{"id":418,"date":"2012-11-17T10:30:02","date_gmt":"2012-11-17T12:30:02","guid":{"rendered":"http:\/\/efagundes.com\/openclass_networking\/?page_id=418"},"modified":"2022-01-16T17:51:05","modified_gmt":"2022-01-16T20:51:05","slug":"tipos-de-modulacao-i","status":"publish","type":"page","link":"https:\/\/efagundes.com\/networking\/sistema-telefonico\/tipos-de-modulacao-i\/","title":{"rendered":"Tipos de modula\u00e7\u00e3o (I)"},"content":{"rendered":"<p>&nbsp;<\/p>\n<p><a href=\"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide124.jpg\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"2462\" data-permalink=\"https:\/\/efagundes.com\/networking\/sistema-telefonico\/tipos-de-modulacao-i\/slide12-5\/\" data-orig-file=\"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide124.jpg?fit=960%2C720&amp;ssl=1\" data-orig-size=\"960,720\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"Slide12\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide124.jpg?fit=960%2C720&amp;ssl=1\" class=\"alignnone size-full wp-image-2462\" src=\"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide124.jpg?resize=960%2C720\" alt=\"Slide12\" width=\"960\" height=\"720\" srcset=\"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide124.jpg?w=960&amp;ssl=1 960w, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide124.jpg?resize=300%2C225&amp;ssl=1 300w\" sizes=\"auto, (max-width: 960px) 100vw, 960px\" \/><\/a>Para facilitar a transmiss\u00e3o do sinal atrav\u00e9s dos meios f\u00edsicos e adequar as frequ\u00eancias aos sistemas de comunica\u00e7\u00e3o se utiliza o que chamamos de onda portadora, sobre a qual \u00e9 transmitido o sinal com a informa\u00e7\u00e3o.<\/p>\n<p>A onda portadora \u00e9 um sinal senoidal caracterizado por tr\u00eas vari\u00e1veis: amplitude, freq\u00fc\u00eancia e fase. A amplitude \u00e9 a medida da altura da onda para voltagem positiva ou para voltagem negativa. Tamb\u00e9m definida como crista da onda, a amplitude do sinal digital \u00e9 igual \u00e0 diferen\u00e7a da voltagem para o degrau entre 0 e 1. Iniciando na voltagem zero, a onda cresce atinge a amplitude, decresce, se anula, atinge sua amplitude negativa e volta a crescer at\u00e9 se anular novamente. Essa seq\u00fc\u00eancia comp\u00f5e um ciclo.<\/p>\n<p>Modula\u00e7\u00e3o \u00e9 o processo na qual a informa\u00e7\u00e3o \u00e9 adicionada a ondas eletromagn\u00e9ticas. \u00c9 assim que qualquer tipo de informa\u00e7\u00e3o, at\u00e9 a voz humana ou transa\u00e7\u00e3o de dados numa aplica\u00e7\u00e3o interativa \u00e9 transmitida numa onda eletromagn\u00e9tica. O transmissor adiciona a informa\u00e7\u00e3o numa onda b\u00e1sica de tal forma que poder\u00e1 ser recuperada na outra parte atrav\u00e9s de um processo reverso chamado demodula\u00e7\u00e3o.<\/p>\n<p>Nas modernas redes de telecomunica\u00e7\u00e3o, a informa\u00e7\u00e3o \u00e9 transmitida, transformando em uma das duas caracter\u00edsticas da onda: a amplitude e a freq\u00fc\u00eancia.<\/p>\n<p>Modula\u00e7\u00e3o em Amplitude &#8211; AM (Amplitude Modulation) &#8211; usa o sistema de chaveamento de amplitude ASK (Amplitude Shift Keying). \u00c9 usada na comunica\u00e7\u00e3o de voz, na maioria das transmiss\u00f5es de LAN\u2019s, mas pouco indicada para WLAN porque \u00e9 muito sens\u00edvel ao ru\u00eddo;<\/p>\n<p>Modula\u00e7\u00e3o por freq\u00fc\u00eancia &#8211; FM (Frequency Modulation) &#8211; usa o chaveamento de freq\u00fc\u00eancia FSK (Frequency Shift Keying).<\/p>\n<p>Modula\u00e7\u00e3o por fase\u00a0 &#8211;\u00a0 Na forma mais simples, a onda portadora \u00e9 deslocada de forma sistem\u00e1tica 0 ou 180 graus em intervalos uniformemente espa\u00e7ados. Um esquema melhor \u00e9 usar deslocamentos de 45, 135, 225 ou 315 graus para transmitir dois bits de informa\u00e7\u00f5es por intervalo de tempo.