{"id":199,"date":"2015-08-31T10:13:00","date_gmt":"2015-08-31T10:13:00","guid":{"rendered":"http:\/\/machineryequipmentonline.com\/video-equipment\/uncategorized\/television-receivers-crt-typerf-oscillator-and-mixer-oscillator\/"},"modified":"2015-08-31T10:13:00","modified_gmt":"2015-08-31T10:13:00","slug":"television-receivers-crt-typerf-oscillator-and-mixer-oscillator","status":"publish","type":"post","link":"http:\/\/machineryequipmentonline.com\/video-equipment\/television-receivers-crt-typerf-oscillator-and-mixer-oscillator\/","title":{"rendered":"Television receivers CRT-type:RF oscillator and Mixer-oscillator."},"content":{"rendered":"<div class=\"trlfz6a0dbe3bc5208\" ><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.trlfz6a0dbe3bc5208 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.trlfz6a0dbe3bc5208 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.trlfz6a0dbe3bc5208 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.trlfz6a0dbe3bc5208 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.trlfz6a0dbe3bc5208 {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<h3 align=\"justify\">RF oscillator<\/h3>\n<p align=\"justify\">At the UHF range of frequencies, feedback in the oscillator is obtained by mutual inductance, employing lecher lines to form a Hartley or a Colpitts oscillator. Use may also be made of the inter-electrode capacitors of the transistor. The circuit in Figure 13.5 shows a common-base Colpitts oscil- lator in which inter-electrode capacitors <i>C<\/i>ce (between collector and emit- ter) and <i>C<\/i>be (between emitter and base) provide the necessary feedback for sustained oscillation. <i>C<\/i>ce in series with <i>C<\/i>be effectively fall across the output developed between the collector and base. Part of this output, that part across <i>C<\/i>be, is fed back into the input between the emitter and base. R1 is the emitter resistor, R2\/R3 is the base bias chain with C2 as the base or bias decoupling capacitor and TL1 is the output lecher line resonating with <i>varicap diode <\/i>C3. A varicap diode is a reversed-biased diode which looks like a capacitance as far as the circuit is concerned. The value of the capacitance it represents is determined by the reverse-bias voltage.  <\/p><div class=\"ujzfq6a0dbe3bc5397\" ><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.ujzfq6a0dbe3bc5397 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.ujzfq6a0dbe3bc5397 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.ujzfq6a0dbe3bc5397 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.ujzfq6a0dbe3bc5397 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.ujzfq6a0dbe3bc5397 {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<div class=\"lizxb6a0dbe3bc52df\" ><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.lizxb6a0dbe3bc52df {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.lizxb6a0dbe3bc52df {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.lizxb6a0dbe3bc52df {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.lizxb6a0dbe3bc52df {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.lizxb6a0dbe3bc52df {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n\n<h3 align=\"justify\">Mixer-oscillator<\/h3>\n<p align=\"justify\">The purpose of the mixer-oscillator stage is to change the incoming UHF carrier frequency to a common IF, a technique known as <i>super-hete<\/i><i>r<\/i><i>odyne<\/i><i> <\/i>(<i>supe<\/i><i>r<\/i><i>he<\/i><i>t <\/i>for short). Frequency changing may be achieved either through multiplication or addition. Addition is the preferred method for TV tuners. A single transistor is made to oscillate at frequency <i>f<\/i>o, which is 39.5 MHz above the selected channel frequency <i>f<\/i>c. The non-linear part of the transis- tor characteristic is then used to produce the sum ( <i>f<\/i>o + <i>f<\/i>c) and the difference ( <i>f<\/i>o &#8211; <i>f<\/i>c) of the two frequencies together with the two original frequencies, <i>f<\/i>o and <i>f<\/i>c. A tuned circuit at the output is then made to select the frequency dif- ference, <i>f<\/i>o &#8211; <i>f<\/i>c = 39.5 MHz.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>RF oscillator At the UHF range of frequencies, feedback in the oscillator is obtained by mutual inductance, employing lecher lines to form a Hartley or a Colpitts oscillator. Use may also be made of the inter-electrode capacitors of the transistor. The circuit in Figure 13.5 shows a common-base Colpitts oscil- lator in which inter-electrode capacitors [&hellip;]<br \/><a href=\"http:\/\/machineryequipmentonline.com\/video-equipment\/television-receivers-crt-typerf-oscillator-and-mixer-oscillator\/\" 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":822,"_links":{"self":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts\/199"}],"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=199"}],"version-history":[{"count":0,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts\/199\/revisions"}],"wp:attachment":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/media?parent=199"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/categories?post=199"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/tags?post=199"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}