{"id":20621,"date":"2025-10-31T00:25:51","date_gmt":"2025-10-31T00:25:51","guid":{"rendered":"https:\/\/vibromera.eu\/glossary\/aliasing\/"},"modified":"2026-05-23T22:13:48","modified_gmt":"2026-05-23T22:13:48","slug":"aliasing","status":"publish","type":"glossary","link":"https:\/\/vibromera.eu\/fr\/glossary\/aliasing\/","title":{"rendered":"Qu&#039;est-ce que l&#039;aliasing dans l&#039;analyse des vibrations ?"},"content":{"rendered":"<h1>Comprendre l&#039;aliasing dans l&#039;analyse des vibrations<\/h1>\n\t\t<section class=\"woocommerce hestia-shop products is-shortcode\" id=\"products\" data-sorder=\"hestia_shop\" >\n\t\t\t\t\t\t<div class=\"\">\n\t\t\t\t\t\t<div class=\"hestia-shop-content\">\n\t\t\t<div class=\"row\" data-aos=\"fade-up\" >\t\t\t\t\t<div class=\"col-ms-6 col-sm-6 col-md-3 shop-item\">\n\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/fr\/product\/balanset-1\/\" class=\"woocommerce-LoopProduct-link woocommerce-loop-product__link\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"card-image\">\n\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/fr\/product\/balanset-1\/\" title=\"\u00c9quilibreuse portable et analyseur de vibrations Balanset-1A\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"230\" height=\"153\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/09\/77-e1693745667801-230x153.webp\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Balanset-1A kit complet \u00e9quilibreur portable et analyseur de vibrations\" srcset=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/09\/77-e1693745667801-230x153.webp 230w, https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/09\/77-e1693745667801-18x12.webp 18w, https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/09\/77-e1693745667801-360x240.webp 360w, https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/09\/77-e1693745667801-272x182.webp 272w\" sizes=\"auto, (max-width: 230px) 100vw, 230px\" \/>\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<div class=\"ripple-container\"><\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"content\">\n\t\t\t\t\t\t\t\t<span class=\"category\"><a href=\"https:\/\/vibromera.eu\/fr\/product-category\/devices\/\" rel=\"tag\">Dispositifs<\/a><\/span>\n\t\t\t\t\t\t\t\t<h4 class=\"card-title\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a class=\"shop-item-title-link\" href=\"https:\/\/vibromera.eu\/fr\/product\/balanset-1\/\" title=\"\u00c9quilibreuse portable et analyseur de vibrations Balanset-1A\">\u00c9quilibreur portable et analyseur de vibrations Balanset-1A<\/a>\n\n\t\t\t\t\t\t\t\t<\/h4>\n\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t<div class=\"footer\">\n\n\t\t\t\t\t\t\t\t\t<div class=\"price\"><h4><span class=\"woocommerce-Price-amount amount\"><span class=\"woocommerce-Price-currencySymbol\">\u20ac<\/span>1,975.00<\/span> + TVA (le cas \u00e9ch\u00e9ant)<\/h4><\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"stats\">\n\t\t\t\t\t\t\t\t\t\t<a rel=\"nofollow\" href=\"\/fr\/wp-json\/wp\/v2\/glossary\/20621?add-to-cart=986\" data-quantity=\"1\" data-product_id=\"986\" data-product_sku=\"BS-1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart btn btn-just-icon btn-simple btn-default\" title=\"Ajouter au panier\" data-no-translation-title=\"\"><i rel=\"tooltip\" data-original-title=\"Ajouter au panier\" class=\"fas fa-cart-plus\" data-no-translation-data-original-title=\"\"><\/i><\/a>\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/a><a href=\"\/fr\/wp-json\/wp\/v2\/glossary\/20621?add-to-cart=986\" aria-describedby=\"woocommerce_loop_add_to_cart_link_describedby_986\" data-quantity=\"1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart\" data-product_id=\"986\" data-product_sku=\"BS-1\" aria-label=\"Ajouter au panier\u00a0: \u201cPortable balancer &amp; Vibration analyzer Balanset-1A\u201d\" rel=\"nofollow\" data-success_message=\"\u00ab\u00a0Portable balancer &amp; Vibration analyzer Balanset-1A\u00a0\u00bb a \u00e9t\u00e9 ajout\u00e9 \u00e0 votre panier\" data-no-translation=\"\" data-trp-gettext=\"\" data-no-translation-aria-label=\"\" data-no-translation-data-success_message=\"\">Ajouter