{"id":4344,"date":"2019-06-14T01:52:22","date_gmt":"2019-06-13T23:52:22","guid":{"rendered":"https:\/\/demdlx704as001.ad.harman.com\/?p=4344"},"modified":"2023-11-24T08:55:39","modified_gmt":"2023-11-24T07:55:39","slug":"noiseest","status":"publish","type":"post","link":"https:\/\/audioworx.transfunnel.co\/old\/?p=4344","title":{"rendered":"NoiseEst"},"content":{"rendered":"<p><span style=\"font-family: 'times new roman', times, serif;\">The purpose of the noise estimation module is to estimate the level of noise in the vehicle coming from the engine, the road, and other error sources while music is playing. Inputs given to the module are the digital output sound data in its final stage before it is sent to the DACs, and the feedback coming from a microphone mounted somewhere in the vehicle cabin. When users know what is sent to each loudspeaker, they can correlate that information with the microphone input to get a channel estimate.<\/span><\/p>\n<p><span style=\"font-family: 'times new roman', times, serif;\">This is only a component of the complete VNC implementation.<\/span><\/p>\n<p><span style=\"font-family: 'times new roman', times, serif;\">The coefficients get dynamically calculated and updated. This approach has the benefit of being able to adapt to changing circumstances. For example, if a window is opened while driving, the noise increases. In addition to increased noise, the optimal channel estimate changes as well.<\/span><\/p>\n<p class=\"heading\"><strong>Control Parameters<\/strong><\/p>\n<ul>\n<li><span style=\"font-family: 'times new roman', times, serif;\">Door slam count: Number of frames exceeding the threshold. (This count is to be used to detect door slams.)<\/span><\/li>\n<li><span style=\"font-family: 'times new roman', times, serif;\">Err smallest RMS: Small error threshold.<\/span><\/li>\n<li><span style=\"font-family: 'times new roman', times, serif;\">Err median RMS: Error estimation after median filtering.<\/span><\/li>\n<li><span style=\"font-family: 'times new roman', times, serif;\">Audio channels: Audio channel range varies from 2 to 7.<\/span><\/li>\n<\/ul>\n<p class=\"heading\"><strong>Tuning Parameters<\/strong><\/p>\n<table style=\"border-collapse: collapse; width: 100%; height: 423px;\" border=\"1\">\n<tbody>\n<tr style=\"height: 28px;\">\n<td class=\"table-head\" style=\"width: 21.6023%; height: 28px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Parameter<\/span><\/strong><\/td>\n<td class=\"table-head\" style=\"width: 13.445%; height: 28px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Min<\/span><\/strong><\/td>\n<td class=\"table-head\" style=\"width: 13.4451%; height: 28px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Max<\/span><\/strong><\/td>\n<td class=\"table-head\" style=\"width: 13.0808%; height: 28px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Default<\/span><\/strong><\/td>\n<td class=\"table-head\" style=\"width: 38.4268%; height: 28px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Description<\/span><\/strong><\/td>\n<\/tr>\n<tr style=\"height: 26px;\">\n<td style=\"width: 21.6023%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Error Decay Time<\/span><\/strong><\/td>\n<td style=\"width: 13.445%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<td style=\"width: 13.4451%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">10.0<\/span><\/td>\n<td style=\"width: 13.0808%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.05<\/span><\/td>\n<td style=\"width: 38.4268%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">Error decay time is measured in milliseconds.<\/span><\/td>\n<\/tr>\n<tr style=\"height: 26px;\">\n<td style=\"width: 21.6023%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Mic Gain<\/span><\/strong><\/td>\n<td style=\"width: 13.445%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">-20.0<\/span><\/td>\n<td style=\"width: 13.4451%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">20.0<\/span><\/td>\n<td style=\"width: 13.0808%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<td style=\"width: 38.4268%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">Microphone gain measured in dB.<\/span><\/td>\n<\/tr>\n<tr style=\"height: 26px;\">\n<td style=\"width: 21.6023%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Stepsize<\/span><\/strong><\/td>\n<td style=\"width: 13.445%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<td style=\"width: 13.4451%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">5.0<\/span><\/td>\n<td style=\"width: 13.0808%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.03<\/span><\/td>\n<td style=\"width: 38.4268%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">NLMS step size.