{"version":"1.0","provider_name":"ITU","provider_url":"https:\/\/www.itu.int\/hub\/zh-hans\/","author_name":"Ralf Vanalst","author_url":"https:\/\/www.itu.int\/hub\/zh-hans\/author\/ralf-vanalstitu-int\/","title":"A tutorial on frequency adaptive communication systems in the HF bands - ITU","type":"rich","width":600,"height":338,"html":"<blockquote class=\"wp-embedded-content\" data-secret=\"jNT9njANTO\"><a href=\"https:\/\/www.itu.int\/hub\/zh-hans\/publication\/r-hdb-64-2022\/\">A tutorial on frequency adaptive communication systems in the HF bands<\/a><\/blockquote><iframe sandbox=\"allow-scripts\" security=\"restricted\" src=\"https:\/\/www.itu.int\/hub\/zh-hans\/publication\/r-hdb-64-2022\/embed\/#?secret=jNT9njANTO\" width=\"600\" height=\"338\" title=\"\u300aA tutorial on frequency adaptive communication systems in the HF bands\u300b\u2014ITU\" data-secret=\"jNT9njANTO\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" class=\"wp-embedded-content\"><\/iframe><script type=\"text\/javascript\">\n\/* <![CDATA[ *\/\n\/*! This file is auto-generated *\/\n!function(d,l){\"use strict\";l.querySelector&&d.addEventListener&&\"undefined\"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!\/[^a-zA-Z0-9]\/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret=\"'+t.secret+'\"]'),o=l.querySelectorAll('blockquote[data-secret=\"'+t.secret+'\"]'),c=new RegExp(\"^https?:$\",\"i\"),i=0;i<o.length;i++)o[i].style.display=\"none\";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute(\"style\"),\"height\"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):\"link\"===t.message&&(r=new URL(s.getAttribute(\"src\")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener(\"message\",d.wp.receiveEmbedMessage,!1),l.addEventListener(\"DOMContentLoaded\",function(){for(var e,t,s=l.querySelectorAll(\"iframe.wp-embedded-content\"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute(\"data-secret\"))||(t=Math.random().toString(36).substring(2,12),e.src+=\"#?secret=\"+t,e.setAttribute(\"data-secret\",t)),e.contentWindow.postMessage({message:\"ready\",secret:t},\"*\")},!1)))}(window,document);\n\/\/# sourceURL=https:\/\/www.itu.int\/hub\/wp-includes\/js\/wp-embed.min.js\n\/* ]]> *\/\n<\/script>\n","thumbnail_url":"https:\/\/www.itu.int\/hub\/wp-content\/uploads\/sites\/4\/2022\/12\/r-hdb-64-2022-img-jpg-m.jpg","thumbnail_width":1024,"thumbnail_height":576,"description":"Frequency adaptive communication systems (also known as \u201cHF adaptive Systems\u201d) first appeared in the 1980s and have been developed because of the unique characteristics of HF communications and its increasing requirement for stable and reliable communication. This Handbook is a tutorial that explains the development and deployment of HF adaptive systems, describes the essential parts of an adaptive network, and addresses relevant regulatory and operational considerations from today."}