au panier<\/a>\t<span id=\"woocommerce_loop_add_to_cart_link_describedby_986\" class=\"screen-reader-text\">\n\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t<div class=\"col-ms-6 col-sm-6 col-md-3 shop-item\">\n\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/fr\/product\/vibration-sensor\/\" class=\"woocommerce-LoopProduct-link woocommerce-loop-product__link\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"card-image\">\n\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/fr\/product\/vibration-sensor\/\" title=\"Capteur de vibrations\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"230\" height=\"153\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-230x153.webp\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Gros plan du capteur de vibrations Balanset-1A\" srcset=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-230x153.webp 230w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-600x400.webp 600w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-300x200.webp 300w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-768x512.webp 768w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-1024x682.webp 1024w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-272x182.webp 272w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3.webp 1280w\" sizes=\"auto, (max-width: 230px) 100vw, 230px\" \/>\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<div class=\"ripple-container\"><\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"content\">\n\t\t\t\t\t\t\t\t<span class=\"category\"><a href=\"https:\/\/vibromera.eu\/fr\/product-category\/parts\/\" rel=\"tag\">Pi\u00e8ces d\u00e9tach\u00e9es<\/a><\/span>\n\t\t\t\t\t\t\t\t<h4 class=\"card-title\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a class=\"shop-item-title-link\" href=\"https:\/\/vibromera.eu\/fr\/product\/vibration-sensor\/\" title=\"Capteur de vibrations\">Capteur de vibrations<\/a>\n\n\t\t\t\t\t\t\t\t<\/h4>\n\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t<div class=\"footer\">\n\n\t\t\t\t\t\t\t\t\t<div class=\"price\"><h4><span class=\"woocommerce-Price-amount amount\"><span class=\"woocommerce-Price-currencySymbol\">\u20ac<\/span>90.00<\/span> + TVA (le cas \u00e9ch\u00e9ant)<\/h4><\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"stats\">\n\t\t\t\t\t\t\t\t\t\t<a rel=\"nofollow\" href=\"\/fr\/wp-json\/wp\/v2\/glossary\/20621?add-to-cart=1820\" data-quantity=\"1\" data-product_id=\"1820\" data-product_sku=\"VS-1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart btn btn-just-icon btn-simple btn-default\" title=\"Ajouter au panier\" data-no-translation-title=\"\"><i rel=\"tooltip\" data-original-title=\"Ajouter au panier\" class=\"fas fa-cart-plus\" data-no-translation-data-original-title=\"\"><\/i><\/a>\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/a><a href=\"\/fr\/wp-json\/wp\/v2\/glossary\/20621?add-to-cart=1820\" aria-describedby=\"woocommerce_loop_add_to_cart_link_describedby_1820\" data-quantity=\"1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart\" data-product_id=\"1820\" data-product_sku=\"VS-1\" aria-label=\"Ajouter au panier\u00a0: \u201cVibration sensor\u201d\" rel=\"nofollow\" data-success_message=\"\u00ab\u00a0Vibration sensor\u00a0\u00bb a \u00e9t\u00e9 ajout\u00e9 \u00e0 votre panier\" data-no-translation=\"\" data-trp-gettext=\"\" data-no-translation-aria-label=\"\" data-no-translation-data-success_message=\"\">Ajouter au panier<\/a>\t<span id=\"woocommerce_loop_add_to_cart_link_describedby_1820\" class=\"screen-reader-text\">\n\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t<div class=\"col-ms-6 col-sm-6 col-md-3 shop-item\">\n\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/fr\/product\/optical-sensor-for-balanset-and-arbalance\/\" class=\"woocommerce-LoopProduct-link woocommerce-loop-product__link\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"card-image\">\n\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/fr\/product\/optical-sensor-for-balanset-and-arbalance\/\" title=\"Capteur optique (tachym\u00e8tre