\u529f\u7387\u8c31\uff0c P s y ( \u03c9 k ) = E [ S ( \u03c9 k ) Y ( \u03c9 k ) \u2217 ] P_{sy}(\\omega_k)=E[S(\\omega_k)Y(\\omega_k)^*] <\/span><\/span>P<\/span><\/span>sy<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>E<\/span>[<\/span>S<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>Y<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>\u2217<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>]<\/span><\/span><\/span><\/span><\/span>\u662f\u4e92\u529f\u7387\u8c31\u7684\u53e6\u5916\u4e00\u79cd\u5f62\u5f0f\uff0c P y s ( \u03c9 k ) = P s y \u2217 ( \u03c9 k ) P_{ys}(\\omega_k)=P_{sy}^*(\\omega_k) <\/span><\/span>P<\/span><\/span>ys<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>P<\/span><\/span>sy<\/span><\/span><\/span><\/span><\/span>\u2217<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span><\/span>\u3002\u5bf9 J 2 J_2 <\/span><\/span>J<\/span><\/span>2<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u6c42\u590d\u5bfc\u6570\uff0c\u5e76\u4ee4\u5176\u7b49\u4e8e0\uff0c\u5f97\u5230\u5982\u4e0b\u7ed3\u679c\uff1a\uff08\u5171\u8f6d\u6c42\u504f\u5bfc\u8fd9\u5757\u6709\u70b9\u6ca1\u7406\u89e3\uff09
\u2202 J 2 \u2202 H ( \u03c9 k ) = H \u2217 ( \u03c9 k ) P y y ( \u03c9 k ) \u2212 P y s ( \u03c9 k ) = [ H ( \u03c9 k ) P y y ( \u03c9 k ) \u2212 P s y ( \u03c9 k ) ] \u2217 = 0 \\frac{\\partial J_2}{\\partial H(\\omega_k)}=H^*(\\omega_k)P_{yy}(\\omega_k)-P_{ys}(\\omega_k)=[H(\\omega_k)P_{yy}(\\omega_k)-P_{sy}(\\omega_k)]^*=0 <\/span><\/span><\/span><\/span>\u2202<\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u2202<\/span>J<\/span><\/span>2<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>=<\/span><\/span><\/span><\/span>H<\/span><\/span>\u2217<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>P<\/span><\/span>yy<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>\u2212<\/span><\/span><\/span><\/span>P<\/span><\/span>ys<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>[<\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>P<\/span><\/span>yy<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>\u2212<\/span><\/span><\/span><\/span>P<\/span><\/span>sy<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span>]<\/span><\/span>\u2217<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>=<\/span><\/span><\/span><\/span>0<\/span><\/span><\/span><\/span><\/span><\/span>
\u7531\u6b64\u5f97\u5230 H ( \u03c9 k ) H(\\omega_k) <\/span><\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span><\/span>\u7684\u7ef4\u7eb3\u89e3\uff1a
H ( \u03c9 k ) = P s y ( \u03c9 k ) P y y ( \u03c9 k ) H(\\omega_k)=\\frac{P_{sy}(\\omega_k)}{P_{yy}(\\omega_k)} <\/span><\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span><\/span><\/span>P<\/span><\/span>yy<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span><\/span><\/span><\/span>P<\/span><\/span>sy<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>
\u5047\u8bbe\u566a\u58f0\u4e3a\u52a0\u6027\u566a\u58f0\uff0c\u4e14\u4e0e\u8bed\u97f3\u4fe1\u53f7\u4e0d\u76f8\u5173