<\/span><\/td>\n<\/tr>\n<tr style=\"height: 53px;\">\n<td style=\"width: 21.6023%; height: 53px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Powersum Min<\/span><\/strong><\/td>\n<td style=\"width: 13.445%; height: 53px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<td style=\"width: 13.4451%; height: 53px;\"><span style=\"font-family: 'times new roman', times, serif;\">1000.0<\/span><\/td>\n<td style=\"width: 13.0808%; height: 53px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.003<\/span><\/td>\n<td style=\"width: 38.4268%; height: 53px;\"><span style=\"font-family: 'times new roman', times, serif;\">Minimum power value, NLMS parameter. Lower bound for input signal when calculating NLMS step size.<\/span><\/td>\n<\/tr>\n<tr style=\"height: 26px;\">\n<td style=\"width: 21.6023%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Doorslam Threshold<\/span><\/strong><\/td>\n<td style=\"width: 13.445%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<td style=\"width: 13.4451%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">1000.0<\/span><\/td>\n<td style=\"width: 13.0808%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">1.2<\/span><\/td>\n<td style=\"width: 38.4268%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">Upper bound for door slam detection<\/span><\/td>\n<\/tr>\n<tr style=\"height: 26px;\">\n<td style=\"width: 21.6023%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Power Threshold<\/span><\/strong><\/td>\n<td style=\"width: 13.445%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<td style=\"width: 13.4451%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">1000.0<\/span><\/td>\n<td style=\"width: 13.0808%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.003<\/span><\/td>\n<td style=\"width: 38.4268%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">Threshold for which input power leads to coefficients update<\/span><\/td>\n<\/tr>\n<tr style=\"height: 26px;\">\n<td style=\"width: 21.6023%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Doorslam Timeout<\/span><\/strong><\/td>\n<td style=\"width: 13.445%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<td style=\"width: 13.4451%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">10.0<\/span><\/td>\n<td style=\"width: 13.0808%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<td style=\"width: 38.4268%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">Door slam detection timeout<\/span><\/td>\n<\/tr>\n<tr style=\"height: 26px;\">\n<td style=\"width: 21.6023%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Readapt Timeout<\/span><\/strong><\/td>\n<td style=\"width: 13.445%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<td style=\"width: 13.4451%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">10.0<\/span><\/td>\n<td style=\"width: 13.0808%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<td style=\"width: 38.4268%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">Open window enforce re-adaptation timeout<\/span><\/td>\n<\/tr>\n<tr style=\"height: 80px;\">\n<td style=\"width: 21.6023%; height: 80px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Tuning channel<\/span><\/strong><\/td>\n<td style=\"width: 13.445%; height: 80px;\"><span style=\"font-family: 'times new roman', times, serif;\">1<\/span><\/td>\n<td style=\"width: 13.4451%; height: 80px;\"><span style=\"font-family: 'times new roman', times, serif;\">(Num of channels -1)<\/span><\/td>\n<td style=\"width: 13.0808%; height: 80px;\"><span style=\"font-family: 'times new roman', times, serif;\">1<\/span><\/td>\n<td style=\"width: 38.4268%; height: 80px;\"><span style=\"font-family: 'times new roman', times, serif;\">Selection of channel for which the adaptive coefficients get copied over to the static coefficients on enabling tuning (see \u201cTuning enabled\u201d)<\/span><\/td>\n<\/tr>\n<tr style=\"height: 80px;\">\n<td style=\"width: 21.6023%; height: 80px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Tuning enabled<\/span><\/strong><\/td>\n<td style=\"width: 13.445%; height: 80px;\"><span style=\"font-family: 'times new roman', times, serif;\">0<\/span><\/td>\n<td style=\"width: 13.4451%; height: 80px;\"><span style=\"font-family: 'times new roman', times, serif;\">1<\/span><\/td>\n<td style=\"width: 13.0808%; height: 80px;\"><span style=\"font-family: 'times new roman', times, serif;\">0<\/span><\/td>\n<td style=\"width: 38.4268%; height: 80px;\"><span style=\"font-family: 'times new roman', times, serif;\">Enable copying the adaptive filter coefficients of the selected channel (see \u201cTuning channel\u201d) to the corresponding static filter coefficients<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"heading\"><strong><span style=\"font-family: 'times new roman', times, serif;\">FIR coefficients<\/span><\/strong><\/p>\n<p><span style=\"font-family: 'times new roman', times, serif;\">The FIR coefficients for the static and adaptive filters are arranged as follows.