laser)\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"230\" height=\"153\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-230x153.webp\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Capteur optique (tachym\u00e8tre laser)\" srcset=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-230x153.webp 230w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-300x200.webp 300w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-1024x682.webp 1024w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-768x512.webp 768w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-1536x1023.webp 1536w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-18x12.webp 18w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-360x240.webp 360w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-460x306.webp 460w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-600x400.webp 600w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-272x182.webp 272w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU.webp 1600w\" sizes=\"auto, (max-width: 230px) 100vw, 230px\" \/>\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<div class=\"ripple-container\"><\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"content\">\n\t\t\t\t\t\t\t\t<span class=\"category\"><a href=\"https:\/\/vibromera.eu\/fr\/product-category\/parts\/\" rel=\"tag\">Pi\u00e8ces d\u00e9tach\u00e9es<\/a><\/span>\n\t\t\t\t\t\t\t\t<h4 class=\"card-title\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a class=\"shop-item-title-link\" href=\"https:\/\/vibromera.eu\/fr\/product\/optical-sensor-for-balanset-and-arbalance\/\" title=\"Capteur optique (tachym\u00e8tre laser)\">Capteur optique (tachym\u00e8tre laser)<\/a>\n\n\t\t\t\t\t\t\t\t<\/h4>\n\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t<div class=\"footer\">\n\n\t\t\t\t\t\t\t\t\t<div class=\"price\"><h4><span class=\"woocommerce-Price-amount amount\"><span class=\"woocommerce-Price-currencySymbol\">\u20ac<\/span>124.00<\/span> + TVA (le cas \u00e9ch\u00e9ant)<\/h4><\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"stats\">\n\t\t\t\t\t\t\t\t\t\t<a rel=\"nofollow\" href=\"\/fr\/wp-json\/wp\/v2\/glossary\/20621?add-to-cart=1832\" data-quantity=\"1\" data-product_id=\"1832\" data-product_sku=\"Tach-1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart btn btn-just-icon btn-simple btn-default\" title=\"Ajouter au panier\" data-no-translation-title=\"\"><i rel=\"tooltip\" data-original-title=\"Ajouter au panier\" class=\"fas fa-cart-plus\" data-no-translation-data-original-title=\"\"><\/i><\/a>\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/a><a href=\"\/fr\/wp-json\/wp\/v2\/glossary\/20621?add-to-cart=1832\" aria-describedby=\"woocommerce_loop_add_to_cart_link_describedby_1832\" data-quantity=\"1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart\" data-product_id=\"1832\" data-product_sku=\"Tach-1\" aria-label=\"Ajouter au panier\u00a0: \u201cOptical Sensor (Laser Tachometer)\u201d\" rel=\"nofollow\" data-success_message=\"\u00ab\u00a0Optical Sensor (Laser Tachometer)\u00a0\u00bb a \u00e9t\u00e9 ajout\u00e9 \u00e0 votre panier\" data-no-translation=\"\" data-trp-gettext=\"\" data-no-translation-aria-label=\"\" data-no-translation-data-success_message=\"\">Ajouter au panier<\/a>\t<span id=\"woocommerce_loop_add_to_cart_link_describedby_1832\" class=\"screen-reader-text\">\n\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t<div class=\"col-ms-6 col-sm-6 col-md-3 shop-item\">\n\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/fr\/product\/balanset-4\/\" class=\"woocommerce-LoopProduct-link woocommerce-loop-product__link\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"card-image\">\n\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/fr\/product\/balanset-4\/\" title=\"Balanset-4\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"230\" height=\"153\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-230x153.webp\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Kit d&#039;\u00e9quilibrage de rotor Vibromera\u00a0: mallette de transport, conditionneur de signal multicanal, analyseur portable, base magn\u00e9tique, capteurs de vibrations et c\u00e2bles enroul\u00e9s.