Return-Path: Received: from mtain-de11.r1000.mx.aol.com (mtain-de11.r1000.mx.aol.com [172.29.64.211]) by air-dc06.mail.aol.com (v128.3) with ESMTP id MAILINDC061-86024bd6234e32; Mon, 26 Apr 2010 19:35:42 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-de11.r1000.mx.aol.com (Internet Inbound) with ESMTP id CEAF4380000AA; Mon, 26 Apr 2010 19:35:40 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1O6Xoh-0003kd-HT for rs_out_1@blacksheep.org; Tue, 27 Apr 2010 00:34:19 +0100 Received: from [193.82.59.130] (helo=relay2.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1O6Xog-0003kU-Tz for rsgb_lf_group@blacksheep.org; Tue, 27 Apr 2010 00:34:18 +0100 Received: from cmsout02.mbox.net ([165.212.64.32]) by relay2.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1O6Xoe-0007ov-6e for rsgb_lf_group@blacksheep.org; Tue, 27 Apr 2010 00:34:18 +0100 Received: from cmsout02.mbox.net (co02-lo [127.0.0.1]) by cmsout02.mbox.net (Postfix) with ESMTP id 9C1AD134498 for ; Mon, 26 Apr 2010 23:32:30 +0000 (GMT) Received: from cmsapps02.cms.usa.net [165.212.11.138] by cmsout02.mbox.net via smtad (C8.MAIN.3.61T) with ESMTP id XID645oDZXGE1415X02; Mon, 26 Apr 2010 23:32:30 -0000 X-USANET-Source: 165.212.11.138 IN dibene@usa.net cmsapps02.cms.usa.net X-USANET-MsgId: XID645oDZXGE1415X02 Received: from [192.168.1.4] [151.47.216.26] by cmsapps02.cms.usa.net (ESMTPA/dibene@usa.net) via mtad (C8.MAIN.3.53P) with ESMTPA id 208oDZXGC2016M38; Mon, 26 Apr 2010 23:32:28 -0000 X-USANET-Auth: 151.47.216.26 AUTH dibene@usa.net [192.168.1.4] Message-ID: <4BD62289.6040703@usa.net> Date: Tue, 27 Apr 2010 01:32:25 +0200 From: Alberto di Bene User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.9) Gecko/20100317 Thunderbird/3.0.4 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4EB4F8217FCC42CAB07AE666A6AB07B8@AGB> <4BD5F358.8040508@freenet.de> <4BD6147C.7080201@usa.net> In-Reply-To: X-Enigmail-Version: 1.0.1 Z-USANET-MsgId: XID208oDZXGC2016X38 X-Spam-Score: 0.8 (/) X-Spam-Report: autolearn=disabled,AWL=-0.629,HTML_MESSAGE=0.001,MIME_HTML_ONLY=0.001,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: Probably not a new question... Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.5 required=5.0 tests=HTML_30_40,HTML_MESSAGE, HTML_TITLE_EMPTY,MIME_HTML_ONLY 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-aol-global-disposition: G x-aol-sid: 3039ac1d40d34bd6234c5473 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) On 4/27/2010 12:50 AM, Daniele Tincani wrote:

Hi Alberto,

thank you very much for clarification. I was misled by the softrock example :-)

Anyway, a doubt persists...I read on the frontpanel of the R&S SDR that it is a "digital wideband receiver"...Well, in my "prejudice", "wideband" does not match with "high-quality", unless the radio contain several different "narrow band" receivers. Is this (apparent) conflict solved at the digital signal processing level?

Regards

D

HI Daniele,

yes, it is a prejudice, as a matter of facts.... why "wideband" should be not compatible with "high quality" ? This stems probably from the
old analog world, where you had to face conflicting requirements... in a SDR, "wideband" can mean e.g. that an ADC does directly sample the
incoming RF spectrum at a rate of 150 MHz (there are ADCs capable of this), thus providing information up to the Nyquist frequency of 75 MHz.
Then you have just numbers, and with numbers you can perform miracles, if correctly handled (ask to an accountant, if you don't believe me... :-)

When you have the digitized stream of numbers that represents the 75 MHz chunk of spectrum, you can, if you need to, analyze those
75 MHz with a resolution of 0.001 Hz, yes, one millihertz... changing on-the-fly where that millihertz is placed on the spectrum, or even its
bandwidth... try that with an old, analog "high quality" radio.... :-)

Of course, you need both the mathematical background in digital signal processing and coding ability to do that, and these are skills not very
familiar to analog RF engineers that hence look suspiciously to the new world of SDRs. But this does not mean that it can't be done....

73 Alberto I2PHD