{"id":17,"date":"2015-09-19T20:41:22","date_gmt":"2015-09-19T20:41:22","guid":{"rendered":"https:\/\/geekblog.febo.com\/wp\/?p=17"},"modified":"2019-03-14T22:44:43","modified_gmt":"2019-03-14T22:44:43","slug":"testing-a-60s-vintage-sulzer-ocxo-with-a-twist","status":"publish","type":"post","link":"https:\/\/blog.febo.com\/?p=17","title":{"rendered":"Testing a &#8217;60s vintage Sulzer OCXO &#8212; with a twist"},"content":{"rendered":"<p>Over the years I&#8217;ve acquired a whole bunch of Sulzer OCXOs.\u00a0 One is dead, several have oven temperature control problems, but I have three powered up in the rack that still work amazingly well.<\/p>\n<p>This one, Sulzer #3, is particularly interesting.\u00a0 It&#8217;s not on the standard 2.5 or 5 MHz frequency.\u00a0 Instead it runs at 5.006 880 MHz.\u00a0 That happens to be a submultiple of the Cesium transition frequency.\u00a0 And I&#8217;ve been told, but unfortunately can&#8217;t prove, that this unit came out of NBS in Boulder.\u00a0 Hmmm&#8230;<\/p>\n<p>I measured it for 2 hours against an OSA 8607-008 BVA, and for 10 days against an HP5065A to get an idea of aging.\u00a0 Sulzer #3 has been running uninterruptedly for just about 4 years at this point.<\/p>\n<p><a href=\"http:\/\/blog.febo.com\/wp-content\/uploads\/2015\/09\/sulzer_3_vs_bva_and_hp5065a_17Sep15.png\" data-rel=\"penci-gallery-image-content\" ><img decoding=\"async\" class=\"alignnone size-medium wp-image-18\" src=\"http:\/\/blog.febo.com\/wp-content\/uploads\/2015\/09\/sulzer_3_vs_bva_and_hp5065a_17Sep15-300x151.png\" alt=\"sulzer_3_vs_bva_and_hp5065a_17Sep15\" width=\"300\" height=\"151\" srcset=\"https:\/\/blog.febo.com\/wp-content\/uploads\/2015\/09\/sulzer_3_vs_bva_and_hp5065a_17Sep15-300x151.png 300w, https:\/\/blog.febo.com\/wp-content\/uploads\/2015\/09\/sulzer_3_vs_bva_and_hp5065a_17Sep15-1024x514.png 1024w, https:\/\/blog.febo.com\/wp-content\/uploads\/2015\/09\/sulzer_3_vs_bva_and_hp5065a_17Sep15.png 1366w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p>That&#8217;s not too shabby.<\/p>\n<p>I also did a phase noise measurement against both a Wenzel ULN and the BVA.<\/p>\n<p><a href=\"http:\/\/blog.febo.com\/wp-content\/uploads\/2015\/09\/sulzer_3_pn_vs_uln_and_bva_10m_6Sep15.png\" data-rel=\"penci-gallery-image-content\" ><img decoding=\"async\" class=\"alignnone size-medium wp-image-19\" src=\"http:\/\/blog.febo.com\/wp-content\/uploads\/2015\/09\/sulzer_3_pn_vs_uln_and_bva_10m_6Sep15-300x151.png\" alt=\"sulzer_3_pn_vs_uln_and_bva_10m_6Sep15\" width=\"300\" height=\"151\" srcset=\"https:\/\/blog.febo.com\/wp-content\/uploads\/2015\/09\/sulzer_3_pn_vs_uln_and_bva_10m_6Sep15-300x151.png 300w, https:\/\/blog.febo.com\/wp-content\/uploads\/2015\/09\/sulzer_3_pn_vs_uln_and_bva_10m_6Sep15-1024x514.png 1024w, https:\/\/blog.febo.com\/wp-content\/uploads\/2015\/09\/sulzer_3_pn_vs_uln_and_bva_10m_6Sep15.png 1366w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p>Note the steep drop at about 500 Hz.\u00a0 I am guessing there is a crystal filter in the unit to drop spurs.\u00a0 -115 dBc\/Hz at a 1 Hertz offset isn&#8217;t too shabby; in fact, that&#8217;s about what both the ULN and BVA are rated for, so the chances are the actual value is a bit better.\u00a0 The noise floor isn&#8217;t all that hot, but let&#8217;s give 1960-era designers a break!<\/p>\n<p>I&#8217;d really love to know if this oscillator was involved with NBS-2 or NBS-3.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Over the years I&#8217;ve acquired a whole bunch of Sulzer OCXOs.\u00a0 One is dead, several have oven temperature control problems, but I have three powered up in the rack that&hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_lmt_disableupdate":"","_lmt_disable":"","ngg_post_thumbnail":0,"footnotes":""},"categories":[2],"tags":[],"class_list":["post-17","post","type-post","status-publish","format-standard","hentry","category-time-and-frequency"],"_links":{"self":[{"href":"https:\/\/blog.febo.com\/index.php?rest_route=\/wp\/v2\/posts\/17","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.febo.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.febo.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.febo.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.febo.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=17"}],"version-history":[{"count":4,"href":"https:\/\/blog.febo.com\/index.php?rest_route=\/wp\/v2\/posts\/17\/revisions"}],"predecessor-version":[{"id":420,"href":"https:\/\/blog.febo.com\/index.php?rest_route=\/wp\/v2\/posts\/17\/revisions\/420"}],"wp:attachment":[{"href":"https:\/\/blog.febo.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=17"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.febo.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=17"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.febo.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=17"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}