\" srcset=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-230x153.webp 230w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-300x200.webp 300w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-18x12.webp 18w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-360x240.webp 360w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-460x306.webp 460w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-600x400.webp 600w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-272x182.webp 272w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4.webp 640w\" sizes=\"auto, (max-width: 230px) 100vw, 230px\" \/>\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<div class=\"ripple-container\"><\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"content\">\n\t\t\t\t\t\t\t\t<span class=\"category\"><a href=\"https:\/\/vibromera.eu\/fr\/product-category\/devices\/\" rel=\"tag\">Dispositifs<\/a><\/span>\n\t\t\t\t\t\t\t\t<h4 class=\"card-title\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a class=\"shop-item-title-link\" href=\"https:\/\/vibromera.eu\/fr\/product\/balanset-4\/\" title=\"Balanset-4\">Balanset-4<\/a>\n\n\t\t\t\t\t\t\t\t<\/h4>\n\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t<div class=\"footer\">\n\n\t\t\t\t\t\t\t\t\t<div class=\"price\"><h4><span class=\"woocommerce-Price-amount amount\"><span class=\"woocommerce-Price-currencySymbol\">\u20ac<\/span>6,803.00<\/span> + TVA (le cas \u00e9ch\u00e9ant)<\/h4><\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"stats\">\n\t\t\t\t\t\t\t\t\t\t<a rel=\"nofollow\" href=\"\/fr\/wp-json\/wp\/v2\/glossary\/20621?add-to-cart=1833\" data-quantity=\"1\" data-product_id=\"1833\" data-product_sku=\"BS-4\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart btn btn-just-icon btn-simple btn-default\" title=\"Ajouter au panier\" data-no-translation-title=\"\"><i rel=\"tooltip\" data-original-title=\"Ajouter au panier\" class=\"fas fa-cart-plus\" data-no-translation-data-original-title=\"\"><\/i><\/a>\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/a><a href=\"\/fr\/wp-json\/wp\/v2\/glossary\/20621?add-to-cart=1833\" aria-describedby=\"woocommerce_loop_add_to_cart_link_describedby_1833\" data-quantity=\"1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart\" data-product_id=\"1833\" data-product_sku=\"BS-4\" aria-label=\"Ajouter au panier\u00a0: \u201cBalanset-4\u201d\" rel=\"nofollow\" data-success_message=\"\u00ab\u00a0Balanset-4\u00a0\u00bb a \u00e9t\u00e9 ajout\u00e9 \u00e0 votre panier\" data-no-translation=\"\" data-trp-gettext=\"\" data-no-translation-aria-label=\"\" data-no-translation-data-success_message=\"\">Ajouter au panier<\/a>\t<span id=\"woocommerce_loop_add_to_cart_link_describedby_1833\" class=\"screen-reader-text\">\n\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div><!-- \/.row --><div class=\"row\">\t\t\t\t\t<div class=\"col-ms-6 col-sm-6 col-md-3 shop-item\">\n\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/fr\/product\/magnet-stand\/\" class=\"woocommerce-LoopProduct-link woocommerce-loop-product__link\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"card-image\">\n\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/fr\/product\/magnet-stand\/\" title=\"Support magn\u00e9tique Insize - 60 kgf\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"230\" height=\"153\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-230x153.webp\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Base magn\u00e9tique.\" srcset=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-230x153.webp 230w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-600x400.webp 600w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-300x200.webp 300w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-1024x682.webp 1024w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-768x512.webp 768w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-360x240.webp 360w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-272x182.webp 272w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36.webp 1280w\" sizes=\"auto, (max-width: 230px) 100vw, 230px\" \/>\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<div