How tuners work?  - Page 1
Forum section: electronics / general

author: Jane
author_rank: Frequent Contributor
timestamp: September 27, 2012, 07:29:29 pm
content: Is there any tutorial/description from which I can understand how tuners( preferably satellite tuners) work?E.g.BSBE2 Alps tuner series use various signals, in datasheet marked as+B1 (RF-AMP)+B2 (DCR)+B3 (I/F)+B4 (CORE)etc.and I do not know what they are for.Thanks for the reply.

author: amvakar
author_rank: Contributor
timestamp: September 27, 2012, 08:09:27 pm
content: This is a highly-integrated device that is supposed to do everything for you. Plug it in correctly and any microcontroller will be able to tune it and configure it and receive metadata. I've used similar devices to build radios and cell modems without doing much RF work.The problem that you're going to have with this manufacturer is that they don't give out any of the actual specifications you'd need to plug it in, let alone configure it and process the data it outputs. You'll need to contact them, sign an NDA (in all probability), and get the real datasheet before you can do anything.

author: Unknown
author_rank: Unknown
timestamp: September 27, 2012, 08:58:00 pm
content: Hi, no doubt you have the data sheet ? if not see this site URL:http://www.datasheetdir.com/BSBE2+download+B indicate power supplies to internal stages of the tuner, however this tuner like all units now days are I-2-Cchip-set controled... so all tuning requires data input Read-Write.Also this might help, interface chip but, require more detail for the tuner connections URL:http://pdf1.alldatasheet.com/datasheet-pdf/view/113715/STMICROELECTRONICS/STB0899.htmland here is some general info for fault finding, for the slot pins:http://www.articleclick.com/Article/How-to-Find-Out-and-Repair-the-Glitches-on-Tuner-Component-Palette-of-DM800HD/1526346Your problem is to find a circuit for the Dream Box or other receiver that use this Alps tuner, you can then back engineer the pin-outs and maybe, get a better understanding of their use.

author: Jane
author_rank: Frequent Contributor
timestamp: September 28, 2012, 07:25:34 am
content: Thank you for the reply.I checkedhttp://www.articleclick.com/Article/How-to-Find-Out-and-Repair-the-Glitches-on-Tuner-Component-Palette-of-DM800HD/1526346butdo not understand what is meant by" 12-pin moderate frequency output ".Do you know that? And what ismoderate?Neither I do not understand what is meant byB4 pin in the sentence like thisYou can test the B4 pin of adapt plug to make sure. If the pin has a voltage of 0.1 volt ...I would say it is pin 17th of tuner that is +B4 (CORE), seehttp://www.datasheetdir.com/BSBE2+downloadbut I have here a tuner that does NOT have 16/21 volt on 19th pin of LNBP21 (LJ501)and yet there is NOT neither 0.1V nor 0.4V but 1,2V(that should be the correct value for 17th pin).But of course tuner does not work, because of the missing 16/21 volt on 19th pin of LNBP21 (LJ501).Do you have any answers to those my questions?Thank you for help

author: Bored@Work
author_rank: Super Contributor
timestamp: September 28, 2012, 06:46:08 pm
content: Sounds like the article is machine-translated or not written by a native speaker. I wouldn't really bother with such a description.12-pin maybe means pin 12. Moderate maybe means modulate, or they mean the IF output.B4 might be the silkscreen marking for the power adapter / wall wart. It sounds like when there is a short on the power rail the power supply is going into current-limiting, resulting in only 0.1 V on the rail.

author: poptones
author_rank: Frequent Contributor
timestamp: September 28, 2012, 06:49:01 pm
content: Moderate doesn't mean modulate, but it does meanintermediate. Sounds like IF output.

author: Unknown
author_rank: Unknown
timestamp: September 28, 2012, 07:55:19 pm
content: I think you might consider purchasing a service book for satellite repairs... the terms you require will most likely be given, regarding the pin-outs to a description of there applied use; on-line information is almost absent to find, that's why I recommend you obtain a service manual for the receiver in question for this tuner unit, then back-engineer the pin-outs, to there used location; e.g. +B = power supplies and so-on.URL: for a service book is here if you think it's worth the money for your needs...http://www.satcure.co.uk/drxtuner.htmFurther, here is a pdf for a Sony satellite receiver, it's not using the Alps tuner but, will give you the idea about back-engineering from a schematic drawing, to find out about the pin connections... see URL look at page 21.http://www.2150.com/directv/files/sony_sat_t60_sm.pdf