{"id":5380,"date":"2023-06-05T16:19:39","date_gmt":"2023-06-05T08:19:39","guid":{"rendered":"http:\/\/www.dcl-controls.com\/?p=5380"},"modified":"2025-03-31T09:18:37","modified_gmt":"2025-03-31T09:18:37","slug":"why-voltage-signal-oscillate","status":"publish","type":"post","link":"https:\/\/dclactuator.com\/cs_cz\/podpora\/ta-akutator\/proc-napetovy-signal-osciluje","title":{"rendered":"Pro\u010d v\u00fdstupn\u00ed sign\u00e1ly nap\u011bt\u00ed za ur\u010dit\u00fdch podm\u00ednek osciluj\u00ed?"},"content":{"rendered":"<div data-elementor-type=\"wp-post\" data-elementor-id=\"5380\" class=\"elementor elementor-5380\" data-elementor-post-type=\"post\">\n\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-1893469 elementor-section-full_width elementor-section-height-default elementor-section-height-default\" data-id=\"1893469\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-61d5be0\" data-id=\"61d5be0\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-f64e7bf elementor-widget elementor-widget-text-editor\" data-id=\"f64e7bf\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<h3>\u00a0<\/h3><h2><strong>1. Cesta p\u0159enosu nap\u011b\u0165ov\u00e9ho sign\u00e1lu<\/strong><\/h2><figure style=\"width: 960px\" class=\"wp-caption alignnone\"><img fetchpriority=\"high\" decoding=\"async\" src=\"\/wp-content\/uploads\/2023\/06\/voltage-signal-path.webp\" alt=\"Obr. 1 P\u0159enosov\u00e1 cesta sign\u00e1l\u016f zdroje nap\u011bt\u00ed\" width=\"960\" height=\"299\" \/><figcaption class=\"wp-caption-text\">Obr. 1 P\u0159enosov\u00e1 cesta sign\u00e1l\u016f zdroje nap\u011bt\u00ed<\/figcaption><\/figure><p>Jak je zn\u00e1zorn\u011bno v <strong>Obr\u00e1zek 1<\/strong>Syst\u00e9m p\u0159enosu nap\u011b\u0165ov\u00e9ho sign\u00e1lu se skl\u00e1d\u00e1 ze t\u0159\u00ed kl\u00ed\u010dov\u00fdch komponent:<\/p><ol><li><p><strong>Obvod v\u00fdstupn\u00edho nap\u011bt\u00ed z\u00e1porn\u00e9 zp\u011btn\u00e9 vazby<\/strong><\/p><\/li><li><p><strong>Kabel pro p\u0159enos sign\u00e1lu<\/strong><\/p><ul><li><p>Zahrnuje <strong>parazitn\u00ed kapacita (C1)<\/strong> a <strong>parazitn\u00ed induk\u010dnost (L1)<\/strong>, kter\u00e9 z\u00e1vis\u00ed na <strong>d\u00e9lka kabelu<\/strong> a <strong>rozlo\u017een\u00ed zapojen\u00ed<\/strong>.<\/p><\/li><\/ul><\/li><li><p><strong>Obvod pro sb\u011br vstupn\u00edho sign\u00e1lu<\/strong><\/p><ul><li><p>M\u016f\u017ee zahrnovat <strong>n\u00edzkop\u00e1smov\u00fd filtr (L2, C2)<\/strong>.<\/p><\/li><\/ul><\/li><\/ol><hr \/><h2><strong>2. Pro\u010d doch\u00e1z\u00ed k oscilaci?<\/strong><\/h2><p>V syst\u00e9mu s negativn\u00ed zp\u011btnou vazbou nap\u011b\u0165ov\u00e9ho sign\u00e1lu se vstupn\u00ed sign\u00e1l vypo\u010d\u00edt\u00e1 jako:<\/p><p><span class=\"katex\">\u2223Xi\u2032\u2223=\u2223Xi\u2223\u2212\u2223Xf\u2223|X_i&#039;| = |X_i| \u2013 |X_f|<\/span><\/p><p>Pokud v\u0161ak <strong>sign\u00e1l zp\u011btn\u00e9 vazby (|Xf|) je f\u00e1zov\u011b posunut o 180\u00b0<\/strong>, rovnice se zm\u011bn\u00ed na:<\/p><p><span class=\"katex\">\u2223Xi\u2032\u2223=\u2223Xi\u2223+\u2223Xf\u2223|X_i&#039;| = |X_i| + |X_f|<\/span><\/p><p>To znamen\u00e1, \u017ee i kdy\u017e <strong>\u017e\u00e1dn\u00fd vstupn\u00ed sign\u00e1l<\/strong> se aplikuje (<strong>|Xi| = 0<\/strong>), ten\/ta\/to <strong>zp\u011btnovazebn\u00ed sign\u00e1l udr\u017euje v\u00fdstup<\/strong>, co\u017e vede k <strong>samoudr\u017euj\u00edc\u00ed oscilace<\/strong>.