{"id":2474,"date":"2021-08-16T16:26:26","date_gmt":"2021-08-16T08:26:26","guid":{"rendered":"http:\/\/www.zptest.com:8080\/?p=2474"},"modified":"2021-08-16T16:26:26","modified_gmt":"2021-08-16T08:26:26","slug":"window-functions","status":"publish","type":"post","link":"http:\/\/www.zptest.com\/2021\/08\/16\/window-functions\/","title":{"rendered":"\u7a97\u51fd\u6570\u7684\u4f5c\u7528\u4e0e\u5e38\u7528\u7a97\u51fd\u6570\u7684\u9009\u62e9"},"content":{"rendered":"<div class=\"fusion-fullwidth fullwidth-box fusion-builder-row-1 fusion-flex-container nonhundred-percent-fullwidth non-hundred-percent-height-scrolling\" style=\"background-color: #ffffff;background-position: center center;background-repeat: no-repeat;border-width: 0px 0px 0px 0px;border-color:#eae9e9;border-style:solid;\" ><div class=\"fusion-builder-row fusion-row fusion-flex-align-items-flex-start\" style=\"max-width:1216.8px;margin-left: calc(-4% \/ 2 );margin-right: calc(-4% \/ 2 );\"><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-0 fusion_builder_column_1_1 1_1 fusion-flex-column\"><div class=\"fusion-column-wrapper fusion-flex-justify-content-flex-start fusion-content-layout-column\" style=\"background-color:transparent;padding: 0px 0px 0px 0px;\"><div class=\"fusion-text fusion-text-1\"><p>\u7a97\u51fd\u6570\u662f\u51cf\u5c11\u6cc4\u9732\u7684\u6709\u6548\u624b\u6bb5\u4e4b\u4e00\uff0c\u5b83\u901a\u8fc7\u5bf9\u65f6\u57df\u4fe1\u53f7\u8fdb\u884c\u52a0\u6743\uff0c\u5c06\u91c7\u96c6\u5230\u7684\u4fe1\u53f7\u5757\u7531\u975e\u5468\u671f\u4fe1\u53f7\u8f6c\u53d8\u4e3a\u5468\u671f\u4fe1\u53f7\uff0c\u4f7f\u5176\u6ee1\u8db3\u5085\u91cc\u53f6\u53d8\u6362\u7684\u5468\u671f\u6027\u8981\u6c42\u3002<\/p>\n<p><img decoding=\"async\" class=\"aligncenter size-full wp-image-918\" src=\"http:\/\/www.zptest.com\/wp-content\/uploads\/2020\/09\/window_usage.png\" alt=\"\" width=\"424\" height=\"352\" \/><\/p>\n<p>\u52a0\u7a97\u7684\u65b9\u6cd5\u5c31\u662f\u5bf9\u91c7\u96c6\u5230\u7684\u4fe1\u53f7\u8fdb\u884c\u65f6\u57df\u52a0\u6743\uff1a<\/p>\n<span class=\"katex-eq\" data-katex-display=\"true\"> x_{win}(n) = x(n) * win(n) <\/span>\n<p>\u6839\u636e\u5085\u91cc\u53f6\u53d8\u6362\u7684\u6027\u8d28\u53ef\u77e5\uff0c\u65f6\u57df\u4fe1\u53f7\u52a0\u7a97\uff0c\u76f8\u5f53\u4e8e\u4fe1\u53f7\u9891\u8c31\u4e0e\u7a97\u51fd\u6570\u9891\u8c31\u7684\u5377\u79ef\u3002<\/p>\n<p>\u5e38\u7528\u7684\u7a97\u51fd\u6570\u4e3b\u8981\u6709\uff1a<\/p>\n<p>&#8211; \u77e9\u5f62\u7a97<br \/>\n&#8211; \u6c49\u5b81\u7a97<br \/>\n&#8211; \u5e73\u9876\u7a97<br \/>\n&#8211; Blackman-Harris<br \/>\n&#8211; Kaiser-Bessel<\/p>\n<h3>\u77e9\u5f62\u7a97<\/h3>\n<p>\u77e9\u5f62\u7a97\u4e0a\u5404\u70b9\u5747\u662f1\uff0c\u4e5f\u5c31\u662f\u4e0d\u52a0\u7a97\u3002<\/p>\n<span class=\"katex-eq\" data-katex-display=\"true\"> w(n) = 1, n\\in[0, N-1] <\/span>\n<p>\u5176\u4e2d<span class=\"katex-eq\" data-katex-display=\"false\">n<\/span>\u4e3a\u7d22\u5f15\uff0c<span class=\"katex-eq\" data-katex-display=\"false\">N<\/span>\u4e3a\u91c7\u6837\u70b9\u6570\uff0c\u5176\u65f6\u57df\u548c\u9891\u57df\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n<p><img decoding=\"async\" class=\"aligncenter size-full wp-image-919\" src=\"http:\/\/www.zptest.com\/wp-content\/uploads\/2020\/09\/rect.png\" alt=\"\" width=\"710\" height=\"216\" \/><\/p>\n<h3>\u00a0\u6c49\u5b81\u7a97<\/h3>\n<span class=\"katex-eq\" data-katex-display=\"true\"> w(n) = 0.5(1-cos(\\frac{2{\\pi}n}{N-1})), n\\in[0, N-1] <\/span>\n<p><img decoding=\"async\" class=\"aligncenter size-full wp-image-920\" src=\"http:\/\/www.zptest.com\/wp-content\/uploads\/2020\/09\/hanning.png\" alt=\"\" width=\"710\" height=\"216\" \/><\/p>\n<h3>\u5e73\u9876\u7a97<\/h3>\n<span class=\"katex-eq\" data-katex-display=\"true\"> w(n) = (1-1.93cos(\\frac{2{\\pi}n}{N-1})+1.29cos(\\frac{4{\\pi}n}{N-1})-0.388cos(\\frac{6{\\pi}n}{N-1})+0.0322cos(\\frac{8{\\pi}n}{N-1}))\/4.634, n\\in[0, N-1] <\/span>\n<p><img decoding=\"async\" class=\"aligncenter size-full wp-image-921\" src=\"http:\/\/www.zptest.com\/wp-content\/uploads\/2020\/09\/flattop.png\" alt=\"\" width=\"710\" height=\"216\" \/><\/p>\n<h3>Blackman-Harris<\/h3>\n<span class=\"katex-eq\" data-katex-display=\"true\"> w(n) = 0.35875 - 0.48829cos(\\frac{2{\\pi}n}{N-1})+0.14128cos(\\frac{4{\\pi}n}{N-1})-0.01168cos(\\frac{6{\\pi}n}{N-1}) <\/span>\n<p><img decoding=\"async\" class=\"aligncenter size-full wp-image-922\" src=\"http:\/\/www.zptest.com\/wp-content\/uploads\/2020\/09\/blackharris.png\" alt=\"\" width=\"710\" height=\"216\" \/><\/p>\n<h3>Kaiser-Bessel<\/h3>\n<span class=\"katex-eq\" data-katex-display=\"true\"> w(n) = 0.40243 - 0.49804cos(\\frac{2{\\pi}n}{N-1})+0.09831cos(\\frac{4{\\pi}n}{N-1})-0.00122cos(\\frac{6{\\pi}n}{N-1}) <\/span>\n<p><img decoding=\"async\" class=\"aligncenter size-full wp-image-923\" src=\"http:\/\/www.zptest.com\/wp-content\/uploads\/2020\/09\/kaiserbessel.png\" alt=\"\" width=\"710\" height=\"216\" \/><\/p>\n<h3>\u7a97\u51fd\u6570\u7684\u5f71\u54cd<\/h3>\n<p>\u56e0\u4e3a\u52a0\u7a97\u76f8\u5f53\u4e8e\u5bf9\u88ab\u6d4b\u4fe1\u53f7\u9891\u57df\u4e0a\u7684\u5377\u79ef\uff0c\u7ed3\u679c\u76f8\u5f53\u4e8e\u5c06\u7a97\u51fd\u6570\u9891\u8c31\u5e73\u79fb\u5230\u539f\u4fe1\u53f7\u9891\u8c31\u540e\u7684\u52a0\u6743\u53e0\u52a0\uff0c\u4e5f\u5c31\u662f\u5c06\u539f\u9891\u57df\u4fe1\u53f7\u6cbf\u7740\u7a97\u51fd\u6570\u9891\u57df\u66f2\u7ebf\u6cc4\u9732\u4e86\u51fa\u53bb\uff0c\u7a97\u51fd\u6570\u7684\u4e3b\u74e3\u5bbd\u5ea6\u548c\u65c1\u74e3\u8870\u51cf\u76f4\u63a5\u5f71\u54cd\u4e86\u7a97\u51fd\u6570\u7684\u6027\u80fd\u3002<\/p>\n<p><img