class=\"ripple-container\"><\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"content\">\n\t\t\t\t\t\t\t\t<span class=\"category\"><a href=\"https:\/\/vibromera.eu\/fr\/product-category\/parts\/\" rel=\"tag\">Pi\u00e8ces 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product_type_simple add_to_cart_button ajax_add_to_cart\" data-product_id=\"2329\" data-product_sku=\"rt-1\" aria-label=\"Ajouter au panier\u00a0: \u201cReflective tape\u201d\" rel=\"nofollow\" data-success_message=\"\u00ab\u00a0Reflective tape\u00a0\u00bb a \u00e9t\u00e9 ajout\u00e9 \u00e0 votre panier\" data-no-translation=\"\" data-trp-gettext=\"\" data-no-translation-aria-label=\"\" data-no-translation-data-success_message=\"\">Ajouter au panier<\/a>\t<span id=\"woocommerce_loop_add_to_cart_link_describedby_2329\" class=\"screen-reader-text\">\n\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t<div class=\"col-ms-6 col-sm-6 col-md-3 shop-item\">\n\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/fr\/product\/dynamic-balancer-balanset-1a\/\" class=\"woocommerce-LoopProduct-link woocommerce-loop-product__link\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"card-image\">\n\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/fr\/product\/dynamic-balancer-balanset-1a\/\" title=\"\u00c9quilibreur dynamique &quot;Balanset-1A&quot; OEM\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"230\" height=\"153\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-230x153.webp\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Kit Balanset-1A comprenant l&#039;unit\u00e9 d&#039;interface, les capteurs, le tachym\u00e8tre et les accessoires\" srcset=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-230x153.webp 230w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-600x400.webp 600w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-300x200.webp 300w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-1024x683.webp 1024w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-768x512.webp 768w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-1536x1024.webp 1536w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-2048x1366.webp 2048w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-360x240.webp 360w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-272x182.webp 272w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-e1732998877834.webp 708w\" sizes=\"auto, (max-width: 230px) 100vw, 230px\" \/>\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<div class=\"ripple-container\"><\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"content\">\n\t\t\t\t\t\t\t\t<span class=\"category\"><a href=\"https:\/\/vibromera.eu\/fr\/product-category\/devices\/\" rel=\"tag\">Dispositifs<\/a><\/span>\n\t\t\t\t\t\t\t\t<h4 class=\"card-title\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a class=\"shop-item-title-link\" href=\"https:\/\/vibromera.eu\/fr\/product\/dynamic-balancer-balanset-1a\/\" title=\"\u00c9quilibreur dynamique &quot;Balanset-1A&quot; OEM\">\u00c9quilibreur dynamique \"Balanset-1A\" OEM<\/a>\n\n\t\t\t\t\t\t\t\t<\/h4>\n\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t<div class=\"footer\">\n\n\t\t\t\t\t\t\t\t\t<div class=\"price\"><h4><span class=\"woocommerce-Price-amount amount\"><span class=\"woocommerce-Price-currencySymbol\">\u20ac<\/span>1,735.00<\/span> + TVA (le cas \u00e9ch\u00e9ant)<\/h4><\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"stats\">\n\t\t\t\t\t\t\t\t\t\t<a rel=\"nofollow\" href=\"\/fr\/wp-json\/wp\/v2\/glossary\/20621?add-to-cart=4193\" data-quantity=\"1\" data-product_id=\"4193\" data-product_sku=\"BS-1OEM\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart btn btn-just-icon btn-simple btn-default\" title=\"Ajouter au panier\" data-no-translation-title=\"\"><i rel=\"tooltip\" data-original-title=\"Ajouter au panier\" class=\"fas fa-cart-plus\" data-no-translation-data-original-title=\"\"><\/i><\/a>\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/a><a href=\"\/fr\/wp-json\/wp\/v2\/glossary\/20621?add-to-cart=4193\" aria-describedby=\"woocommerce_loop_add_to_cart_link_describedby_4193\" data-quantity=\"1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart\" data-product_id=\"4193\" data-product_sku=\"BS-1OEM\" aria-label=\"Ajouter