P s y ( \u03c9 k ) = P s s ( \u03c9 k ) P y y ( \u03c9 k ) = P x x ( \u03c9 k ) + P n n ( \u03c9 k ) P_{sy}(\\omega_k)=P_{ss}(\\omega_k)\\\\ P_{yy}(\\omega_k)=P_{xx}(\\omega_k)+P_{nn}(\\omega_k) <\/span><\/span>P<\/span><\/span>sy<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>P<\/span><\/span>ss<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span>P<\/span><\/span>yy<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>P<\/span><\/span>xx<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>+<\/span><\/span><\/span><\/span>P<\/span><\/span>nn<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span><\/span><\/span>
\u4e0a\u5f0f\u4ee3\u5165\u7ef4\u7eb3\u89e3\uff0c\u6211\u4eec\u5f97\u5230\uff1a
H ( \u03c9 k ) = P s s ( \u03c9 k ) P s s ( \u03c9 k ) + P n n ( \u03c9 k ) H(\\omega_k)=\\frac{P_{ss}(\\omega_k)}{P_{ss}(\\omega_k)+P_{nn}(\\omega_k)} <\/span><\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span><\/span><\/span>P<\/span><\/span>ss<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>+<\/span><\/span>P<\/span><\/span>nn<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span><\/span><\/span><\/span>P<\/span><\/span>ss<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>
\u6211\u4eec\u5b9a\u4e49\u8fd9\u79cd\u5f62\u5f0f\u4e3a\u201c\u9891\u57df\u7ef4\u7eb3\u6ee4\u6ce2\u5668\u201d\u3002\u5982\u679c\u5f97\u5230 H ( \u03c9 k ) H(\\omega_k) <\/span><\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span><\/span>\uff0c\u901a\u8fc7\u9891\u57df\u76f8\u4e58\uff0c\u5f88\u5bb9\u6613\u5f97\u5230 S ^ ( \u03c9 ) = H ( \u03c9 ) Y ( \u03c9 ) \\hat{S}(\\omega)=H(\\omega)Y(\\omega) <\/span><\/span><\/span>S<\/span><\/span><\/span>^<\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>H<\/span>(<\/span>\u03c9<\/span>)<\/span>Y<\/span>(<\/span>\u03c9<\/span>)<\/span><\/span><\/span><\/span><\/span>\u3002\u6211\u4eec\u89c2\u5bdf\u9891\u57df\u7ef4\u7eb3\u6ee4\u6ce2\u5668\u7684\u8ba1\u7b97\u516c\u5f0f\uff0c\u53ea\u6d89\u53ca\u5230\u529f\u7387\u8c31\u7684\u8ba1\u7b97\uff0c\u770b\u4e0a\u53bb\u4e5f\u6bd4\u65f6\u57df\u8981\u7b80\u5355\u8bb8\u591a\uff0c\u4f46\u662f\u8bed\u97f3\u4fe1\u53f7\u7684\u77ed\u65f6\u5e73\u7a33\u7279\u6027\uff0c\u4ee4\u6211\u4eec\u6c42\u771f\u5b9e\u7684\u8f93\u5165\u4fe1\u53f7\u529f\u7387\u8c31\u5f88\u9ebb\u70e6\uff0c\u566a\u58f0\u529f\u7387\u8c31\u4e5f\u4e0d\u5bb9\u6613\u5f97\u5230\u3002\u6240\u4ee5\u9700\u8981\u7ee7\u7eed\u63a8\u5bfc\u5bfb\u627e\u8fd1\u4f3c\u903c\u8fd1\u7684\u65b9\u6cd5\u3002\u6211\u4eec\u5b9a\u4e49 \u03be \u03c9 k = \u03be k = P s s ( \u03c9 k ) P n n ( \u03c9 k ) \\xi_{\\omega_k}=\\xi_{k}=\\frac{P_{ss}(\\omega_k)}{P_{nn}(\\omega_k)} <\/span><\/span>\u03be<\/span><\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>=<\/span><\/span><\/span><\/span>\u03be<\/span><\/span>k<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>=<\/span><\/span><\/span><\/span><\/span><\/span>P<\/span><\/span>nn<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>P<\/span><\/span>ss<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u4e3a\u9891\u7387 \u03c9 k \\omega_k <\/span><\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u5904\u7684\u5148\u9a8c\u4fe1\u566a\u6bd4 S