<\/span><\/p>\n<p><span style=\"font-family: 'times new roman', times, serif;\">The number of static and adaptive filter coefficient arrays depends on the number of entertainment channels (number of audio input channels \u2013 1). For each entertainment channel there is a static and an adaptive filter coefficient set.<\/span><\/p>\n<p><span style=\"font-family: 'times new roman', times, serif;\">Table\u00a0 shows the case of one entertainment channel, which means there is one FIR static coefficients array and one FIR adaptive coefficients array. If the number of entertainment channels is higher, then first the arrays of FIR static coefficients are allocated then the arrays of FIR adaptive coefficients.<\/span><\/p>\n<table style=\"border-collapse: collapse; width: 100%; height: 130px;\" border=\"1\">\n<tbody>\n<tr style=\"height: 26px;\">\n<td class=\"table-head\" style=\"width: 25%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Parameter<\/span><\/strong><\/td>\n<td class=\"table-head\" style=\"width: 25%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Offset<\/span><\/strong><\/td>\n<td class=\"table-head\" style=\"width: 25%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Range<\/span><\/strong><\/td>\n<td class=\"table-head\" style=\"width: 25%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">Default value<\/span><\/strong><\/td>\n<\/tr>\n<tr style=\"height: 26px;\">\n<td style=\"width: 25%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">FIR static 1 coefficients<\/span><\/strong><\/td>\n<td style=\"width: 25%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">40<\/span><\/td>\n<td style=\"width: 25%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">-9999.0 \u2013 9999.0<\/span><\/td>\n<td style=\"width: 25%; height: 26px;\" width=\"123\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<\/tr>\n<tr style=\"height: 26px;\">\n<td style=\"width: 25%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">FIR static 2 coefficients<\/span><\/strong><\/td>\n<td style=\"width: 25%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">1064<\/span><\/td>\n<td style=\"width: 25%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">-9999.0 \u2013 9999.0<\/span><\/td>\n<td style=\"width: 25%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<\/tr>\n<tr style=\"height: 26px;\">\n<td style=\"width: 25%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">FIR adaptive 1 coefficients<\/span><\/strong><\/td>\n<td style=\"width: 25%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">2088<\/span><\/td>\n<td style=\"width: 25%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">-9999.0 \u2013 9999.0<\/span><\/td>\n<td style=\"width: 25%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<\/tr>\n<tr style=\"height: 26px;\">\n<td style=\"width: 25%; height: 26px;\"><strong><span style=\"font-family: 'times new roman', times, serif;\">FIR adaptive 2 coefficients<\/span><\/strong><\/td>\n<td style=\"width: 25%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">3112<\/span><\/td>\n<td style=\"width: 25%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">-9999.0 \u2013 9999.0<\/span><\/td>\n<td style=\"width: 25%; height: 26px;\"><span style=\"font-family: 'times new roman', times, serif;\">0.0<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><span style=\"font-family: 'times new roman', times, serif;\">Each FIR coefficient array stores the filter coefficients in reverse order compared to the common understanding of FIR coefficients, meaning the last value in the array of one filter set is the first coefficient of the FIR filter.