<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>&nbsp; Para facilitar a transmiss\u00e3o do sinal atrav\u00e9s dos meios f\u00edsicos e adequar as frequ\u00eancias aos sistemas de comunica\u00e7\u00e3o se utiliza o que chamamos de onda portadora, sobre a qual \u00e9 transmitido o sinal com a informa\u00e7\u00e3o. A onda portadora \u00e9 um sinal senoidal caracterizado por tr\u00eas vari\u00e1veis: amplitude, freq\u00fc\u00eancia e fase. A amplitude \u00e9 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":394,"menu_order":14,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-418","page","type-page","status-publish","hentry"],"jetpack_shortlink":"https:\/\/wp.me\/P8yKGp-6K","jetpack-related-posts":[{"id":420,"url":"https:\/\/efagundes.com\/networking\/sistema-telefonico\/tipos-de-modulacao-ii\/","url_meta":{"origin":418,"position":0},"title":"Tipos de modula\u00e7\u00e3o (II)","author":"Eduardo Fagundes","date":"17\/11\/2012","format":false,"excerpt":"Um baud \u00e9 um sinal ou onda el\u00e9trica anal\u00f3gica. Um ciclo de uma onda anal\u00f3gica \u00e9 igual a um baud. Um ciclo completo inicia na voltagem zero, vai at\u00e9 a mais alta voltagem e desce at\u00e9 a voltagem negativa mais baixa e volta para a voltagem zero. 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Para cada caso existem t\u00e9cnicas particulares a serem empregadas. A modula\u00e7\u00e3o constitui-se na t\u00e9cnica empregada para modificar um sinal com a finalidade de transportar uma informa\u00e7\u00e3o atrav\u00e9s do canal de comunica\u00e7\u00e3o e recuperar o sinal, na sua\u2026","rel":"","context":"Post similar","block_context":{"text":"Post similar","link":""},"img":{"alt_text":"Slide11","src":"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide117.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide117.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide117.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide117.jpg?resize=700%2C400 2x"},"classes":[]},{"id":345,"url":"https:\/\/efagundes.com\/networking\/transmissao-sem-fio\/radio-digital\/","url_meta":{"origin":418,"position":2},"title":"R\u00e1dio Digital","author":"Eduardo Fagundes","date":"16\/11\/2012","format":false,"excerpt":"\u00a0 Usa ondas eletromagn\u00e9ticas (r\u00e1dio ou infravermelho) para transmitir informa\u00e7\u00e3o de um ponto a outro, sem necessitar de alguma uma conex\u00e3o f\u00edsica. Ondas de r\u00e1dio s\u00e3o geralmente referidas como portadoras de r\u00e1dio porque simplesmente fazem a fun\u00e7\u00e3o de entregar energia para um receptor remoto. 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O m\u00e9todo pelo qual v\u00e1rios sinais em diferentes comprimentos de onda s\u00e3o combinados numa \u00fanica fibra \u00e9 conhecido pelo nome de multiplexa\u00e7\u00e3o\u2026","rel":"","context":"Post similar","block_context":{"text":"Post similar","link":""},"img":{"alt_text":"Slide30","src":"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide301.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide301.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide301.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide301.jpg?resize=700%2C400 2x"},"classes":[]},{"id":486,"url":"https:\/\/efagundes.com\/networking\/multiplexacao-2\/multiplexacao-por-divisao-de-tempo-2\/","url_meta":{"origin":418,"position":4},"title":"Multiplexa\u00e7\u00e3o por divis\u00e3o de tempo (II)","author":"Eduardo Fagundes","date":"17\/11\/2012","format":false,"excerpt":"Uma vez digitalizado, o sinal de voz tenta usar t\u00e9cnicas estat\u00edsticas para reduzir o n\u00famero de bits necess\u00e1rios por canal. Essas t\u00e9cnicas s\u00e3o apropriadas n\u00e3o apenas para codifica\u00e7\u00e3o de voz, mas tamb\u00e9m para a digitaliza\u00e7\u00e3o de qualquer sinal anal\u00f3gico. Um m\u00e9todo chamado modula\u00e7\u00e3o de c\u00f3digo de pulso diferencial (differential pulse\u2026","rel":"","context":"Post similar","block_context":{"text":"Post similar","link":""},"img":{"alt_text":"Slide5","src":"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide55.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide55.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide55.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide55.jpg?resize=700%2C400 2x"},"classes":[]},{"id":424,"url":"https:\/\/efagundes.com\/networking\/sistema-telefonico\/tipos-de-modulacao-iv\/","url_meta":{"origin":418,"position":5},"title":"Tipos de modula\u00e7\u00e3o (IV)","author":"Eduardo Fagundes","date":"17\/11\/2012","format":false,"excerpt":"\u00a0 Todos os modems avan\u00e7ados utilizam uma combina\u00e7\u00e3o de t\u00e9cnicas de modula\u00e7\u00e3o para transmitir v\u00e1rios bits por baud. Com freq\u00fc\u00eancia, v\u00e1rias amplitudes e v\u00e1rios deslocamento de fase s\u00e3o combinados para transmitir diversos bits\/s\u00edmbolos. 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