{"id":413,"date":"2015-08-06T14:50:00","date_gmt":"2015-08-06T14:50:00","guid":{"rendered":"http:\/\/machineryequipmentonline.com\/video-equipment\/uncategorized\/tv-cameras-and-analogue-colour-encodingssg-and-timebase-generators-and-camera-power-supplies\/"},"modified":"2015-08-06T14:50:00","modified_gmt":"2015-08-06T14:50:00","slug":"tv-cameras-and-analogue-colour-encodingssg-and-timebase-generators-and-camera-power-supplies","status":"publish","type":"post","link":"http:\/\/machineryequipmentonline.com\/video-equipment\/tv-cameras-and-analogue-colour-encodingssg-and-timebase-generators-and-camera-power-supplies\/","title":{"rendered":"TV CAMERAS AND ANALOGUE COLOUR ENCODING:SSG AND TIMEBASE GENERATORS AND CAMERA POWER SUPPLIES."},"content":{"rendered":"<div class=\"lqzrx6a0dc9156e55b\" ><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.lqzrx6a0dc9156e55b {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.lqzrx6a0dc9156e55b {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.lqzrx6a0dc9156e55b {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.lqzrx6a0dc9156e55b {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.lqzrx6a0dc9156e55b {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<h3 align=\"justify\">SSG AND TIMEBASE GENERATORS<\/h3>\n<p align=\"justify\">The timing waveforms for use throughout the camera are generated in an LSI (Large Scale Integration) IC, with the fundamental clock pulses coming from a very stable quartz crystal reference running at a multiple of <i>f<\/i>sc. Use of a quadruple-frequency clock signal in conjunction with digital counters permits direct derivation of all required phases of subcarrier at 4.43 MHz; no recourse to drift- prone analogue (i.e. LC) phase-shift circuits is required. Further counting of <i>f<\/i>sc (set to exactly 4.433619 MHz by a trimming capacitor at the crystal) renders not only the line and \ufb01eld drive (sync) pulses at 15.625 kHz and 50 kHz respectively, but a half-line pulse at 7.8 kHz (ident) and the required blanking, clamping, gating and burst-\ufb02ag pulses. A complex pulse train is required (Fig. 2.4) during the \ufb01eld sync interval, and a four-\ufb01eld-repeat sequence of burst phase and burst suppression during \ufb01eld blanking (<i>Bru<\/i><i>c<\/i><i>h blanking<\/i>) is necessary to conform fully with the PAL speci\ufb01cation. All these are gener- ated within the SSG chip and distributed as required to all parts of the camera. <\/p>\n<h4 align=\"justify\">Genlock<\/h4>\n<p align=\"justify\">Where the camera is required to operate with others in a \u2018studio\u2019 situation involving vision mixers or faders, the scan generators of all cameras involved must be synchronised so that their line and \ufb01eld scans are time-coincident. To ensure correct colour reproduction their colour subcarriers must also be locked together. Professional camera types have facilities for this, in which the SSG master crystal becomes part of a VXO (Voltage-controlled crystal Oscillator) under the in\ufb02u- ence of a phase-lock-loop (PLL). This can be <i>slaved <\/i>to an incoming CVBS or burst-plus-syncs signal from an external SSG, which may be part of another camera. Variations in the phase response of electrical circuits, and in camera lead lengths usually necessitate a phase control preset at some point \u2013 it is trimmed to match the hue between cameras. <\/p><div class=\"nqvfw6a0dc9156e814\" ><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.nqvfw6a0dc9156e814 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.nqvfw6a0dc9156e814 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.nqvfw6a0dc9156e814 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.nqvfw6a0dc9156e814 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.nqvfw6a0dc9156e814 {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<div class=\"vdgoi6a0dc9156e719\" ><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.vdgoi6a0dc9156e719 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.vdgoi6a0dc9156e719 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.vdgoi6a0dc9156e719 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.vdgoi6a0dc9156e719 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.vdgoi6a0dc9156e719 {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n\n<p align=\"justify\">The advent of \ufb01eld-store memories in consumer equipment has opened the way to a form of genlock which does not depend on the SSGs of the cameras running in synchronism. The video output from one camera is digitised, one \ufb01eld at a time, then written into a large RAM (Random Access Memory). It is read out in accordance with the scan timings of the second camera to achieve the same result as true genlock. This system has the advantage of working with autonomous picture sources like VCRs and TV broadcasts. <\/p>\n<h3 align=\"justify\">CAMERA POWER SUPPLIES<\/h3>\n<p align=\"justify\">A great deal of the design effort for a domestic TV camera is concerned with minimising its power consumption, since it is required to run (in conjunction with its videorecorder section) from a small rechargeable battery. In general the voltage requirement is 4.5 V, 6 V or 7.2 V. Inside the machine, d.c\u2212d.c. converters (see Chapter 11) furnish stabilised supply lines for the various electrical, control, and mechanical sections.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>SSG AND TIMEBASE GENERATORS The timing waveforms for use throughout the camera are generated in an LSI (Large Scale Integration) IC, with the fundamental clock pulses coming from a very stable quartz crystal reference running at a multiple of fsc. Use of a quadruple-frequency clock signal in conjunction with digital counters permits direct derivation of [&hellip;]<br \/><a href=\"http:\/\/machineryequipmentonline.com\/video-equipment\/tv-cameras-and-analogue-colour-encodingssg-and-timebase-generators-and-camera-power-supplies\/\" 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":542,"_links":{"self":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts\/413"}],"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=413"}],"version-history":[{"count":0,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts\/413\/revisions"}],"wp:attachment":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/media?parent=413"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/categories?post=413"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/tags?post=413"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}