au panier\u00a0: \u201cDynamic balancer \u201cBalanset-1A\u201d OEM\u201d\" rel=\"nofollow\" data-success_message=\"\u00ab\u00a0Dynamic balancer \u201cBalanset-1A\u201d OEM\u00a0\u00bb a \u00e9t\u00e9 ajout\u00e9 \u00e0 votre panier\" data-no-translation=\"\" data-trp-gettext=\"\" data-no-translation-aria-label=\"\" data-no-translation-data-success_message=\"\">Ajouter au panier<\/a>\t<span id=\"woocommerce_loop_add_to_cart_link_describedby_4193\" class=\"screen-reader-text\">\n\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/section>\n\t\t\n<p><strong>Repliement de spectre<\/strong> Il s&#x27;agit d&#x27;une erreur de traitement du signal susceptible de fausser l&#x27;analyse num\u00e9rique des donn\u00e9es vibratoires. Elle survient lorsqu&#x27;un signal est \u00e9chantillonn\u00e9 \u00e0 une fr\u00e9quence trop faible pour capturer ses composantes de plus haute fr\u00e9quence, de sorte que ces hautes fr\u00e9quences \u00ab se replient \u00bb et se font passer pour des fr\u00e9quences plus basses dans le r\u00e9sultat <a href=\"https:\/\/vibromera.eu\/fr\/glossary\/fft\/\">FFT<\/a> spectre. Il en r\u00e9sulte de faux pics qui n&#x27;ont jamais exist\u00e9 dans la machine r\u00e9elle \u2014 des pics susceptibles d&#x27;entra\u00eener une grave erreur de diagnostic. Comprendre le ph\u00e9nom\u00e8ne d&#x27;aliasing et les mesures de protection qui permettent de l&#x27;\u00e9viter est essentiel pour pouvoir se fier \u00e0 tout syst\u00e8me num\u00e9rique <a href=\"https:\/\/vibromera.eu\/fr\/glossary\/spectrum\/\">spectre de vibrations<\/a>.<\/p>\n<h2>1. D\u00e9finition : qu&#x27;est-ce que l&#x27;aliasing ?<\/h2>\n<p>Lorsqu&#x27;un analyseur num\u00e9rise un signal vibratoire, il n&#x27;enregistre pas une courbe continue, mais une s\u00e9quence d&#x27;\u00e9chantillons discrets \u2014 des instantan\u00e9s pris \u00e0 intervalles r\u00e9guliers. Si ces instantan\u00e9s sont trop espac\u00e9s par rapport \u00e0 la vitesse \u00e0 laquelle le signal varie, l&#x27;analyseur est litt\u00e9ralement incapable de distinguer une onde rapide d&#x27;une onde lente. Les quelques points qu&#x27;il capte d&#x27;une composante \u00e0 haute fr\u00e9quence peuvent \u00eatre assembl\u00e9s pour former une onde sinuso\u00efdale \u00e0 basse fr\u00e9quence tout \u00e0 fait plausible. Cette basse fr\u00e9quence fant\u00f4me est la <em>alias<\/em>, et d\u00e8s qu&#x27;il appara\u00eet dans le <a href=\"https:\/\/vibromera.eu\/fr\/glossary\/spectral-analysis\/\">spectre<\/a> elle est impossible \u00e0 distinguer d&#x27;une v\u00e9ritable vibration \u00e0 cette fr\u00e9quence.<\/p>\n<h2>2. Le th\u00e9or\u00e8me de Nyquist et la fr\u00e9quence d&#x27;\u00e9chantillonnage<\/h2>\n<p>Pour comprendre l&#x27;aliasing, il faut d&#x27;abord comprendre le <strong>Th\u00e9or\u00e8me de Nyquist<\/strong> (le th\u00e9or\u00e8me d&#x27;\u00e9chantillonnage de Nyquist-Shannon). Ce principe fondamental du traitement num\u00e9rique du signal stipule que :<\/p>\n<blockquote><p>\n    <em>Pour repr\u00e9senter fid\u00e8lement un signal analogique sous forme num\u00e9rique, la fr\u00e9quence d&#x27;\u00e9chantillonnage (F<sub>s<\/sub>) doit \u00eatre au moins deux fois sup\u00e9rieure \u00e0 la composante de fr\u00e9quence la plus \u00e9lev\u00e9e (F<sub>max<\/sub>) pr\u00e9sentes dans le signal.<\/em>\n<\/p><\/blockquote>\n<p>Cette fr\u00e9quence d&#x27;\u00e9chantillonnage minimale (2 \u00d7 F<sub>max<\/sub>) est appel\u00e9e <strong>taux de Nyquist<\/strong>. En d&#x27;autres termes, la fr\u00e9quence maximale qu&#x27;un taux d&#x27;\u00e9chantillonnage donn\u00e9 peut mesurer fid\u00e8lement correspond \u00e0 la moiti\u00e9 de ce taux : F<sub>max<\/sub> = F<sub>s<\/sub> \/ 2. Ce plafond correspond \u00e0 <strong>fr\u00e9quence de Nyquist<\/strong>. Toute fr\u00e9quence r\u00e9elle sup\u00e9rieure \u00e0 la fr\u00e9quence de Nyquist ne peut \u00eatre repr\u00e9sent\u00e9e fid\u00e8lement et sera donc renvoy\u00e9e en dessous de cette fr\u00e9quence. En pratique, la fr\u00e9quence F choisie<sub>max<\/sub> d\u00e9finit \u00e9galement la r\u00e9solution de l&#x27;analyse ainsi que le nombre de lignes de la FFT \u2014 une relation que vous pouvez explorer \u00e0 l&#x27;aide d&#x27;un <a href=\"https:\/\/vibromera.eu\/fr\/calculators\/fft-resolution-calculator\/\">Calculateur de r\u00e9solution FFT<\/a> lors de la planification d&#x27;une mesure.