{"id":3632,"date":"2021-03-22T16:26:33","date_gmt":"2021-03-22T21:26:33","guid":{"rendered":"https:\/\/www.igp.gob.pe\/observatorios\/radio-observatorio-jicamarca\/?page_id=3632"},"modified":"2021-04-27T16:06:29","modified_gmt":"2021-04-27T21:06:29","slug":"long-pulse-mode","status":"publish","type":"page","link":"https:\/\/www.igp.gob.pe\/observatorios\/radio-observatorio-jicamarca\/?page_id=3632","title":{"rendered":"LONG PULSE MODE"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-page\" data-elementor-id=\"3632\" class=\"elementor elementor-3632\" data-elementor-settings=\"[]\">\n\t\t\t\t\t\t<div class=\"elementor-inner\">\n\t\t\t\t\t\t\t<div class=\"elementor-section-wrap\">\n\t\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-abf5e40 elementor-section-stretched elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"abf5e40\" data-element_type=\"section\" data-settings=\"{&quot;stretch_section&quot;:&quot;section-stretched&quot;}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t\t\t<div class=\"elementor-row\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-6239d2d\" data-id=\"6239d2d\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-column-wrap elementor-element-populated\">\n\t\t\t\t\t\t\t<div class=\"elementor-widget-wrap\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-e9e5664 elementor-widget elementor-widget-text-editor\" data-id=\"e9e5664\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<div class=\"elementor-text-editor elementor-clearfix\"><p>LONG PULSE MODE<\/p><\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-bbf5b1e elementor-section-stretched elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"bbf5b1e\" data-element_type=\"section\" data-settings=\"{&quot;stretch_section&quot;:&quot;section-stretched&quot;}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t\t\t<div class=\"elementor-row\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-2a19685\" data-id=\"2a19685\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-column-wrap elementor-element-populated\">\n\t\t\t\t\t\t\t<div class=\"elementor-widget-wrap\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-0627b52 elementor-widget elementor-widget-text-editor\" data-id=\"0627b52\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<div class=\"elementor-text-editor elementor-clearfix\"><p style=\"text-align: justify;\"><span style=\"font-weight: 400;\">At altitudes for which range resolution is not very important, it is sometimes possible to measure all the lags of the ACF simultaneously using a single long pulse combined with a (mismatched) filter with a short impulse response.\u00a0 In the <\/span><i><span style=\"font-weight: 400;\">F<\/span><\/i><span style=\"font-weight: 400;\"> region of the ionosphere, the scatterers are distributed over a range of more than 1000 km. As a result, the measured spectrum does not represent just a single height, but instead represents a weighted average of spectra from an altitude range equal to the width of the pulse. If the properties of the ionosphere remain constant over such a range, the technique will work well.<\/span><\/p><p style=\"text-align: justify;\"><span style=\"font-weight: 400;\">The frequency resolution obtained using the long pulse technique is inversely proportional to the width of the pulse. Since the incoherent scatter spectrum is relatively smooth, it might be possible to extract useful temperature estimates with a resolution of 500 Hz. The transmitter pulse would then have to be 300 km long. The sample rate must exceed the Nyquist rate in order to avoid aliasing the spectrum.<\/span><\/p><p style=\"text-align: justify;\"><span style=\"font-weight: 400;\">Since the Jicamarca Radio Observatory main antenna cannot be steered more than few degrees from vertical, this long pulse mode can only be used for measurements at high altitudes where the ionospheric parameters are constant over the 300 km extent of the pulse.<\/span><\/p><p style=\"text-align: justify;\"><span style=\"font-weight: 400;\">In the early days, this mode was used to get measurements as high as 10,000 km [e.g., <\/span><a href=\"http:\/\/jro.igp.gob.pe\/publications\/reprints\/1991\/FarleyJATP53(665)91.pdf\"><i><span style=\"font-weight: 400;\">Farley, 1991<\/span><\/i><\/a> <span style=\"font-weight: 400;\">]. Nowadays, this mode is being used in support of most topside and protonospheric measurements including the POLITE campaign. Typical parameters are: IPP=6000 km, PW = 300 km, Receiver bandwidth = 15 km.<\/span><\/p><\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>LONG PULSE MODE At altitudes for which range resolution is not very important, it is sometimes possible to measure all the lags of the ACF simultaneously using a single long pulse combined with a (mismatched) filter with a short impulse response.\u00a0 In the F region of the ionosphere, the scatterers [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":3602,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"page-templates\/template-fullwidth.php","meta":{"footnotes":""},"class_list":["post-3632","page","type-page","status-publish","hentry"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.igp.gob.pe\/observatorios\/radio-observatorio-jicamarca\/index.php?rest_route=\/wp\/v2\/pages\/3632","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.igp.gob.pe\/observatorios\/radio-observatorio-jicamarca\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.igp.gob.pe\/observatorios\/radio-observatorio-jicamarca\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.igp.gob.pe\/observatorios\/radio-observatorio-jicamarca\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.igp.gob.pe\/observatorios\/radio-observatorio-jicamarca\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3632"}],"version-history":[{"count":7,"href":"https:\/\/www.igp.gob.pe\/observatorios\/radio-observatorio-jicamarca\/index.php?rest_route=\/wp\/v2\/pages\/3632\/revisions"}],"predecessor-version":[{"id":5105,"href":"https:\/\/www.igp.gob.pe\/observatorios\/radio-observatorio-jicamarca\/index.php?rest_route=\/wp\/v2\/pages\/3632\/revisions\/5105"}],"up":[{"embeddable":true,"href":"https:\/\/www.igp.gob.pe\/observatorios\/radio-observatorio-jicamarca\/index.php?rest_route=\/wp\/v2\/pages\/3602"}],"wp:attachment":[{"href":"https:\/\/www.igp.gob.pe\/observatorios\/radio-observatorio-jicamarca\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3632"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}