N R p r e SNR_{pre} <\/span><\/span>SN<\/span>R<\/span><\/span>p<\/span>re<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\uff0c\u5373\u4fe1\u53f7\u6ca1\u6709\u88ab\u566a\u58f0\u5e72\u6270\u7684\u4fe1\u566a\u6bd4\u3002 \u03b3 \u03c9 k = \u03b3 k = P y y ( \u03c9 k ) P n n ( \u03c9 k ) \\gamma_{\\omega_k}=\\gamma_{k}=\\frac{P_{yy}(\\omega_k)}{P_{nn}(\\omega_k)} <\/span><\/span>\u03b3<\/span><\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>=<\/span><\/span><\/span><\/span>\u03b3<\/span><\/span>k<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>=<\/span><\/span><\/span><\/span><\/span><\/span>P<\/span><\/span>nn<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>P<\/span><\/span>yy<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u4e3a\u9891\u7387 \u03c9 k \\omega_k <\/span><\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u5904\u7684\u540e\u9a8c\u4fe1\u566a\u6bd4 S N R p o s t SNR_{post} <\/span><\/span>SN<\/span>R<\/span><\/span>p<\/span>os<\/span>t<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\uff0c\u5373\u4fe1\u53f7\u5f15\u5165\u52a0\u6027\u566a\u58f0\u540e\u7684\u4fe1\u566a\u6bd4\u3002\u5219 H ( \u03c9 k ) H(\\omega_k) <\/span><\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span><\/span><\/span><\/span>\u53ef\u4ee5\u5199\u6210\u7740\u4e24\u79cd\u4fe1\u566a\u6bd4\u7684\u8868\u8fbe\u65b9\u6cd5\u3002
H ( \u03c9 k ) = \u03be k 1 + \u03be k = 1 \u2212 1 \u03b3 k H(\\omega_k)=\\frac{\\xi_{k}}{1+\\xi_{k}}=1-\\frac{1}{\\gamma_{k}} <\/span><\/span>H<\/span>(<\/span>\u03c9<\/span><\/span>k<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span><\/span><\/span>1<\/span><\/span>+<\/span><\/span>\u03be<\/span><\/span>k<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u03be<\/span><\/span>k<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>=<\/span><\/span><\/span><\/span>1<\/span><\/span>\u2212<\/span><\/span><\/span><\/span><\/span><\/span>\u03b3<\/span><\/span>k<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>1<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>
\u81f3\u6b64\uff0c\u5bf9\u9891\u57df\u7ef4\u7eb3\u6ee4\u6ce2\u5668\u7684\u6c42\u89e3\u53d8\u6210\u4e86\u6c42\u89e3\u4fe1\u53f7\u7684\u5148\u9a8c\u6216\u8005\u540e\u9a8c\u4fe1\u566a\u6bd4\u95ee\u9898\u3002\u770b\u4e0a\u53bb\u96be\u5ea6\u4f3c\u4e4e\u5927\u5927\u964d\u4f4e\u4e86\uff0c\u7136\u800c\u5b9e\u9645\u4e0a\u5bf9\u4e24\u79cd\u4fe1\u566a\u6bd4\u7684\u6c42\u89e3\u4e5f\u975e\u5e38\u56f0\u96be\u3002\u6240\u4ee5\u6709\u7684\u7b97\u6cd5\u5e0c\u671b\u5229\u7528\u4e24\u79cd\u4fe1\u566a\u6bd4\u6765\u5e73\u6ed1\u8ba1\u7b97\u7ed3\u679c\uff0c\u6240\u4ee5\u5f15\u5165\u4e00\u4e2a\u5e73\u6ed1\u56e0\u5b50 \u03b1 \\alpha <\/span><\/span>\u03b1<\/span><\/span><\/span><\/span><\/span>\uff0c\u5bfc\u51fa \uff1a
