Return-Path: Received: (qmail 88962 invoked from network); 24 Feb 2005 19:55:38 -0000 Received: from unknown (HELO ptb-spamcore01.plus.net) (192.168.71.1) by ptb-mailstore02.plus.net with SMTP; 24 Feb 2005 19:55:38 -0000 Received: from mailnull by ptb-spamcore01.plus.net with spamcore-l-b (Exim 4.32; FreeBSD) id 1D4P68-0001ec-Qg for dave@picks.force9.co.uk; Thu, 24 Feb 2005 19:56:34 +0000 Received: from [192.168.67.2] (helo=ptb-mxcore02.plus.net) by ptb-spamcore01.plus.net with esmtp (Exim 4.32; FreeBSD) id 1D4P68-0001eZ-Ms for dave@picks.force9.co.uk; Thu, 24 Feb 2005 19:56:32 +0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore02.plus.net with esmtp (Exim) id 1D4P5D-000DeR-Tu for dave@picks.force9.co.uk; Thu, 24 Feb 2005 19:55:35 +0000 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1D4P1z-00018F-Of for rs_out_1@blacksheep.org; Thu, 24 Feb 2005 19:52:15 +0000 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1D4P1x-00017a-6d for rsgb_lf_group@blacksheep.org; Thu, 24 Feb 2005 19:52:13 +0000 Received: from cmsout02.mbox.net ([165.212.64.32]) by relay.thorcom.net with esmtp (Exim 4.43) id 1D4P1s-0002By-Uy for rsgb_lf_group@blacksheep.org; Thu, 24 Feb 2005 19:52:13 +0000 Received: from cmsout02.mbox.net (cmsout02.mbox.net [165.212.64.32]) by cmsout02.mbox.net (Postfix) with ESMTP id 5BFD04C83E for ; Thu, 24 Feb 2005 19:51:49 +0000 (GMT) Received: from cmsapps02.cms.usa.net [165.212.11.138] by cmsout02.mbox.net via smtad (C8.MAIN.3.21U); Thu, 24 Feb 2005 19:51:49 GMT X-USANET-Source: 165.212.11.138 IN dibene@usa.net cmsapps02.cms.usa.net X-USANET-MsgId: XID271JBXTzx1169X02 Received: from [192.168.0.2] [151.41.147.203] by cmsapps02.cms.usa.net (ASMTP/dibene@usa.net) via mtad (C8.MAIN.3.21E) with ESMTP id 353JBXTzv0227M38; Thu, 24 Feb 2005 19:51:47 GMT X-USANET-Auth: 151.41.147.203 AUTH dibene@usa.net [192.168.0.2] Message-ID: <421E3055.90404@usa.net> Date: Thu, 24 Feb 2005 20:51:49 +0100 From: Alberto di Bene User-Agent: Mozilla Thunderbird 1.0 (Windows/20041206) X-Accept-Language: en-us, en MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: In-Reply-To: X-Enigmail-Version: 0.89.5.0 X-Enigmail-Supports: pgp-inline, pgp-mime Z-USANET-MsgId: XID353JBXTzW0227X38 X-SPF-Result: relay.thorcom.net: 165.212.64.32 is neither permitted nor denied by domain of usa.net X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=failed,none Subject: LF: Re: How many bits ? (was :Off Topic Ft101zd) Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Spam-Filtered: by PlusNet SpamCORE (v3.00) Alexander S. Yurkov wrote: >Certanly if this 10uV signal is the only signal in ADC input then >ADC gives zero code only. Nothing more. But we can add a noise with >spectrum out of signal spectrum (so called 'dithering'). Then signals >can be digitized by the ADC. Added noise can be canceled by digital >filtering then. > > Alex, I am familiar with the concept of noise dithering, but IMHO you can apply it only when the added noise is spread all over the digitization bandwidth. In such a case you can gain many bits of resolution doing a decimation after the oversampling. But what you are saying is that I can put two pure sine signals at e.g. 1 MHz, one of them of 1V amplitude, and the other of 1uV amplitude, separated by, let's say, 1 kHz, digitize them with a 16-bit, 100 MHz ADC and then, by simply decimating (low pass + subsampling) and applying a post-decimation filter, I can resolve them ? I don't think it is possible, but, then, I have been wrong other times... 73 Alberto I2PHD