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The purpose of the noise estimation module is to estimate the level of noise in the vehicle coming from the engine, the road, and other error sources while music is playing. Inputs given to the module are the digital output sound data in its final stage before it is sent to the DACs, and the [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ocean_post_layout":"","ocean_both_sidebars_style":"","ocean_both_sidebars_content_width":0,"ocean_both_sidebars_sidebars_width":0,"ocean_sidebar":"0","ocean_second_sidebar":"0","ocean_disable_margins":"enable","ocean_add_body_class":"","ocean_shortcode_before_top_bar":"","ocean_shortcode_after_top_bar":"","ocean_shortcode_before_header":"","ocean_shortcode_after_header":"","ocean_has_shortcode":"","ocean_shortcode_after_title":"","ocean_shortcode_before_footer_widgets":"","ocean_shortcode_after_footer_widgets":"","ocean_shortcode_before_footer_bottom":"","ocean_shortcode_after_footer_bottom":"","ocean_display_top_bar":"default","ocean_display_header":"default","ocean_header_style":"","ocean_center_header_left_menu":"0","ocean_custom_header_template":"0","ocean_custom_logo":0,"ocean_custom_retina_logo":0,"ocean_custom_logo_max_width":0,"ocean_custom_logo_tablet_max_width":0,"ocean_custom_logo_mobile_max_width":0,"ocean_custom_logo_max_height":0,"ocean_custom_logo_tablet_max_height":0,"ocean_custom_logo_mobile_max_height":0,"ocean_header_custom_menu":"0","ocean_menu_typo_font_family":"0","ocean_menu_typo_font_subset":"","ocean_menu_typo_font_size":0,"ocean_menu_typo_font_size_tablet":0,"ocean_menu_typo_font_size_mobile":0,"ocean_menu_typo_font_size_unit":"px","ocean_menu_typo_font_weight":"","ocean_menu_typo_font_weight_tablet":"","ocean_menu_typo_font_weight_mobile":"","ocean_menu_typo_transform":"","ocean_menu_typo_transform_tablet":"","ocean_menu_typo_transform_mobile":"","ocean_menu_typo_line_height":0,"ocean_menu_typo_line_height_tablet":0,"ocean_menu_typo_line_height_mobile":0,"ocean_menu_typo_line_height_unit":"","ocean_menu_typo_spacing":0,"ocean_menu_typo_spacing_tablet":0,"ocean_menu_typo_spacing_mobile":0,"ocean_menu_typo_spacing_unit":"","ocean_menu_link_color":"","ocean_menu_link_color_hover":"","ocean_menu_link_color_active":"","ocean_menu_link_background":"","ocean_menu_link_hover_background":"","ocean_menu_link_active_background":"","ocean_menu_social_links_bg":"","ocean_menu_social_hover_links_bg":"","ocean_menu_social_links_color":"","ocean_menu_social_hover_links_color":"","ocean_disable_title":"default","ocean_disable_heading":"default","ocean_post_title":"","ocean_post_subheading":"","ocean_post_title_style":"","ocean_post_title_background_color":"","ocean_post_title_background":0,"ocean_post_title_bg_image_position":"","ocean_post_title_bg_image_attachment":"","ocean_post_title_bg_image_repeat":"","ocean_post_title_bg_image_size":"","ocean_post_title_height":0,"ocean_post_title_bg_overlay":0.5,"ocean_post_title_bg_overlay_color":"","ocean_disable_breadcrumbs":"default","ocean_breadcrumbs_color":"","ocean_breadcrumbs_separator_color":"","ocean_breadcrumbs_links_color":"","ocean_breadcrumbs_links_hover_color":"","ocean_display_footer_widgets":"default","ocean_display_footer_bottom":"default","ocean_custom_footer_template":"0","footnotes":"","ocean_post_oembed":"","ocean_post_self_hosted_media":"","ocean_post_video_embed":"","ocean_link_format":"","ocean_link_format_target":"self","ocean_quote_format":"","ocean_quote_format_link":"post","ocean_gallery_link_images":"off","ocean_gallery_id":[]},"categories":[164,315],"tags":[],"coauthors":[165],"_links":{"self":[{"href":"https:\/\/audioworx.transfunnel.co\/old\/index.php?rest_route=\/wp\/v2\/posts\/4344"}],"collection":[{"href":"https:\/\/audioworx.transfunnel.co\/old\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/audioworx.transfunnel.co\/old\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/audioworx.transfunnel.co\/old\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/audioworx.transfunnel.co\/old\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4344"}],"version-history":[{"count":20,"href":"https:\/\/audioworx.transfunnel.co\/old\/index.php?rest_route=\/wp\/v2\/posts\/4344\/revisions"}],"predecessor-version":[{"id":25744,"href":"https:\/\/audioworx.transfunnel.co\/old\/index.php?rest_route=\/wp\/v2\/posts\/4344\/revisions\/25744"}],"wp:attachment":[{"href":"https:\/\/audioworx.transfunnel.co\/old\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4344"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/audioworx.transfunnel.co\/old\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4344"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/audioworx.transfunnel.co\/old\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4344"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/audioworx.transfunnel.co\/old\/index.php?rest_route=%2Fwp%2Fv2%2Fcoauthors&post=4344"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}