decoding=\"async\" class=\"aligncenter size-full wp-image-924\" src=\"http:\/\/www.zptest.com\/wp-content\/uploads\/2020\/09\/leak.png\" alt=\"\" width=\"424\" height=\"424\" \/><\/p>\n<p>\u8003\u8651\u5230\u6570\u5b57\u4fe1\u53f7\u5904\u7406\u4ec5\u8ba1\u7b97<span class=\"katex-eq\" data-katex-display=\"false\">n{\\Delta}f<\/span>\u5404\u70b9\u7684\u503c\uff0c\u56e0\u6b64\u5f53\u88ab\u6d4b\u4fe1\u53f7\u9891\u7387\u9760\u8fd1<span class=\"katex-eq\" data-katex-display=\"false\">n{\\Delta}f<\/span>\u65f6\u6cc4\u9732\u8f83\u5c0f\uff0c\u800c\u9760\u8fd1<span class=\"katex-eq\" data-katex-display=\"false\">(n + 1\/2){\\Delta}f<\/span>\u65f6\u6cc4\u9732\u8f83\u5927\u3002<\/p>\n<p>\u7a97\u51fd\u6570\u7684\u4e3b\u74e3\u5bbd\u5ea6\u8d8a\u5927\uff0c\u9891\u8c31\u7684\u5e45\u503c\u5c31\u8d8a\u63a5\u8fd1\u88ab\u6d4b\u4fe1\u53f7\uff0c\u4f46\u662f\u540c\u65f6\u8ddd\u79bb\u8f83\u8fd1\u7684\u9891\u7387\u5c31\u8d8a\u96be\u88ab\u5206\u8fa8\u51fa\u6765\u3002\u65c1\u74e3\u8870\u51cf\u7684\u8d8a\u5feb\u5219\u7531\u65c1\u74e3\u5e26\u6765\u7684\u6cc4\u9732\u4e5f\u8d8a\u5c0f\u3002<\/p>\n<h3>\u00a0\u603b\u7ed3<\/h3>\n<p>\u7a97\u51fd\u6570\u7684\u533a\u522b\u4e3b\u8981\u8003\u8651\u5176\u4e3b\u74e3\u5bbd\u5ea6\u548c\u65c1\u74e3\u8870\u51cf\u3002\u4e3b\u74e3\u7684\u9876\u90e8\u5bbd\u5ea6\u8d8a\u5bbd\uff0c\u5bf9\u5e45\u503c\u6d4b\u91cf\u7684\u7cbe\u5ea6\u8d8a\u9ad8\u3002\u4e3b\u74e3\u5bbd\u5ea6\u548c\u65c1\u74e3\u7684\u8870\u51cf\u540c\u65f6\u5f71\u54cd\u9891\u7387\u7684\u5206\u8fa8\u80fd\u529b\uff0c\u4e3b\u74e3\u5bbd\u5ea6\u8d8a\u5c0f\u3001\u65c1\u74e3\u8870\u51cf\u8d8a\u5feb\uff0c\u5bf9\u9891\u7387\u7684\u5206\u8fa8\u80fd\u529b\u8d8a\u5f3a\uff0c\u6cc4\u9732\u7684\u7a0b\u5ea6\u5c31\u8d8a\u5c0f\u3002\u5728\u4f7f\u7528\u8fc7\u7a0b\u4e2d\u5e94\u8be5\u6839\u636e\u6d4b\u8bd5\u7684\u5b9e\u9645\u60c5\u51b5\u9009\u62e9\u5408\u9002\u7a97\u51fd\u6570\u3002\u901a\u5e38\u60c5\u51b5\u4e0b\u77e9\u5f62\u7a97\u9002\u5408\u88ab\u6d4b\u4fe1\u53f7\u81ea\u8eab\u53ef\u4ee5\u4fdd\u8bc1\u6574\u5468\u671f\u91c7\u6837\u7684\u60c5\u51b5\uff0c\u5982\u529b\u9524\u6572\u51fb\u7b49\uff1b\u968f\u673a\u4fe1\u53f7\u53ef\u9009\u7528\u6c49\u5b81\u7a97\uff0c\u53ef\u4ee5\u540c\u65f6\u517c\u987e\u5e45\u503c\u7cbe\u5ea6\u548c\u5206\u8fa8\u80fd\u529b\uff1b\u5e73\u9876\u7a97\u9002\u5408\u6821\u51c6\u7b49\u5e45\u503c\u9700\u8981\u7cbe\u786e\u6d4b\u91cf\u7684\u60c5\u51b5\u3002<\/p>\n<\/div><div