{"id":143,"date":"2015-09-01T15:36:00","date_gmt":"2015-09-01T15:36:00","guid":{"rendered":"http:\/\/machineryequipmentonline.com\/video-equipment\/uncategorized\/tv-sound-mono-and-nicamdqpsk-decoder\/"},"modified":"2015-09-01T15:36:00","modified_gmt":"2015-09-01T15:36:00","slug":"tv-sound-mono-and-nicamdqpsk-decoder","status":"publish","type":"post","link":"http:\/\/machineryequipmentonline.com\/video-equipment\/tv-sound-mono-and-nicamdqpsk-decoder\/","title":{"rendered":"TV sound, mono and NICAM:DQPSK decoder"},"content":{"rendered":"<div class=\"ncktz6a0dc85197a06\" ><script type=\"text\/javascript\">\n\tatOptions = {\n\t\t'key' : '61e5902552e2353963d8d2f1bd1f4a8f',\n\t\t'format' : 'iframe',\n\t\t'height' : 250,\n\t\t'width' : 300,\n\t\t'params' : {}\n\t};\n<\/script>\n<script type=\"text\/javascript\" src=\"\/\/www.highperformanceformat.com\/61e5902552e2353963d8d2f1bd1f4a8f\/invoke.js\"><\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.ncktz6a0dc85197a06 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.ncktz6a0dc85197a06 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.ncktz6a0dc85197a06 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.ncktz6a0dc85197a06 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.ncktz6a0dc85197a06 {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<h3 align=\"justify\">DQPSK decoder<\/h3>\n<p align=\"justify\">The phase demodulator or detector works on the same principles as an FM detector in which a variation in phase (or frequency) produces a variation in the d.c. output. In the case of two-phase modulation, the d.c. out- put of the detector has two distinct values, representing logic 1 and logic  <\/p>\n<p align=\"justify\">0. However, in the case of quadrature, i.e. four-phase modulation, the out- put of the detector is ambiguous. The same output is obtained for a 90\u00b0 and 270\u00b0 phase shifts. Similarly for phase shifts of 0\u00b0 and 180\u00b0. In order to resolve the ambiguities, a second phase detector operating in quadrature (90\u00b0) is used. Figure 17.10 shows the main elements of a DQPSK demodulator using an in-phase phase detector (PDI) and a quadrature phase  <\/p>\n<p align=\"justify\"><a href=\"http:\/\/lh3.googleusercontent.com\/-aR6xceMHPP4\/VeXF3shCi-I\/AAAAAAAB6JI\/plxcS1Cc8Dg\/s1600-h\/Television-and-Video-Technology-0068%25255B1%25255D.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-right-width: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top-width: 0px; border-bottom-width: 0px; border-left-width: 0px; padding-top: 0px\" title=\"Television and Video Technology-0068\" border=\"0\" alt=\"Television and Video Technology-0068\" src=\"http:\/\/lh3.googleusercontent.com\/-q9QZoHjpsnw\/VeXF54zA7fI\/AAAAAAAB6JU\/09ROQmvmz-s\/Television-and-Video-Technology-0068%25255B2%25255D.jpg?imgmax=800\" width=\"407\" height=\"276\" \/><\/a>  <\/p><div class=\"rmapk6a0dc85197b19\" ><script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-0778475562755157\"\n     crossorigin=\"anonymous\"><\/script>\n<!-- 300x600 television-and-video -->\n<ins class=\"adsbygoogle\"\n     style=\"display:inline-block;width:300px;height:600px\"\n     data-ad-client=\"ca-pub-0778475562755157\"\n     data-ad-slot=\"6549443290\"><\/ins>\n<script>\n     (adsbygoogle = window.adsbygoogle || []).push({});\n<\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.rmapk6a0dc85197b19 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.rmapk6a0dc85197b19 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.rmapk6a0dc85197b19 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.rmapk6a0dc85197b19 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.rmapk6a0dc85197b19 {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<div class=\"hlofz6a0dc85197a9a\" ><script type=\"text\/javascript\">\n\tatOptions = {\n\t\t'key' : '0c1eb4c533eaedb7b996f49a5a4983a9',\n\t\t'format' : 'iframe',\n\t\t'height' : 300,\n\t\t'width' : 160,\n\t\t'params' : {}\n\t};\n<\/script>\n<script type=\"text\/javascript\" src=\"\/\/www.highperformanceformat.com\/0c1eb4c533eaedb7b996f49a5a4983a9\/invoke.js\"><\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.hlofz6a0dc85197a9a {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.hlofz6a0dc85197a9a {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.hlofz6a0dc85197a9a {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.hlofz6a0dc85197a9a {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.hlofz6a0dc85197a9a {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n\n<p align=\"justify\">detector (PDQ). The outputs from the two-phase detectors, data I and Q, are fed into a data recovery circuit which reproduces the original 728-bit serial data stream. The 6.552 MHz reference carrier frequency is generated by a carrier recovery circuit which includes a crystal-tuned voltage- controlled oscillator (VCO) and a phase-locked loop (PLL).  <\/p>\n<p align=\"justify\">The data recovery circuit includes a second PLL locked to the bit rate of 728 kHz. In order to ensure a \u2018clean\u2019 bit rate clock, a master system clock which is a multiple of the bit rate is used. In this case, a clock frequency of 728 X 8 = 5824 kHz = 5.824 MHz is used. The bit rate is then retrieved by dividing the master system clock by eight. The I and Q data streams from the DQPSK detector are fed into a differential logic decoder, which pro- duces the corresponding 2-bit parallel data. The pairs of parallel data are then fed into a parallel-to-serial converter, which reconstructs the original 728-bit serial stream before going to the NICAM decoder.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>DQPSK decoder The phase demodulator or detector works on the same principles as an FM detector in which a variation in phase (or frequency) produces a variation in the d.c. output. In the case of two-phase modulation, the d.c. out- put of the detector has two distinct values, representing logic 1 and logic 0. However, [&hellip;]<br \/><a href=\"http:\/\/machineryequipmentonline.com\/video-equipment\/tv-sound-mono-and-nicamdqpsk-decoder\/\" class=\"more-link\" >Continue reading&#8230;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"aioseo_notices":[],"views":614,"_links":{"self":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts\/143"}],"collection":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/comments?post=143"}],"version-history":[{"count":0,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts\/143\/revisions"}],"wp:attachment":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/media?parent=143"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/categories?post=143"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/tags?post=143"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}