<\/p><p>Aby k oscilaci do\u0161lo, mus\u00ed b\u00fdt spln\u011bny dv\u011b podm\u00ednky:<\/p><ol><li><p><strong>Zisk smy\u010dky je v\u011bt\u0161\u00ed ne\u017e 1:<\/strong> <strong>|AF| &gt; 1<\/strong><\/p><\/li><li><p><strong>F\u00e1zov\u00fd posun spl\u0148uje:<\/strong> <strong>\u03c6A + \u03c6F = (2n+1)\u03c0<\/strong><\/p><\/li><\/ol><p>Na str\u00e1nk\u00e1ch <strong>f\u00e1zov\u00fd posun<\/strong> ve smy\u010dce poch\u00e1z\u00ed z v\u00edce zdroj\u016f:<br \/>\u2714 <strong>Parazitn\u00ed kapacita (C1) a induk\u010dnost (L1) v p\u0159enosov\u00e9m kabelu<\/strong><br \/>\u2714 <strong>Sou\u010d\u00e1sti doln\u00ed propusti (L2, C2) ve vstupn\u00edm obvodu<\/strong><br \/>\u2714 <strong>Filtra\u010dn\u00ed kondenz\u00e1tory ve v\u00fdstupn\u00edm obvodu<\/strong><\/p><p>Pokud <strong>celkov\u00fd f\u00e1zov\u00fd posun dos\u00e1hne 180\u00b0<\/strong>, m\u016f\u017ee doj\u00edt k vlastn\u00edm kmit\u016fm.<\/p><hr \/><h2><strong>3. Jak zabr\u00e1nit oscilaci?<\/strong><\/h2><p>Aby se zabr\u00e1nilo kmit\u00e1n\u00ed, <strong>jedna ze dvou v\u00fd\u0161e uveden\u00fdch podm\u00ednek nesm\u00ed b\u00fdt spln\u011bna<\/strong> v r\u00e1mci provozn\u00edho frekven\u010dn\u00edho rozsahu.<\/p><figure style=\"width: 417px\" class=\"wp-caption alignnone\"><img decoding=\"async\" class=\"size-medium\" src=\"\/wp-content\/uploads\/2023\/06\/self-excited-oscilation-factor.webp\" alt=\"Obr. 2 Stav negativn\u00ed zp\u011btn\u00e9 vazby bez kmit\u00e1n\u00ed\" width=\"417\" height=\"415\" \/><figcaption class=\"wp-caption-text\">Obr. 2 Stav negativn\u00ed zp\u011btn\u00e9 vazby bez kmit\u00e1n\u00ed<\/figcaption><\/figure><p>Jak je zn\u00e1zorn\u011bno v <strong>Obr\u00e1zek 2<\/strong>, uva\u017euj\u00ed se dv\u011b kritick\u00e9 frekvence:<\/p><ul><li><p><strong>fc:<\/strong> Frekvence, kde zes\u00edlen\u00ed smy\u010dky <strong>|AF| klesne na 0 dB<\/strong>.<\/p><\/li><li><p><strong>pro:<\/strong> Frekvence, kde f\u00e1zov\u00fd posun smy\u010dky p\u0159ekra\u010duje <strong>-180\u00b0<\/strong>.<\/p><\/li><\/ul><p>Pro udr\u017een\u00ed stability, <strong>zisk by m\u011bl b\u00fdt pod 0 dB<\/strong> kdy\u017e f\u00e1zov\u00fd posun dos\u00e1hne -180\u00b0.<\/p><hr \/><h2><strong>4. Pro\u010d jsou proudov\u00e9 v\u00fdstupn\u00ed sign\u00e1ly stabiln\u011bj\u0161\u00ed<\/strong><\/h2><figure style=\"width: 600px\" class=\"wp-caption alignnone\"><img decoding=\"async\" class=\"size-medium\" src=\"\/wp-content\/uploads\/2023\/06\/current-signal-feedback-path.webp\" alt=\"Obr. 3 Zp\u011btnovazebn\u00ed smy\u010dka zdroje proudu\" width=\"600\" height=\"406\" \/><figcaption class=\"wp-caption-text\">Obr. 3 Zp\u011btnovazebn\u00ed smy\u010dka zdroje proudu<\/figcaption><\/figure><figure style=\"width: 586px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium\" src=\"\/wp-content\/uploads\/2023\/06\/voltage-signal-feedback-path.webp\" alt=\"Obr. 4 Zp\u011btnovazebn\u00ed smy\u010dka zdroje nap\u011bt\u00ed\" width=\"586\" height=\"425\" \/><figcaption class=\"wp-caption-text\">Obr. 4 Zp\u011btnovazebn\u00ed smy\u010dka zdroje nap\u011bt\u00ed<\/figcaption><\/figure><p><strong>Obvody pro v\u00fdstup proudov\u00e9ho sign\u00e1lu<\/strong> jsou m\u00e9n\u011b n\u00e1chyln\u00e9 k oscilaci, proto\u017ee:<br \/>\u2714 <strong>Jejich zp\u011btnovazebn\u00ed cesta je omezena na vnit\u0159n\u00ed komponenty<\/strong> (jak je zn\u00e1zorn\u011bno v <strong>Obr\u00e1zek 3<\/strong>).<br \/>\u2714 <strong>Kol\u00eds\u00e1n\u00ed extern\u00edho zat\u00ed\u017een\u00ed m\u00e1 mal\u00fd vliv na f\u00e1zov\u00fd posun nebo zes\u00edlen\u00ed<\/strong>.