{"id":14801,"date":"2015-09-21T15:49:55","date_gmt":"2015-09-21T19:49:55","guid":{"rendered":"http:\/\/swling.com\/blog\/?p=14801"},"modified":"2015-09-21T15:56:35","modified_gmt":"2015-09-21T19:56:35","slug":"guest-post-joris-home-brew-si4835-based-receiver","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2015\/09\/guest-post-joris-home-brew-si4835-based-receiver\/","title":{"rendered":"Guest Post: Joris&#8217; home brew Si4835-based receiver"},"content":{"rendered":"<p><em>Many thanks to <em>Joris van Scheindelen (PE1KTH)<\/em>&#8211;an\u00a0SWLing Post contributor from the Netherlands&#8211;for the following guest post:<\/em><\/p>\n<hr \/>\n<h2>High Tech AM-FM DSP Receiver From<br \/>\n<a href=\"http:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/AM-FM-ontvanger-P3060601-e1442179065549.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-14802\" src=\"http:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/AM-FM-ontvanger-P3060601-e1442179065549.jpg\" alt=\"AM FM ontvanger P3060601\" width=\"650\" height=\"824\" \/><\/a><\/h2>\n<p>The old mode AM is still an interesting mode for amateur radio communication, also in amplitude CW.<\/p>\n<p>Building your receiver is not difficult and quite fun. The semiconductor industry makes interesting integrated receiver chips today that will be useful for an AM receiver. Not only for broadcast reception but also for amateur AM reception or as part of an AM transceiver.<\/p>\n<p>Silicon Labs also makes\u00a0Si4734\/35 receivers; these need a CPU to control the receiver, but are of interest for amateur use because the frequency can be tuned in 1 KHz steps and the audio channel bandwidth in 7 steps. There is no need for the transmitter to be on the receiving channel&#8230;<\/p>\n<h3>Si4835 AM-FM receiver<\/h3>\n<p>Looking for a small SW broadcast receiver design, and pocket size, I came to the excellent range of modern DSP receivers in a single chip from Slicon Labs.<\/p>\n<p>I made a test bed set up has been made for the Si4835 AM-FM receiver.<\/p>\n<p>The target specification was:<\/p>\n<ul>\n<li>minimal components,<\/li>\n<li>no micro-controller,<\/li>\n<li>low power,<\/li>\n<li>backlash free mechanical tuning,<\/li>\n<li>good sensitivity,<\/li>\n<li>earphone,<\/li>\n<li>robust housing,<\/li>\n<li>a short and small antenna system for outdoor use,<\/li>\n<li>and minimal controls.<\/li>\n<\/ul>\n<p>The Si4835 makes miniature design possible on a PCB (see photo Figure 1).<\/p>\n<p>The red Dip (band) switch was\u00a0replaced by a rotary switch in the final receiver design (Figure 4).<\/p>\n<p>The receiver power is minimal 2 x 1.2 = 2.4 volts or a one cell LI-ION accu.<br \/>\n5 volts is the maximum for the Si4835 chip; current consumption is 30 mA.<\/p>\n<div id=\"attachment_14902\" style=\"width: 531px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/Testbed.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-14902\" class=\" wp-image-14902\" src=\"http:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/Testbed.jpg\" alt=\"Fig 1. Testbed setup for the Si4835.\" width=\"521\" height=\"390\" srcset=\"https:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/Testbed.jpg 373w, https:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/Testbed-300x224.jpg 300w\" sizes=\"auto, (max-width: 521px) 100vw, 521px\" \/><\/a><p id=\"caption-attachment-14902\" class=\"wp-caption-text\">Fig 1. Testbed setup for the Si4835.<\/p><\/div>\n<p>The receiver has an RF pre-amplifier transistor and the LF amplifier is the TDA7050T.<br \/>\nAll receiver functions are in the chip; the schematic is very simple and can be built with minimal components (see schematic appnote AN555 Fig 2. below).<\/p>\n<p>Only an LF amplifier has to be added to complete the receiver.<\/p>\n<div id=\"attachment_14903\" style=\"width: 491px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/schematic.png\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-14903\" class=\"wp-image-14903 size-full\" src=\"http:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/schematic.png\" alt=\"schematic\" width=\"481\" height=\"639\" srcset=\"https:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/schematic.png 481w, https:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/schematic-226x300.png 226w\" sizes=\"auto, (max-width: 481px) 100vw, 481px\" \/><\/a><p id=\"caption-attachment-14903\" class=\"wp-caption-text\">Fig 2. Receiver schematic Si4835 in the AN555 application note.