In 1998 the first COFDM box, the Philips 6370, had to have an attenuator = (6-9dB) fitted in line to make it work in the presence of very strong adj= acent channel analogue signals. The design of that receiver did not have = sufficient selectivity. Experience from that unit, SEVEN YEARS AGO, was = factored straight into the design of COFDM boxes. Nowadays even the el ch= eapo COFDM boxes have fantastic receiver RF performance because they have= to. And there is a further development which will seriously impact DVB-T= : because of the coming of DVB-H it is necessary to have a system on a ch= ip with full digital RF eg Texas Instruments forthcoming DVB-H chip. Thes= e chips will have outstanding RF performance because they have to in the = mobile environment. DVB-H is backwards compatible with DVB-T. Several IC = vendors have told me that expect only to be making DVB-H chips in a coupl= e of years time: so DVB-T receivers will benefit from this digital miniat= urisation. Full details are on the TI and Dibcom web site. So now we have= ATSC trying to fix receiver selectivity problems which were fixed in sec= ond generation COFDM boxes: maybe by generation 12 they will catch up wit= h COFDM year 2000 receiver performance. A sorry saga continues.. Kind Regards, Dermot nOlan -------------Forwarded Message----------------- From: INTERNET:opendtv@xxxxxxxxxxxxx, INTERNET:opendtv@xxxxxxxxxxxxx To: , INTERNET:opendtv@xxxxxxxxxxxxx = Date: 16/03/105 18:07 PM RE: [opendtv] Re: 5th generation Test = Doug wrote: > It's now time to try the el-cheapo 5th generation box with > a really good single-channel filter (Blonder-Tongue?) > in front of it for the difficult channels. If it really is the > front end, that should make it work. Bob, this is very good advice from Doug. Hammett & Edison's use of a prefilter turned the early poor performing RCA TC100(?) receiver into a moderately good performer in their San Francisco tests. Also, Sinclair used a similar technique on the "failed" COFDM monitor/receiver used in the MSTV tests, turning it into a stellar performer. Unfortunately, MSTV/NAB didn't want their results confused by fact and summarily rejected Sinclair's findings. As I recall, that filter was about 40 MHz wide (about six channels). Without the proper use of selectivity, a DTV receiver doesn't stand much of a chance in congested RF environs. ----- Original Message ----- = From: "Doug McDonald" <mcdonald@xxxxxxxxxxxx> To: <opendtv@xxxxxxxxxxxxx> Sent: Tuesday, March 15, 2005 9:29 AM Subject: [opendtv] Re: 5th generation Test > Manfredi, Albert E wrote: > >> Dale Kelly wrote: >> >> >>>As I previously suggested might be the case, it appears >>>that Zenith utilized a specially designed RF front end >>>in the receiver used for the 5th Gen demonstrations - >>>possibly never to be seen again in a consumer product. > > > It's now time to try the el-cheapo 5th generation box with > a really really good single-channel filter (Blonder-Tongue?) > in front of it for the difficult channels. If it really is the > front end, that should make it work. It could also > be something else, like the chip allows different amounts of > external memory, or uses aid from the main box CPU, and > these were lacking in teh cheapo box. > > Doug McDonald > > > ---------------------------------------------------------------------- > You can UNSUBSCRIBE from the OpenDTV list in two ways: > > - Using the UNSUBSCRIBE command in your user configuration settings at = > FreeLists.org > > - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word = > unsubscribe in the subject line. > > = = = ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at Fr= eeLists.org = - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word un= subscribe in the subject line. ----------------------- Internet Header -------------------------------- Sender: opendtv-bounce@xxxxxxxxxxxxx Received: from turing.freelists.org (freelists-180.iquest.net [206.53.239= .180]) by siaag2aa.compuserve.com (8.12.11/8.12.7/SUN-2.17) with ESMTP id j2GI6= qpC019690 for <dmenolan@xxxxxxxxxxxxxx>; Wed, 16 Mar 2005 13:06:53 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP = id 6F55C8716F; Wed, 16 Mar 2005 13:07:30 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 26114-10; Wed, 16 Mar 2005 13:07:30 -0500 (EST) Received: from turing (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP = id E3095870BE; Wed, 16 Mar 2005 13:07:29 -0500 (EST) Received: with ECARTIS (v1.0.0; list opendtv); Wed, 16 Mar 2005 13:07:02 = -0500 (EST) X-Original-To: opendtv@xxxxxxxxxxxxx Delivered-To: opendtv@xxxxxxxxxxxxx Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP = id 8AC7F871A3 for <opendtv@xxxxxxxxxxxxx>; Wed, 16 Mar 2005 13:07:02 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 25971-10 for <opendtv@xxxxxxxxxxxxx>; Wed, 16 Mar 2005 13:07:02 -0500 (EST) Received: from vms048pub.verizon.net (vms048pub.verizon.net [206.46.252.4= 8]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP = id 64C98870BE for <opendtv@xxxxxxxxxxxxx>; Wed, 16 Mar 2005 13:07:02 -0500 (EST) Received: from your1530308f1e ([4.35.218.175]) by vms048.mailsrvcs.net (Sun Java System Messaging Server 6.2 HotFix 0.0= 4 (built Dec 24 2004)) with ESMTPA id <0IDG00EFJIBOHCS0@xxxxxxxxxxxxxxxxxx= et> for opendtv@xxxxxxxxxxxxx; Wed, 16 Mar 2005 12:07:02 -0600 (CST) Date: Wed, 16 Mar 2005 10:07:02 -0800 From: "Dale Kelly" <dalekelly@xxxxxxxxxxx> Subject: [opendtv] Re: 5th generation Test To: <opendtv@xxxxxxxxxxxxx> Message-id: <001101c52a52$f4a3fd80$afda2304@your1530308f1e> MIME-version: 1.0 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Mailer: Microsoft Outlook Express 6.00.2900.2180 Content-type: text/plain; charset=3Diso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-priority: Normal References: = <EF40C42ACAB7A649B2EAE70C19B6CD6E037C38D5@xxxxxxxxxxxxxxxxxxxxxxxxxxx> <42371B66.8050101@xxxxxxxxxxxx> X-Virus-Scanned: clamd / ClamAV version 0.75.1, clamav-milter version 0.7= 5c on siaag2aa.compuserve.com X-Virus-Scanned: by amavisd-new-20030616-p9 (Debian) at avenirtech.net X-archive-position: 6861 X-ecartis-version: Ecartis v1.0.0 Sender: opendtv-bounce@xxxxxxxxxxxxx Errors-To: opendtv-bounce@xxxxxxxxxxxxx X-original-sender: dalekelly@xxxxxxxxxxx Precedence: normal Reply-To: opendtv@xxxxxxxxxxxxx X-list: opendtv X-Virus-Scanned: by amavisd-new-20030616-p9 (Debian) at avenirtech.net X-Virus-Status: Clean ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.