\u03be i ( k ) = \u03b1 \u03be i ( k ) + ( 1 \u2212 \u03b1 ) \u03be i ( k ) = \u03b1 \u03be i ( k ) + ( 1 \u2212 \u03b1 ) ( \u03b3 i ( k ) \u2212 1 ) \u2248 \u03b1 \u03be i \u2212 1 ( k ) + ( 1 \u2212 \u03b1 ) ( \u03b3 i ( k ) \u2212 1 ) \\begin{aligned} \\xi_i(k)&=\\alpha\\xi_i(k)+(1-\\alpha)\\xi_i(k)\\\\ &=\\alpha\\xi_i(k)+(1-\\alpha)(\\gamma_{i}(k)-1)\\\\ &\\approx\\alpha\\xi_{i-1}(k)+(1-\\alpha)(\\gamma_{i}(k)-1)\\\\ \\end{aligned} <\/span><\/span><\/span>\u03be<\/span><\/span>i<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>k<\/span>)<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>=<\/span><\/span>\u03b1<\/span>\u03be<\/span><\/span>i<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>k<\/span>)<\/span><\/span>+<\/span><\/span>(<\/span>1<\/span><\/span>\u2212<\/span><\/span>\u03b1<\/span>)<\/span>\u03be<\/span><\/span>i<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>k<\/span>)<\/span><\/span><\/span><\/span><\/span><\/span>=<\/span><\/span>\u03b1<\/span>\u03be<\/span><\/span>i<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>k<\/span>)<\/span><\/span>+<\/span><\/span>(<\/span>1<\/span><\/span>\u2212<\/span><\/span>\u03b1<\/span>)<\/span>(<\/span>\u03b3<\/span><\/span>i<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>k<\/span>)<\/span><\/span>\u2212<\/span><\/span>1<\/span>)<\/span><\/span><\/span><\/span><\/span><\/span>\u2248<\/span><\/span>\u03b1<\/span>\u03be<\/span><\/span>i<\/span>\u2212<\/span>1<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>k<\/span>)<\/span><\/span>+<\/span><\/span>(<\/span>1<\/span><\/span>\u2212<\/span><\/span>\u03b1<\/span>)<\/span>(<\/span>\u03b3<\/span><\/span>i<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>k<\/span>)<\/span><\/span>\u2212<\/span><\/span>1<\/span>)<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>
\u56e0\u4e3a\u8ba1\u7b97\u5f53\u524d\u5e27\u7684\u5148\u9a8c\u4fe1\u566a\u6bd4\u662f\u4e00\u4e2a\u975e\u56e0\u679c\u4e8b\u4ef6\uff0c\u6240\u4ee5\u5229\u7528\u4e0a\u6b21\u6ee4\u6ce2\u540e\u7684\u5148\u9a8c\u4fe1\u566a\u6bd4\u5f88\u663e\u7136\u662f\u4e00\u79cd\u6d41\u884c\u7684\u505a\u6cd5\uff0c\u90a3\u4e48\u6700\u540e\u6211\u4eec\u5f97\u51fa\u5148\u9a8c\u4fe1\u566a\u6bd4\u7684\u4f30\u8ba1\u503c\u4e3a\uff1a
\u03be i ^ ( k ) = \u03b1 \u03be i \u2212 1 ( k ) + ( 1 \u2212 \u03b1 ) ( \u03b3 i ( k ) \u2212 1 ) \\hat{\\xi_i}(k)=\\alpha\\xi_{i-1}(k)+(1-\\alpha)(\\gamma_{i}(k)-1) <\/span><\/span><\/span>\u03be<\/span><\/span>i<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>^<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>k<\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>\u03b1<\/span>\u03be<\/span><\/span>i<\/span>\u2212<\/span>1<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>k<\/span>)<\/span><\/span>+<\/span><\/span><\/span><\/span>(<\/span>1<\/span><\/span>\u2212<\/span><\/span><\/span><\/span>\u03b1<\/span>)<\/span>(<\/span>\u03b3<\/span><\/span>i<\/span><\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>k<\/span>)<\/span><\/span>\u2212<\/span><\/span><\/span><\/span>1<\/span>)<\/span><\/span><\/span><\/span><\/span><\/span>
\u8fdb\u800c\u6211\u4eec\u5f97\u51fa\u5f53\u524d\u5e27\u7684\u7ef4\u7eb3\u6ee4\u6ce2\u5668