<\/p><\/div>\n<p>The Si4835 receiver has the following frequency bands&#8211;they are divided in sub bands 800 or 900 KHz wide (See Figure 3). The frequency step tuning is 10 kHz on AM, following the international broadcast raster standard.<\/p>\n<div id=\"attachment_14904\" style=\"width: 354px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/Figure3.png\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-14904\" class=\" wp-image-14904\" src=\"http:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/Figure3.png\" alt=\"Fig 3. Si4835 receiver sub bands.\" width=\"344\" height=\"407\" srcset=\"https:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/Figure3.png 255w, https:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/Figure3-254x300.png 254w\" sizes=\"auto, (max-width: 344px) 100vw, 344px\" \/><\/a><p id=\"caption-attachment-14904\" class=\"wp-caption-text\">Fig 3. Si4835 receiver sub bands.<\/p><\/div>\n<p>This means there are 80 or 90 receive channels in the sub bands and make finding the BC stations on the scale more easy. The 10 KHz scale steps are linear. The frequency stability is locked to the 32 kHz X-tal via the synthesizer so there is no frequency drift. The AM LF audio channel is 5 kHz wide set by the DSP filter. Volume control can be done width 2 up-down push switches or by a LF potentiometer..<\/p>\n<div id=\"attachment_14905\" style=\"width: 592px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/housing.png\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-14905\" class=\" wp-image-14905\" src=\"http:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/housing.png\" alt=\"Fig 4. The experimental pocket aluminium receiver housing on PCB2.\" width=\"582\" height=\"411\" srcset=\"https:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/housing.png 408w, https:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/housing-300x212.png 300w\" sizes=\"auto, (max-width: 582px) 100vw, 582px\" \/><\/a><p id=\"caption-attachment-14905\" class=\"wp-caption-text\">Fig 4. The experimental pocket aluminium receiver housing on PCB2.<\/p><\/div>\n<p><strong>Receiving results<\/strong><\/p>\n<p>I have been testing many hours and I am surprised about this little receiver.<\/p>\n<p>The receiving results are excellent on FM and AM and signals of 2 -3 uV are well received.<\/p>\n<p>Also the audio quality is good&#8211;especially on FM. As can be seen in the frequency table the 40 and 20 meter band are in the range. Clear AM phone amateur transmission has been received when the transmitter was tuned on the 10 kHz raster in 40 meter band on AM.<\/p>\n<p>Also AM modulated CW signals can be received bud not un-modulated carrier CW&#8211;they sound &#8220;plop&#8230;plop&#8221;.<\/p>\n<p>The 5 kHz wide LF channel is a bid too wide so many CW signals pass through the audio at the time, but if AM modulated that should not be a serious problem.<\/p>\n<p>The broadcast stations in the SW bands (when the daytime conditions are good) up to 20 MHz are good and strong.<\/p>\n<p><strong>Conclusions<\/strong><\/p>\n<p>The Si4835 receiver can be a fine broadcast receiver for outdoor work and if an AM transmitter is tuned in the 10 kHz raster this receiver can also used for amateur phone reception.<\/p>\n<p><strong>Addendum: The Si4734\/35 is a better amateur AM\u00a0Receiver<\/strong><\/p>\n<p>The Si4734 and Si4735 are a better receiver choice for amateur AM purpose because the frequency tuning can be done in 1 kHz steps. Also the BW of the LF channel can be adjusted to 1 kHz wide.<\/p>\n<p>In Fig 5. from the programming APP note you see the code 0X3102 AM CHANNEL_FILTER it is possible to adjust the audio width by sending this code to the Si4734\/35.<\/p>\n<div id=\"attachment_14906\" style=\"width: 471px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/table.png\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-14906\" class=\" wp-image-14906\" src=\"http:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/table.png\" alt=\"Fig 5. From the programming APP note\" width=\"461\" height=\"374\" srcset=\"https:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/table.png 307w, https:\/\/swling.com\/blog\/wp-content\/uploads\/2015\/09\/table-300x243.png 300w\" sizes=\"auto, (max-width: 461px) 100vw, 461px\" \/><\/a><p id=\"caption-attachment-14906\" class=\"wp-caption-text\">Fig 5. From the programming APP note<\/p><\/div>\n<p>The LF bandwidth can be set on 1, 1.8, 2.5, 2, 3, 4 and 6 kHz wide.