{"id":235,"date":"2015-08-29T15:49:00","date_gmt":"2015-08-29T15:49:00","guid":{"rendered":"http:\/\/machineryequipmentonline.com\/video-equipment\/uncategorized\/channel-encodingphase-shift-keying\/"},"modified":"2015-08-29T15:49:00","modified_gmt":"2015-08-29T15:49:00","slug":"channel-encodingphase-shift-keying","status":"publish","type":"post","link":"http:\/\/machineryequipmentonline.com\/video-equipment\/channel-encodingphase-shift-keying\/","title":{"rendered":"Channel encoding:Phase shift keying"},"content":{"rendered":"<div class=\"telno6a0dc91a76c9d\" ><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.telno6a0dc91a76c9d {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.telno6a0dc91a76c9d {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.telno6a0dc91a76c9d {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.telno6a0dc91a76c9d {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.telno6a0dc91a76c9d {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<h3 align=\"justify\">Phase shift keying<\/h3>\n<p align=\"justify\">A digital signal has only two states, 1 and 0, and when it is used to mod- ulate a carrier, only two states of the carrier amplitude, frequency or phase are necessary to convey the digital information. In terms of bandwidth, the most economical form of modulation is phase modulation, known as phase shift keying (PSK). Here, the carrier frequency remains constant while its phase changes in discrete quantities in accordance with the logic state of the data bit. Binary PSK (BPSK) is a two-phase modulation tech- nique in which the carrier is transmitted with a reference phase to indicate logic 1 and a phase change of 180\u00ba to indicate logic 0.  <\/p>\n<p align=\"justify\">In quadrature phase shift keying (QPSK), also known as 4-phase PSK, the serial bitstream is first converted into a 2-bit parallel format using a  <\/p>\n<p align=\"justify\"><a href=\"http:\/\/lh3.googleusercontent.com\/-20Cvy5JJ9Xc\/VeHUO2w8RlI\/AAAAAAAB3-A\/zaAjjANIGtc\/s1600-h\/Channel-encoding-05682.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=\"Channel encoding-0568\" border=\"0\" alt=\"Channel encoding-0568\" src=\"http:\/\/lh3.googleusercontent.com\/-Jb_xl7uhta8\/VeHUX_Zr_nI\/AAAAAAAB3_M\/G5c20Tl-9dY\/Channel-encoding-0568_thumb.jpg?imgmax=800\" width=\"353\" height=\"286\" \/><\/a>  <\/p>\n<p align=\"justify\">serial-to-parallel converter. The instantaneous states of each pair of bits, known as dibits, can take one of four combinations, namely 00, 01, 10 and  <\/p>\n<p align=\"justify\">11. For each of these combinations, the carrier is set to a particular phase angle (Table 8.1). The carrier has four phases: 45\u00ba, 135\u00ba, 225\u00ba and 315\u00ba. For example, data 00 and 10 are represented by 45\u00ba and 225\u00ba, respectively. The four phases are obtained from two quadrature (at right angles) carriers having the same frequency (Figure 8.4) I (in-phase) and Q (quadrature). Each phase is used to represent a 2-bit combination known as a <i>symbol <\/i>(Table 8.1). As can be seen, the bit rate is twice the symbol rate (also known as the <i>baud rate<\/i>). It is the symbol rate, i.e. the rate of phase change that determines the bandwidth. For the same bandwidth, twice as much infor- mation can thus be sent using QPSK compared with BPSK.  <\/p><div class=\"bnwkj6a0dc91a76e6b\" ><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.bnwkj6a0dc91a76e6b {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.bnwkj6a0dc91a76e6b {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.bnwkj6a0dc91a76e6b {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.bnwkj6a0dc91a76e6b {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.bnwkj6a0dc91a76e6b {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<div class=\"rivvo6a0dc91a76d8f\" ><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.rivvo6a0dc91a76d8f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.rivvo6a0dc91a76d8f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.rivvo6a0dc91a76d8f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.rivvo6a0dc91a76d8f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.rivvo6a0dc91a76d8f {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n\n<p align=\"justify\">Differential phase shift keying (DPSK) has no specific reference phase. A phase shift occurs only if the current bit is different from the previous bit. The phase reference is therefore the previously transmitted signal phase. The advantage of this technique is that the receiver and the trans- mitter do not have to maintain an absolute phase reference with which the phase of the received signal is compared. DQPSK combines the advan- tages of QPSK and DPSK.  <\/p>\n<p align=\"justify\">Phase shift keying may be improved by increasing the number of carrier phase angles from 4 in the case of QPSK to 8 or 16 in the case of 8-PSK and 16-PSK, respectively. In 8-PSK, the carrier may have one of eight different phase angles (Figure 8.5) with each phasor representing one of eight 3-bit combinations.  <\/p>\n<p align=\"justify\"><a href=\"http:\/\/lh3.googleusercontent.com\/-Fw6z5L7opcQ\/VeHUbEgFh0I\/AAAAAAAB3_g\/W7rosj0YvM4\/s1600-h\/Channel-encoding-05692.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=\"Channel encoding-0569\" border=\"0\" alt=\"Channel encoding-0569\" src=\"http:\/\/lh3.googleusercontent.com\/-Ic5k36S81_w\/VeHUeeApmlI\/AAAAAAAB3_w\/PlkHNyrw71I\/Channel-encoding-0569_thumb.jpg?imgmax=800\" width=\"385\" height=\"456\" \/><\/a>  <\/p>\n<p align=\"justify\">\n<p align=\"justify\">\n<p align=\"justify\">\n","protected":false},"excerpt":{"rendered":"<p>Phase shift keying A digital signal has only two states, 1 and 0, and when it is used to mod- ulate a carrier, only two states of the carrier amplitude, frequency or phase are necessary to convey the digital information. In terms of bandwidth, the most economical form of modulation is phase modulation, known as [&hellip;]<br \/><a href=\"http:\/\/machineryequipmentonline.com\/video-equipment\/channel-encodingphase-shift-keying\/\" 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":657,"_links":{"self":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts\/235"}],"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=235"}],"version-history":[{"count":0,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts\/235\/revisions"}],"wp:attachment":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/media?parent=235"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/categories?post=235"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/tags?post=235"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}