class=\"fusion-column-wrapper\" style=\"content:&#039;&#039;;z-index:-1;position:absolute;top:0;right:0;bottom:0;left:0;background-position:left top;background-repeat:no-repeat;-webkit-background-size:cover;-moz-background-size:cover;-o-background-size:cover;background-size:cover;\"><\/div><\/div><\/div><style type=\"text\/css\">.fusion-body .fusion-builder-column-0{width:100% !important;margin-top : 0px;margin-bottom : 0px;}.fusion-builder-column-0 > .fusion-column-wrapper {padding-top : 0px !important;padding-right : 0px !important;margin-right : 1.92%;padding-bottom : 0px !important;padding-left : 0px !important;margin-left : 1.92%;}@media only screen and (max-width:640px) {.fusion-body .fusion-builder-column-0{width:100% !important;}.fusion-builder-column-0 > .fusion-column-wrapper {margin-right : 1.92%;margin-left : 1.92%;}}@media only screen and (max-width:320px) {.fusion-body .fusion-builder-column-0{width:100% !important;}.fusion-builder-column-0 > .fusion-column-wrapper {margin-right : 1.92%;margin-left : 1.92%;}}<\/style><\/div><style type=\"text\/css\">.fusion-body .fusion-flex-container.fusion-builder-row-1{ padding-top : 0px;margin-top : 0px;padding-right : 0px;padding-bottom : 0px;margin-bottom : 0px;padding-left : 0px;}<\/style><\/div>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":5,"featured_media":2483,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[50],"tags":[],"class_list":["post-2474","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-knowledge-sharing"],"_links":{"self":[{"href":"http:\/\/www.zptest.com\/wp-json\/wp\/v2\/posts\/2474","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.zptest.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.zptest.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.zptest.com\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"http:\/\/www.zptest.com\/wp-json\/wp\/v2\/comments?post=2474"}],"version-history":[{"count":2,"href":"http:\/\/www.zptest.com\/wp-json\/wp\/v2\/posts\/2474\/revisions"}],"predecessor-version":[{"id":2484,"href":"http:\/\/www.zptest.com\/wp-json\/wp\/v2\/posts\/2474\/revisions\/2484"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.zptest.com\/wp-json\/wp\/v2\/media\/2483"}],"wp:attachment":[{"href":"http:\/\/www.zptest.com\/wp-json\/wp\/v2\/media?parent=2474"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.zptest.com\/wp-json\/wp\/v2\/categories?post=2474"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.zptest.com\/wp-json\/wp\/v2\/tags?post=2474"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}