<\/p><p>Naproti tomu <strong>obvody nap\u011b\u0165ov\u00e9ho v\u00fdstupu<\/strong> (Obr\u00e1zek 4) z\u00edskat zp\u011btnou vazbu od <strong>v\u00fdstupn\u00ed bod<\/strong>, co\u017e znamen\u00e1, \u017ee <strong>extern\u00ed kabely a vzorkovac\u00ed obvody<\/strong> m\u016f\u017ee ovlivnit f\u00e1zov\u00fd posun a zes\u00edlen\u00ed. Pokud se jejich parametry zm\u011bn\u00ed, syst\u00e9m <strong>m\u016f\u017ee spl\u0148ovat podm\u00ednky oscilace<\/strong>, co\u017e vede k nestabilit\u011b.<\/p><hr \/><h3><strong>5. Z\u00e1v\u011br<\/strong><\/h3><p>V\u00fdstupn\u00ed sign\u00e1ly nap\u011b\u0165ov\u00e9ho typu mohou oscilovat, kdy\u017e:<br \/>\u2714 <strong>Parazitn\u00ed komponenty zav\u00e1d\u011bj\u00ed f\u00e1zov\u00fd posun o 180\u00b0.<\/strong><br \/>\u2714 <strong>Zisk smy\u010dky z\u016fst\u00e1v\u00e1 p\u0159i tomto f\u00e1zov\u00e9m posunu v\u011bt\u0161\u00ed ne\u017e 1.<\/strong><\/p><p>Aby se zabr\u00e1nilo oscilaci:<br \/>\u2714 <strong>Zajist\u011bte, aby zes\u00edlen\u00ed smy\u010dky bylo sn\u00ed\u017eeno pod 0 dB, ne\u017e f\u00e1zov\u00fd posun dos\u00e1hne 180\u00b0.<\/strong><br \/>\u2714 <strong>Minimalizujte parazitn\u00ed kapacitu\/induk\u010dnost v p\u0159enosov\u00fdch kabelech.<\/strong><br \/>\u2714 <strong>Pou\u017eijte vhodn\u00e9 filtrov\u00e1n\u00ed ke stabilizaci zp\u011btnovazebn\u00ed smy\u010dky.<\/strong><\/p><p>Naproti tomu <strong>proudov\u00e9 v\u00fdstupy<\/strong> jsou stabiln\u011bj\u0161\u00ed, proto\u017ee jejich <strong>zp\u011btnovazebn\u00ed smy\u010dka je m\u00e9n\u011b ovlivn\u011bna vn\u011bj\u0161\u00edmi z\u00e1t\u011b\u017eov\u00fdmi podm\u00ednkami<\/strong>.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>","protected":false},"excerpt":{"rendered":"<p>\u00a0 1. Cesta p\u0159enosu nap\u011b\u0165ov\u00e9ho sign\u00e1lu Jak je zn\u00e1zorn\u011bno na obr\u00e1zku 1, syst\u00e9m p\u0159enosu nap\u011b\u0165ov\u00e9ho sign\u00e1lu se skl\u00e1d\u00e1 ze t\u0159\u00ed kl\u00ed\u010dov\u00fdch komponent: Obvod negativn\u00ed zp\u011btn\u00e9 vazby nap\u011bt\u00ed Kabel pro p\u0159enos sign\u00e1lu Zahrnuje parazitn\u00ed kapacitu (C1) a parazitn\u00ed induk\u010dnost (L1), kter\u00e9 z\u00e1vis\u00ed na d\u00e9lce kabelu a uspo\u0159\u00e1d\u00e1n\u00ed zapojen\u00ed. Obvod pro sb\u011br vstupn\u00edho sign\u00e1lu M\u016f\u017ee zahrnovat doln\u00ed propust (L2, [\u2026]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"elementor_theme","format":"standard","meta":{"_acf_changed":true,"footnotes":""},"categories":[8],"tags":[49],"class_list":["post-5380","post","type-post","status-publish","format-standard","hentry","category-ta-acutator","tag-input-signal"],"acf":[],"_links":{"self":[{"href":"https:\/\/dclactuator.com\/cs_cz\/wp-json\/wp\/v2\/posts\/5380","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dclactuator.com\/cs_cz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dclactuator.com\/cs_cz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dclactuator.com\/cs_cz\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/dclactuator.com\/cs_cz\/wp-json\/wp\/v2\/comments?post=5380"}],"version-history":[{"count":0,"href":"https:\/\/dclactuator.com\/cs_cz\/wp-json\/wp\/v2\/posts\/5380\/revisions"}],"wp:attachment":[{"href":"https:\/\/dclactuator.com\/cs_cz\/wp-json\/wp\/v2\/media?parent=5380"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dclactuator.com\/cs_cz\/wp-json\/wp\/v2\/categories?post=5380"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dclactuator.com\/cs_cz\/wp-json\/wp\/v2\/tags?post=5380"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}