H ^ ( k ) = \u03be i ^ ( k ) 1 + \u03be i ^ ( k ) \\hat{H}(k)=\\frac{\\hat{\\xi_i}(k)}{1+\\hat{\\xi_i}(k)} <\/span><\/span><\/span>H<\/span><\/span><\/span>^<\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>k<\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span><\/span><\/span>1<\/span><\/span>+<\/span><\/span><\/span>\u03be<\/span><\/span>i<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>^<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>k<\/span>)<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u03be<\/span><\/span>i<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>^<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>k<\/span>)<\/span><\/span><\/span><\/span>\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>
\u6700\u540e\u5229\u7528\u6b64\u516c\u5f0f\u5b9e\u73b0\u9891\u57df\u7684\u7ef4\u7eb3\u6ee4\u6ce2\uff1a
S ^ ( \u03c9 ) = H ( \u03c9 ) Y ( \u03c9 ) \\hat{S}(\\omega)=H(\\omega)Y(\\omega) <\/span><\/span><\/span>S<\/span><\/span><\/span>^<\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c9<\/span>)<\/span><\/span>=<\/span><\/span><\/span><\/span>H<\/span>(<\/span>\u03c9<\/span>)<\/span>Y<\/span>(<\/span>\u03c9<\/span>)<\/span><\/span><\/span><\/span><\/span><\/span>
\u53ef\u4ee5\u770b\u51fa\uff0c\u8fd9\u548c\u65f6\u57df\u4ece\u7ef4\u7eb3\u89e3\u5bfc\u51fa\u81ea\u9002\u5e94\u6ee4\u6ce2\u7684\u8fc7\u7a0b\u8fd8\u662f\u6709\u4e9b\u5dee\u5f02\u7684\u3002\u4ece\u516c\u5f0f\u6211\u4eec\u89c2\u5bdf\u4e24\u70b9\u7ed3\u8bba\uff1a<\/p>\n

    \n
  1. \u901a\u8fc7\u8be5\u516c\u5f0f\u6211\u4eec\u5c06\u964d\u566a\u95ee\u9898\u8f6c\u5316\u4e3a\u6c42\u89e3\u4fe1\u566a\u6bd4\u95ee\u9898\uff0c\u964d\u4f4e\u4e86\u95ee\u9898\u590d\u6742\u5ea6\u3002<\/li>\n
  2. \u9891\u57df\u7ef4\u7eb3\u6ee4\u6ce2\u9700\u8981\u51c6\u786e\u7684\u4f30\u7b97\u51fa\u5148\u9a8c\u4fe1\u566a\u6bd4\u548c\u540e\u9a8c\u4fe1\u566a\u6bd4\uff0c\u8fd9\u4e24\u4e2a\u503c\u5f97\u51c6\u786e\u7a0b\u5ea6\u548c\u6536\u655b\u901f\u5ea6\u51b3\u5b9a\u4e86\u6ee4\u6ce2\u5668\u4ee5\u53ca\u6574\u4e2a\u964d\u566a\u7b97\u6cd5\u7684\u6027\u80fd\u3002<\/li>\n<\/ol>\n

    WebRtc\u4e2d\u7684WienerFilter<\/h3>\n

    \u4ee5\u4e0b\u662f\u4ee3\u7801<\/p>\n

    \/\/ Estimate prior SNR decision-directed and compute DD based Wiener Filter.\n\/\/ Input:\n\/\/   * |magn| is the signal magnitude spectrum estimate.\n\/\/ Output:\n\/\/   * |theFilter| is the frequency response of the computed Wiener filter.\nstatic void ComputeDdBasedWienerFilter(const NoiseSuppressionC* self,\n                                       const float* magn,\n                                       float* theFilter) {\n  size_t i;\n  float snrPrior, previousEstimateStsa, currentEstimateStsa;\n\n  for (i = 0; i < self->magnLen; i++) {\n    \/\/ Previous estimate: based on previous frame with gain filter.\n    previousEstimateStsa = self->magnPrevProcess[i] \/\n                           (self->noisePrev[i] + 0.0001f) * self->smooth[i];\n    \/\/ Post and prior SNR.\n    currentEstimateStsa = 0.f;\n    if (magn[i] > self->noise[i]) {\n      currentEstimateStsa = magn[i] \/ (self->noise[i] + 0.0001f) - 1.f;\n    }\n    \/\/ DD estimate is sum of two terms: current estimate and previous estimate.\n    \/\/ Directed decision update of |snrPrior|.\n    snrPrior = DD_PR_SNR * previousEstimateStsa +\n               (1.f - DD_PR_SNR) * currentEstimateStsa;\n    \/\/ Gain filter.\n    theFilter[i] = snrPrior \/ (self->overdrive + snrPrior);\n  }  \/\/ End of loop over frequencies.\n}\n<\/code><\/pre>\n