<\/p>\n<p>This is excellent for modulated CW and AM phone discrimination in the audio channel.<\/p>\n<p>The disadvantage is the need of an CPU and LCD display, &#8220;away from a minimalistic design&#8221;.<\/p>\n<p>See also the note 1 and 2 improved 100 Hz rejection. See data sheet of the Si4734\/35.<\/p>\n<p>It look like that this receiver is a good receiver for building a modern AM-(AM)CW receiver or in a transceiver application. Tuning can be done digitally.<\/p>\n<p>Think about this receiver [and the Si4835 chipset] when you intent to build a high tech AM &#8211; T\/RX.<\/p>\n<p>73 &#8216; Joris van Scheindelen PE1KTH<\/p>\n<hr \/>\n<p><em><strong>What a fantastic home-brew receiver, Joris!<\/strong> I love the simple design of your receiver and the fact that it&#8217;s quite portable. \u00a0Thanks so much for sharing your notes and documentation.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Many thanks to Joris van Scheindelen (PE1KTH)&#8211;an\u00a0SWLing Post contributor from the Netherlands&#8211;for the following guest post: High Tech AM-FM DSP Receiver From The old mode AM is still an interesting mode for amateur radio communication, also in amplitude CW. Building your receiver is not difficult and quite fun. The semiconductor industry makes interesting integrated receiver [&hellip;]<\/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":[373,8,3781,3194,545,627,433,3,26,43],"tags":[2169,4239,4240,4238,4237,435,4236],"class_list":["post-14801","post","type-post","status-publish","format-standard","hentry","category-am","category-articles","category-fm","category-guest-posts","category-ham-radio","category-how-to","category-mediumwave","category-news","category-radios","category-shortwave-radio","tag-home-brew","tag-home-brew-receiver","tag-home-brew-si4835","tag-joris-van-scheindelen-pe1kth","tag-si4835","tag-silicon-labs","tag-silicon-labs-si4835"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pn3uc-3QJ","jetpack-related-posts":[{"id":1227,"url":"https:\/\/swling.com\/blog\/2011\/07\/silicon-labs-ships-one-billionth-dsp-radio-chip\/","url_meta":{"origin":14801,"position":0},"title":"Silicon Labs ships one billionth DSP radio chip","author":"Thomas","date":"July 3, 2011","format":false,"excerpt":"Silicon Labs, the chip manufacturer behind some of the best portable shortwave radios in the market (including Tecsun and Grundig) has sold its one billionth DSP radio chip. Silicon Labs has been one of the best things to happen to the portable shortwave market this century. Their DSP chips lower\u2026","rel":"","context":"In &quot;Manufacturers&quot;","block_context":{"text":"Manufacturers","link":"https:\/\/swling.com\/blog\/category\/manufacturers\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2011\/07\/silabslogo.gif?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":14182,"url":"https:\/\/swling.com\/blog\/2015\/07\/silicon-labs-dsp-chip-homebrew-receiver\/","url_meta":{"origin":14801,"position":1},"title":"Silicon Labs DSP chip homebrew receiver","author":"Thomas","date":"July 27, 2015","format":false,"excerpt":"The Silicon Labs Si4730 series DSP receiver chip powers many of the portable shortwave radios currently on the market. Manufacturers are not the only ones implementing the chip in receiver design, however; radio enthusiasts are too. I recently discovered this short video by a Japanese hobbyist who implemented the Si4734\u2026","rel":"","context":"In &quot;How To&quot;","block_context":{"text":"How To","link":"https:\/\/swling.com\/blog\/category\/how-to\/"},"img":{"alt_text":"DSP-Homebrew","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/07\/DSP-Homebrew.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/07\/DSP-Homebrew.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/07\/DSP-Homebrew.