<\/p>\n<h2>3. Comment se produit l&#x27;aliasing ?<\/h2>\n<p>Imaginez une vibration \u00e0 haute fr\u00e9quence mesur\u00e9e par un analyseur num\u00e9rique qui pr\u00e9l\u00e8ve des \u00e9chantillons discrets \u00e0 une fr\u00e9quence fixe :<\/p>\n<ul>\n<li>Si la fr\u00e9quence d&#x27;\u00e9chantillonnage est suffisamment \u00e9lev\u00e9e \u2014 bien sup\u00e9rieure \u00e0 la fr\u00e9quence de Nyquist \u2014, l&#x27;analyseur enregistre suffisamment de points par cycle pour reconstituer la forme d&#x27;onde avec pr\u00e9cision.<\/li>\n<li>Si la fr\u00e9quence d&#x27;\u00e9chantillonnage est trop faible, l&#x27;analyseur ne d\u00e9tecte pas ce qui se passe entre les \u00e9chantillons. Les quelques points qu&#x27;il parvient \u00e0 capturer s&#x27;assemblent pour former une onde sinuso\u00efdale compl\u00e8tement diff\u00e9rente, de fr\u00e9quence plus basse. Cette fausse basse fr\u00e9quence est l&#x27;alias.<\/li>\n<\/ul>\n<p>Prenons un exemple concret : supposons qu&#x27;un signal contienne une composante r\u00e9elle de 900 Hz, mais que la fr\u00e9quence F<sub>max<\/sub> est r\u00e9gl\u00e9 sur 500 Hz, ce qui correspond \u00e0 une fr\u00e9quence d&#x27;\u00e9chantillonnage de 1 000 Hz. La composante \u00e0 900 Hz se situe au-dessus de la fr\u00e9quence de Nyquist de 500 Hz et ne peut donc pas \u00eatre mesur\u00e9e correctement. Elle subit un effet d&#x27;aliasing et r\u00e9appara\u00eet \u00e0 la fr\u00e9quence F<sub>s<\/sub> \u2212 900 = 1000 \u2212 900 = 100 Hz. Un analyste examinant le spectre pourrait facilement confondre ce pic de 100 Hz avec un <a href=\"https:\/\/vibromera.eu\/fr\/glossary\/running-speed\/\">1\u00d7 vitesse de fonctionnement<\/a> une vibration, ou un v\u00e9ritable d\u00e9faut, et se mettre \u00e0 rechercher un probl\u00e8me qui n&#x27;existe pas. Pire encore, les sources de signaux \u00e0 haute fr\u00e9quence \u2014 chocs au niveau des roulements, \u00e9nergie g\u00e9n\u00e9r\u00e9e par l&#x27;engr\u00e8nement des engrenages, bruit \u00e9lectrique \u2014 sont souvent pr\u00e9cis\u00e9ment les signaux auxquels un analyste souhaite le plus se fier.<\/p>\n<h2>4. Pr\u00e9venir l&#x27;aliasing : le filtre d&#x27;anti-aliasing<\/h2>\n<p>Il est impossible de pr\u00e9voir \u00e0 l&#x27;avance l&#x27;ensemble des composantes \u00e0 haute fr\u00e9quence qu&#x27;un signal peut contenir : bruits ultrasoniques, chocs violents, interf\u00e9rences radio\u00e9lectriques et captation de signaux \u00e9lectriques peuvent tous venir perturber le signal. Se contenter d&#x27;esp\u00e9rer que la fr\u00e9quence d&#x27;\u00e9chantillonnage soit suffisamment \u00e9lev\u00e9e n&#x27;est donc pas une strat\u00e9gie fiable.<\/p>\n<p>La solution utilis\u00e9e dans tous les analyseurs de vibrations num\u00e9riques modernes est la <strong>filtre anti-aliasing<\/strong>: \u00e0 pente raide <a href=\"https:\/\/vibromera.eu\/fr\/glossary\/low-pass-filter\/\">filtre passe-bas<\/a> plac\u00e9 dans le circuit de signal <em>avant<\/em> le convertisseur analogique-num\u00e9rique (CAN). Voici comment cela fonctionne :<\/p>\n<ol>\n<li>L&#x27;utilisateur d\u00e9finit la fr\u00e9quence maximale souhait\u00e9e, F<sub>max<\/sub>, pour l&#x27;analyse.<\/li>\n<li>Sur la base de cette F<sub>max<\/sub>, l&#x27;analyseur r\u00e8gle automatiquement la fr\u00e9quence de coupure du filtre anti-aliasing juste au-dessus de F<sub>max<\/sub>.<\/li>\n<li>L&#x27;analogique <a href=\"https:\/\/vibromera.eu\/fr\/glossary\/transducer\/\">capteur<\/a> Le signal traverse le filtre, qui \u00e9limine ou att\u00e9nue fortement toutes les fr\u00e9quences sup\u00e9rieures \u00e0 la fr\u00e9quence de coupure.<\/li>\n<li>Seul le signal filtr\u00e9 et \u00e9pur\u00e9 est transmis au convertisseur analogique-num\u00e9rique (CAN) pour \u00eatre \u00e9chantillonn\u00e9.