{"id":2298,"date":"2025-12-05T15:49:21","date_gmt":"2025-12-05T14:49:21","guid":{"rendered":"https:\/\/localdab.org\/?page_id=2298"},"modified":"2025-12-05T15:52:42","modified_gmt":"2025-12-05T14:52:42","slug":"dab-time-structure","status":"publish","type":"page","link":"https:\/\/localdab.org\/index.php\/glossary\/a-d\/dab-time-structure\/","title":{"rendered":"DAB Time Structure"},"content":{"rendered":"\n<p class=\"has-small-font-size wp-block-paragraph\">For <strong>DAB Mode I<\/strong>, the time structure is derived from the <strong>2048 kHz<\/strong> clock reference, corresponding to a DAB clock period of 1\/2048 kHz = <strong>488.28125 ns<\/strong>.<br>In some DAB literature, this value is also written as 0.48828125 \u00b5s, sometimes with fewer decimal places, but the value above\u2014with eight digits after the decimal point in \u00b5s\u2014is 100% correct.<br><br><em>(It is not an irrational number; its decimals do not continue indefinitely. But exactly ending in 5)<\/em><\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">In the transmitter, an oscillator running at eight times this frequency (16.384 MHz) is used, and its output is divided by 8 to obtain the required time period T = 488.28125 ns. The oscillator is synchronised to the 10 MHz time base provided by the atomic clocks in the GPS satellite constellation.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-small-font-size\">1 ms corresponds to 2048 ticks (orthogonal symbol),<\/li>\n\n\n\n<li class=\"has-small-font-size\">24 ms corresponds to 49,152 ticks (audio frames, CIF frame, ETI frame)<\/li>\n\n\n\n<li class=\"has-small-font-size\">96 ms corresponds to 196,608 ticks of this clock (transmission frame).<\/li>\n<\/ul>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">The main <strong>16.384 MHz<\/strong> oscillator has a period of approximately <strong>61 ns<\/strong>, and these ticks are used to determine the value of the TIST field in the ETI frame.<\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">The complete time structure is illustrated in the diagram below.<\/p>\n\n\n\n<figure data-wp-context=\"{&quot;imageId&quot;:&quot;6a3bd7d789816&quot;}\" data-wp-interactive=\"core\/image\" data-wp-key=\"6a3bd7d789816\" class=\"wp-block-image size-large wp-lightbox-container\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" data-wp-class--hide=\"state.isContentHidden\" data-wp-class--show=\"state.isContentVisible\" data-wp-init=\"callbacks.setButtonStyles\" data-wp-on--click=\"actions.showLightbox\" data-wp-on--load=\"callbacks.setButtonStyles\" data-wp-on--pointerdown=\"actions.preloadImage\" data-wp-on--pointerenter=\"actions.preloadImageWithDelay\" data-wp-on--pointerleave=\"actions.cancelPreload\" data-wp-on-window--resize=\"callbacks.setButtonStyles\" src=\"https:\/\/localdab.org\/wp-content\/uploads\/2025\/12\/DAB-Time-Structure-1024x576.jpg\" alt=\"\" class=\"wp-image-2299\" srcset=\"https:\/\/localdab.org\/wp-content\/uploads\/2025\/12\/DAB-Time-Structure-1024x576.jpg 1024w, https:\/\/localdab.org\/wp-content\/uploads\/2025\/12\/DAB-Time-Structure-300x169.jpg 300w, https:\/\/localdab.org\/wp-content\/uploads\/2025\/12\/DAB-Time-Structure-768x432.jpg 768w, https:\/\/localdab.org\/wp-content\/uploads\/2025\/12\/DAB-Time-Structure.jpg 1280w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><button\n\t\t\tclass=\"lightbox-trigger\"\n\t\t\ttype=\"button\"\n\t\t\taria-haspopup=\"dialog\"\n\t\t\tdata-wp-bind--aria-label=\"state.thisImage.triggerButtonAriaLabel\"\n\t\t\tdata-wp-init=\"callbacks.initTriggerButton\"\n\t\t\tdata-wp-on--click=\"actions.showLightbox\"\n\t\t\tdata-wp-style--right=\"state.thisImage.buttonRight\"\n\t\t\tdata-wp-style--top=\"state.thisImage.buttonTop\"\n\t\t>\n\t\t\t<svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"12\" height=\"12\" fill=\"none\" viewBox=\"0 0 12 12\">\n\t\t\t\t<path fill=\"#fff\" d=\"M2 0a2 2 0 0 0-2 2v2h1.5V2a.5.5 0 0 1 .5-.5h2V0H2Zm2 10.5H2a.5.5 0 0 1-.5-.5V8H0v2a2 2 0 0 0 2 2h2v-1.5ZM8 12v-1.5h2a.5.5 0 0 0 .5-.5V8H12v2a2 2 0 0 1-2 2H8Zm2-12a2 2 0 0 1 2 2v2h-1.5V2a.5.5 0 0 0-.5-.5H8V0h2Z\" \/>\n\t\t\t<\/svg>\n\t\t<\/button><\/figure>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\"><em><a href=\"https:\/\/localdab.org\/index.php\/glossary\/\" data-type=\"page\" data-id=\"15\">Back<\/a><\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>For DAB Mode I, the time structure is derived from the 2048 kHz clock reference, corresponding to a DAB clock period of 1\/2048 kHz = 488.28125 ns.In some DAB literature, this value is also written as 0.48828125 \u00b5s, sometimes with fewer decimal places, but the value above\u2014with eight digits after the decimal point in \u00b5s\u2014is [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"parent":1257,"menu_order":150,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2298","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages\/2298","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/comments?post=2298"}],"version-history":[{"count":3,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages\/2298\/revisions"}],"predecessor-version":[{"id":2304,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages\/2298\/revisions\/2304"}],"up":[{"embeddable":true,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages\/1257"}],"wp:attachment":[{"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/media?parent=2298"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}