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2015\/07\/DSP-Homebrew.jpg?resize=700%2C400 2x"},"classes":[]},{"id":2296,"url":"https:\/\/swling.com\/blog\/2011\/12\/silabs-brings-shortwave-to-car-radios\/","url_meta":{"origin":14801,"position":2},"title":"SiLabs brings shortwave to car radios","author":"Thomas","date":"December 3, 2011","format":false,"excerpt":"Silicon Labs, a manufacture of DSP (Digital Signal Processing) chips that are in many of the shortwave radios we feature here on SWLing.com, is now taking their technology to car radios. They have announced the\u00a0Si476x chip family which features\u00a0AM\/FM, longwave, shortwave (SW), NOAA weather band, FM RDS decoding and AM\/FM\u2026","rel":"","context":"In &quot;Manufacturers&quot;","block_context":{"text":"Manufacturers","link":"https:\/\/swling.com\/blog\/category\/manufacturers\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2011\/07\/silabslogo.gif?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":38766,"url":"https:\/\/swling.com\/blog\/2019\/07\/new-silicon-labs-automotive-radio-tuners-support-drm-and-built-on-sdr-friendly-technology\/","url_meta":{"origin":14801,"position":3},"title":"New Silicon Labs automotive radio tuners support DRM and built on &#8220;SDR-friendly technology&#8221;","author":"Thomas","date":"July 31, 2019","format":false,"excerpt":"Many thanks to a number of SWLing Post readers who shared this latest press release from Silicon Labs. This is certainly a major upgrade to the Silicon Labs line of tuners\/DSP chips. Native Digital Radio Mondiale (DRM) support will, no doubt, meet the needs of car manufactures in countries (like\u2026","rel":"","context":"In &quot;Digital Modes&quot;","block_context":{"text":"Digital Modes","link":"https:\/\/swling.com\/blog\/category\/digital-modes\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2019\/07\/Silicon-Labs.jpeg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":10157,"url":"https:\/\/swling.com\/blog\/2014\/07\/china-radio-international-warbling-on-daves-home-brew-receiver\/","url_meta":{"origin":14801,"position":4},"title":"China Radio International warbling on Dave&#8217;s home brew receiver","author":"Thomas","date":"July 13, 2014","format":false,"excerpt":"My buddy and SWLing Post reader, Dave Richards (AA7EE), wrote several weeks ago\u00a0with an interesting comment: \"I was just now \u00a0tuning around the 31M band on a [regenerative receiver]\u00a0that I am putting the finishing touches on, and noticed that the audio from China Radio International on 9790KHz was not only\u2026","rel":"","context":"In &quot;International Broadcasting&quot;","block_context":{"text":"International Broadcasting","link":"https:\/\/swling.com\/blog\/category\/international-broadcasting\/"},"img":{"alt_text":"IMG_7078","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2014\/07\/IMG_7078.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2014\/07\/IMG_7078.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2014\/07\/IMG_7078.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2014\/07\/IMG_7078.jpg?resize=700%2C400 2x"},"classes":[]},{"id":1420,"url":"https:\/\/swling.com\/blog\/2011\/07\/silicon-labs-si4734-dsp-shortwave-radios\/","url_meta":{"origin":14801,"position":5},"title":"Silicon Labs Si4734 DSP-based shortwave radios","author":"Thomas","date":"July 23, 2011","format":false,"excerpt":"I have gone through our Shortwave Radio Index (SWRI) and tagged every portable radio that is based on the Silicon Labs Si4734 DSP chipset. The Si4734 has been one of the biggest innovations to happen to portable receivers in recent years. When implemented well into a receiver design, the Si4734\u2026","rel":"","context":"In &quot;Radios&quot;","block_context":{"text":"Radios","link":"https:\/\/swling.com\/blog\/category\/radios\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/swling.com\/blog\/wp-content\/uploads\/2011\/07\/SI4735-circuits-300x194.jpg?resize=350%2C200","width":350,"height":200},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/14801","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=14801"}],"version-history":[{"count":0,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/posts\/14801\/revisions"}],"wp:attachment":[{"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/media?parent=14801"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/categories?post=14801"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/swling.com\/blog\/wp-json\/wp\/v2\/tags?post=14801"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}