<\/li>\n<\/ol>\n<p>Parce que le filtre \u00e9limine, avant que l&#x27;\u00e9chantillonnage ait lieu, les hautes fr\u00e9quences que la fr\u00e9quence d&#x27;\u00e9chantillonnage choisie ne pourrait pas traiter <em>avant<\/em> , il rend l&#x27;aliasing physiquement impossible. Un filtre r\u00e9el ne peut pas couper de mani\u00e8re infiniment nette, c&#x27;est pourquoi la coupure est r\u00e9gl\u00e9e l\u00e9g\u00e8rement en dessous de la fr\u00e9quence de Nyquist afin de laisser une bande de garde sur sa pente. Le filtre anti-aliasing est l&#x27;un des \u00e9l\u00e9ments les plus critiques de tout analyseur, garantissant que la FFT obtenue est une image fid\u00e8le et exacte des vibrations de la machine dans la plage s\u00e9lectionn\u00e9e. Notez que ce filtrage doit \u00eatre analogique et doit pr\u00e9c\u00e9der la num\u00e9risation \u2014 l&#x27;application <a href=\"https:\/\/vibromera.eu\/fr\/glossary\/signal-filtering\/\">filtrage num\u00e9rique<\/a> Une fois que l&#x27;ADC a effectu\u00e9 la conversion, il est impossible d&#x27;annuler l&#x27;alias, car la fausse fr\u00e9quence est alors d\u00e9j\u00e0 enregistr\u00e9e dans les donn\u00e9es.<\/p>\n<h2>5. Implications pratiques pour l&#x27;analyste<\/h2>\n<p>Pour l&#x27;ing\u00e9nieur sur le terrain, la le\u00e7on \u00e0 retenir est de respecter les r\u00e9glages de fr\u00e9quence de l&#x27;appareil. Choisir F<sub>max<\/sub> trop faible pour conserver une bonne <a href=\"https:\/\/vibromera.eu\/fr\/glossary\/spectral-leakage\/\">r\u00e9solution<\/a> les pics de bas ordre peuvent masquer des informations importantes dans les hautes fr\u00e9quences ; le filtre anti-aliasing vous prot\u00e8ge contre les faux pics, mais il ne peut pas vous montrer l&#x27;\u00e9nergie que vous avez filtr\u00e9e. Les instruments fiables g\u00e8rent cela automatiquement \u2014 un analyseur portable tel que le <a href=\"https:\/\/vibromera.eu\/fr\/produit\/balanset-1\/\">Balanset-1A<\/a> applique une protection anti-aliasing mat\u00e9rielle en amont de son convertisseur analogique-num\u00e9rique (ADC) ; ainsi, les spectres qu&#x27;il fournit \u00e0 des fins de diagnostic et les donn\u00e9es d&#x27;amplitude et de phase 1\u00d7 qu&#x27;il utilise pour l&#x27;\u00e9quilibrage sont exempts d&#x27;artefacts d&#x27;aliasing sur toute sa plage de fonctionnement. Conclusions pratiques : r\u00e9gler F<sub>max<\/sub> suffisamment \u00e9lev\u00e9e pour couvrir la fr\u00e9quence de d\u00e9faut la plus \u00e9lev\u00e9e qui vous int\u00e9resse, soyez assur\u00e9 qu&#x27;un analyseur correctement con\u00e7u ne produira pas d&#x27;effet d&#x27;aliasing, et consid\u00e9rez tout pic inexpliqu\u00e9 \u00e0 basse fr\u00e9quence avec une saine m\u00e9fiance jusqu&#x27;\u00e0 ce que vous ayez \u00e9cart\u00e9 toute autre cause.<\/p>\n<hr>\n<p><a href=\"https:\/\/vibromera.eu\/fr\/glossary\/\">\u2190 Retour \u00e0 l&#039;index principal<\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>D\u00e9couvrez l&#039;aliasing, une erreur de traitement du signal dans l&#039;analyse des vibrations num\u00e9riques qui se produit lorsque le taux d&#039;\u00e9chantillonnage est trop faible, ce qui fait que les hautes fr\u00e9quences imitent les basses fr\u00e9quences.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[114,109],"tags":[],"class_list":["post-20621","glossary","type-glossary","status-publish","hentry","category-analysis","category-glossary"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/glossary\/20621","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/glossary"}],"about":[{"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/types\/glossary"}],"version-history":[{"count":1,"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/glossary\/20621\/revisions"}],"predecessor-version":[{"id":101190,"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/glossary\/20621\/revisions\/101190"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/media?parent=20621"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/categories?post=20621"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/tags?post=20621"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}