{"id":14331,"date":"2015-08-19T07:46:47","date_gmt":"2015-08-19T11:46:47","guid":{"rendered":"http:\/\/swling.com\/blog\/?p=14331"},"modified":"2015-08-19T07:46:47","modified_gmt":"2015-08-19T11:46:47","slug":"dsp-noise-may-come-from-clock-and-data-line-harmonics","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2015\/08\/dsp-noise-may-come-from-clock-and-data-line-harmonics\/","title":{"rendered":"DSP noise may come from clock and data line harmonics"},"content":{"rendered":"

\"ATS-405-9580kHz\"<\/a><\/p>\n

In response to our review of the Sangean ATS-405<\/a>–which noted DSP noises on 800 and 1600 kHz–SWLing Post<\/em> reader, Steve Yothment, comments:<\/p>\n

“Yes, modern radios usually have a micro communicating with the DSP IC through I2C communications.<\/p>\n

The inter-IC communications includes a clock and data line. The clock for I2C is typically 400 kHz nowadays. Harmonics from this clock line are probably the source of the interference.<\/p>\n

The manufacturer should have designed the product to ensure that this interference does not occur. It may be that they resolved it at one time but with limited manufacturing quality and component substitutions that often occur in mass production, the problem is occurring now even though it may have looked OK earlier in development. At least, that is my experience with such things. (I used to design car radios for the Panasonic Company.)<\/p>\n

You can learn more about the I2C bus at https:\/\/en.wikipedia.org\/wiki\/I%C2%B2C<\/a>.<\/p><\/blockquote>\n

Many thanks for your comments, Steve! I recall a similar metronomic sound on another DSP-based radio, but can’t remember which model. I need to dig through my reviews as I’m sure I noted this. I believe checking 400, 800 and 1600 kHz will become a standard checklist item when I review DSP-based radios.<\/p>\n","protected":false},"excerpt":{"rendered":"