    \u4ece\u4ee3\u7801\u7684\u6838\u5fc3\u884c\u53ef\u4ee5\u770b\u51fa\u8fd9\u4e2a\u548c\u4e0a\u4e00\u7bc7\u7b97\u6cd5\u63a8\u7b97\u7684\u539f\u7406\u4e00\u81f4\uff0c\u662f\u5229\u7528\u4e24\u4e2a\u4fe1\u566a\u6bd4\u7efc\u5408\u5f97\u51fa\u5f53\u524d\u7cfb\u6570\u7684\u529e\u6cd5\u3002\u5177\u4f53\u7ec6\u8282\u5904\u7406\u8fd8\u6709\u4e9b\u5dee\u5f02\uff0c\u6682\u65f6\u6ca1\u6709\u5bf9\u6bd4\uff0c\u5f53\u6211\u4eec\u5b8c\u6210\u5bf9\u6574\u4e2avad\u7edf\u8ba1\u4e0b\u4fe1\u566a\u6bd4\u7684\u8ba1\u7b97\u4e4b\u540e\uff0c\u518d\u56de\u5934\u770b\u770b\u80fd\u5426\u7406\u89e3\u6bcf\u4e00\u6b65\u516c\u5f0f\u7684\u7ec6\u8282\u3002<\/p>\n
    \u5c0f\u7ed3<\/h3>\n
    \u672c\u7bc7\u5b66\u4e60\u548c\u5206\u6790\u4e86WebRtc\u4e2d\u7684\u9891\u57df\u7ef4\u7eb3\u6ee4\u6ce2\u5668\uff0c\u6574\u4e2aNs\u90fd\u662f\u56f4\u7ed5\u7740\u8fd9\u4e2a\u6765\u5de5\u4f5c\u7684\uff0c\u672c\u6587\u53c2\u8003\u4e86\u5f15\u7528\u91cc\u63d0\u5230\u7684\u4e66\u7c4d\u548c\u51e0\u7bc7\u535a\u6587\uff0c\u7279\u6b64\u611f\u8c22\u3002\u6587\u4e2d\u6709\u7eb0\u6f0f\u7684\u5730\u65b9\u975e\u5e38\u6b22\u8fce\u7ea0\u9519\u3002<\/p>\n
    \u5f15\u7528<\/h3>\n
    1.\u300aMATLAB\u5728\u8bed\u97f3\u4fe1\u53f7\u5206\u6790\u4e0e\u5408\u6210\u4e2d\u7684\u5e94\u7528\u300b\u5b8b\u4e4b\u7528 \u5317\u4eac\u822a\u7a7a\u822a\u5929\u5927\u5b66\u51fa\u7248\u793e
     2.\u300a\u4e00\u4e2a\u9891\u57df\u8bed\u97f3\u964d\u566a\u7b97\u6cd5\u5b9e\u73b0\u53ca\u6539\u8fdb\u65b9\u6cd5\u300b https:\/\/www.cnblogs.com\/icoolmedia\/p\/weiner_audio_ns.html
     3.\u300aWebRTC\u4e4bnoise suppression\u7b97\u6cd5\u300bhttps:\/\/blog.csdn.net\/shichaog\/article\/details\/52514816
     4.\u300aWebrtc NS\u6a21\u5757\u7b97\u6cd5\u300bhttps:\/\/blog.csdn.net\/qq_28882043\/article\/details\/80885240
     5.\u300awebrtc \u5355\u901a\u9053\u964d\u566a\u7b97\u6cd5\uff08ANS\uff09\u7b80\u6790\u300bhttps:\/\/blog.csdn.net\/audio_algorithm\/article\/details\/80812408<\/p>\n","protected":false},"excerpt":{"rendered":"webrtc\u4e2d\u7684\u566a\u58f0\u6291\u5236\u4e4b\u4e00\uff1a\u9891\u57df\u7ef4\u7eb3\u6ee4\u6ce2webrtc\u4e2d\u7684\u566a\u58f0\u6291\u5236\u4e4b\u4e00\uff1a\u9891\u57df\u7ef4\u7eb3\u6ee4\u6ce2\u524d\u8a00\u5728\u5f00\u6e90\u7684\u566a\u58f0\u6291\u5236\u7b97\u6cd5\u4e2d,webrtcns\u662f\u5f88\u6709\u540d\u7684...","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[],"_links":{"self":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts\/8295"}],"collection":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/comments?post=8295"}],"version-history":[{"count":0,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts\/8295\/revisions"}],"wp:attachment":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/media?parent=8295"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/categories?post=8295"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/tags?post=8295"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}