{"id":567,"date":"2010-11-02T09:26:05","date_gmt":"2010-11-02T13:26:05","guid":{"rendered":"http:\/\/embedded-lab.com\/blog\/?p=567"},"modified":"2012-07-30T09:29:32","modified_gmt":"2012-07-30T13:29:32","slug":"am-radio-transmission-using-avr","status":"publish","type":"post","link":"https:\/\/embedded-lab.com\/blog\/am-radio-transmission-using-avr\/","title":{"rendered":"AM radio transmission using AVR"},"content":{"rendered":"<p>When you think about building a radio transmitter circuit, the first thing that comes in mind is it requires too many analog components. But wait a minute, this guy demonstrates an AM transmission using a microcontroller. The interesting part is it uses a plant as an antenna for transmission. This project is based on Atmega324 microcontroller, internally clocked at 8 MHz, and it generates a modulated AM signal using internal timers and counters. It uses TC1 timer\/counter to generate a PWM signal of approximately 540 KHz. This is the carrier frequency. You know that before AM transmission, the high frequency carrier signal is modulated with a low frequency message signal. In this case, the carrier frequency is modulated by varying the duty cycle of the output PWM from 5% to 50% using TC0 timer\/counter.<\/p>\n<p style=\"text-align: center;\"><a rel=\"attachment wp-att-568\" href=\"http:\/\/embedded-lab.com\/blog\/?attachment_id=568\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-568 aligncenter\" title=\"radio_circuitry\" src=\"http:\/\/embedded-lab.com\/blog\/wp-content\/uploads\/2010\/11\/radio_circuitry.jpg\" alt=\"\" width=\"550\" height=\"368\" \/><\/a><\/p>\n<p><!--more--><br \/>\nThe modulated output from the microcontroller has square waves. A simple RLC resonant circuit can suppress the higher frequency components and change the square waves into sine waves. Now it is ready for transmission. The author tested it with a plant as an antenna, and worked well. Visit the link below to see more details about the project.<\/p>\n<table style=\"border-collapse: collapse; width: 100%;\">\n<tbody>\n<tr>\n<td><script type=\"text\/javascript\">\/\/ <![CDATA[\n   google_ad_client = \"pub-3251335376149574\"; \/* Embedded-Lab_Blog_468x15, created 10\/1\/10 *\/ google_ad_slot = \"5007918417\"; google_ad_width = 468; google_ad_height = 15;\n\/\/ ]]><\/script><br \/>\n<script src=\"http:\/\/pagead2.googlesyndication.com\/pagead\/show_ads.js\" type=\"text\/javascript\">\n<\/script><\/td>\n<td><a href=\"http:\/\/grieg.gotdns.com\/blog\/?p=312\" target=\"_blank\"><strong>Read More<\/strong><\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"<p>When you think about building a radio transmitter circuit, the first thing that comes in mind is it requires too many analog components. But wait a minute, this guy demonstrates an AM transmission using a microcontroller. The interesting part is it uses a plant as an antenna for transmission. This project is based on Atmega324 microcontroller, internally clocked at 8 MHz, and it generates a modulated AM signal using internal timers and counters. It uses TC1 timer\/counter to generate a PWM signal of approximately 540 KHz. This is the carrier frequency. You know that before AM transmission, the high frequency<\/p>\n","protected":false},"author":2,"featured_media":568,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15],"tags":[73,72,74],"class_list":["post-567","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-avr-projects","tag-am-transmission","tag-atmega324","tag-plant-antenna"],"_links":{"self":[{"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/posts\/567","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/comments?post=567"}],"version-history":[{"count":7,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/posts\/567\/revisions"}],"predecessor-version":[{"id":5842,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/posts\/567\/revisions\/5842"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/media\/568"}],"wp:attachment":[{"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/media?parent=567"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/categories?post=567"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/tags?post=567"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}