In response to our review of the Sangean ATS-405–which noted DSP noises on 800 and 1600 kHz–SWLing Post reader, Steve Yothment, comments: “Yes, modern radios usually have a micro communicating with the DSP IC through I2C communications. The inter-IC communications includes a clock and data line. The clock for I2C is typically 400 kHz nowadays. […]<\/p>\n","protected":false},"author":15,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[373,3,26,43],"tags":[3927,4127,4060,4059,3926,3162],"class_list":["post-14331","post","type-post","status-publish","format-standard","hentry","category-am","category-news","category-radios","category-shortwave-radio","tag-ats-405","tag-clock-harmonics","tag-dsp-birdies","tag-dsp-ic","tag-sangean-ats-405","tag-steve-yothment"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pn3uc-3J9","jetpack-related-posts":[{"id":13827,"url":"https:\/\/swling.com\/blog\/2015\/06\/the-new-sangean-ats-405-shortwave-portable\/","url_meta":{"origin":14331,"position":0},"title":"The new Sangean ATS-405 shortwave portable","author":"Thomas","date":"June 25, 2015","format":false,"excerpt":"[UPDATE: Click here for a full review of the Sangean ATS-405] Many thanks to SWLing Post contributor, Aaron Hyde, who reports that Sangean has a new travel radio on the market: the Sangean ATS-405. Aaron writes: \"While looking around the internet today, I came across a new DSP shortwave radio\u2026","rel":"","context":"In "New Products"","block_context":{"text":"New Products","link":"https:\/\/swling.com\/blog\/category\/new-products\/"},"img":{"alt_text":"Sangean-ATS-405","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/06\/Sangean-ATS-405-1024x793.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/06\/Sangean-ATS-405-1024x793.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/06\/Sangean-ATS-405-1024x793.jpg?resize=525%2C300 1.5x"},"classes":[]},{"id":14155,"url":"https:\/\/swling.com\/blog\/2015\/07\/initial-review-of-the-sangean-ats-405\/","url_meta":{"origin":14331,"position":1},"title":"Initial review of the Sangean ATS-405","author":"Thomas","date":"July 25, 2015","format":false,"excerpt":"Just last week, I received the new Sangean ATS-405\u00a0on loan from Universal Radio. Though I've only had the radio for a week, I thought I'd share a few un-boxing photos (by request) and my initial impressions\/review of this radio. Unboxing The ATS-405 comes with a thick owner's manual (in five\u2026","rel":"","context":"In "AM"","block_context":{"text":"AM","link":"https:\/\/swling.com\/blog\/category\/am\/"},"img":{"alt_text":"Sangean-ATS-405-Box","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/07\/Sangean-ATS-405-Box.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/07\/Sangean-ATS-405-Box.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/07\/Sangean-ATS-405-Box.jpg?resize=525%2C300 1.5x"},"classes":[]},{"id":14206,"url":"https:\/\/swling.com\/blog\/2015\/07\/sangean-ats-405-review-update\/","url_meta":{"origin":14331,"position":2},"title":"Update: Sangean ATS-405 initial review","author":"Thomas","date":"July 28, 2015","format":false,"excerpt":"After publishing my initial review of the Sangean ATS-405, I received feedback from several ATS-405 owners (via comments and email--thank you!) who do not have the internally-generated DSP \"birdies\" that plague my receiver on 800 and 1600 kHz AM. I strongly suspect my ATS-405 has a manufacturing defect of some\u2026","rel":"","context":"In "News"","block_context":{"text":"News","link":"https:\/\/swling.com\/blog\/category\/news\/"},"img":{"alt_text":"Sangean-ATS-405","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/07\/Sangean-ATS-4051.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/07\/Sangean-ATS-4051.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/07\/Sangean-ATS-4051.jpg?resize=525%2C300 1.5x"},"classes":[]},{"id":14308,"url":"https:\/\/swling.com\/blog\/2015\/08\/update-sangean-ats-405-review\/","url_meta":{"origin":14331,"position":3},"title":"Update: Sangean ATS-405 review","author":"Thomas","date":"August 11, 2015","format":false,"excerpt":"After publishing my initial review of the Sangean ATS-405\u00a0on July 25, I\u00a0contacted Sangean and requested a sample radio for comparison purposes. Back story: \u00a0there were some receiver performance issues that I suspected\u00a0may have been tied to my particular ATS-405 unit. Sangean\u00a0kindly dispatched another ATS-405 which I received last\u00a0week. The following\u2026","rel":"","context":"In "AM"","block_context":{"text":"AM","link":"https:\/\/swling.com\/blog\/category\/am\/"},"img":{"alt_text":"Sangean-ATS-405","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/07\/Sangean-ATS-4051.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/07\/Sangean-ATS-4051.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/07\/Sangean-ATS-4051.jpg?resize=525%2C300 1.5x"},"classes":[]},{"id":40850,"url":"https:\/\/swling.com\/blog\/2019\/11\/sangean-dt-140-sr-32-two-new-sangean-am-fm-radios\/","url_meta":{"origin":14331,"position":4},"title":"Sangean DT-140 & SR-32: New Sangean AM\/FM radios","author":"Thomas","date":"November 29, 2019","format":false,"excerpt":"Many thanks to SWLing Post contributor, Michael Schuster, who writes: Attached image [above] is extracted from a PDF of the 2020 catalog, it shows the upcoming Sangean DT-140 and SR-32. Wondering if the SR-32 (from the almost-defunct \"slide rule\" series) uses DSP-as-analog tuning like its larger sibling with speaker. Thanks\u2026","rel":"","context":"In "AM"","block_context":{"text":"AM","link":"https:\/\/swling.com\/blog\/category\/am\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/11\/Sangean-DT-140-and-SR-32-1024x826.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/11\/Sangean-DT-140-and-SR-32-1024x826.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/11\/Sangean-DT-140-and-SR-32-1024x826.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":35957,"url":"https:\/\/swling.com\/blog\/2019\/02\/radiwow-r-108-tracking-down-mediumwave-am-birdies\/","url_meta":{"origin":14331,"position":5},"title":"Radiwow R-108: Tracking down mediumwave\/AM birdies","author":"Thomas","date":"February 7, 2019","format":false,"excerpt":"As I mentioned in a post yesterday, I've been spending time with the Radiwow R-108 in an effort to give it a proper evaluation. One quirk that has been a little hard to pin down is the occasional DSP birdie on the mediumwave band. [BTW: A \"birdie\" an unwanted internally-generated\u2026","rel":"","context":"In "AM"","block_context":{"text":"AM","link":"https:\/\/swling.com\/blog\/category\/am\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/02\/Radiwow-R-108-1600-kHz-AM-Dial-1024x701.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/02\/Radiwow-R-108-1600-kHz-AM-Dial-1024x701.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/02\/Radiwow-R-108-1600-kHz-AM-Dial-1024x701.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/14331","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/users\/15"}],"replies":[{"embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/comments?post=14331"}],"version-history":[{"count":0,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/14331\/revisions"}],"wp:attachment":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/media?parent=14331"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/categories?post=14331"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/tags?post=14331"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}