The DTV industry found out pre-echoes of strength could be much longer than 4 microsec. -- Maybe up to 30 microsec. Then there is the repeat problem with FIR filtering. Also, channel repeaters can make bad pre-echoes in the transition region. Too bad legacy receivers kept us from going to triple-PN1023 field sync, which handles 90 microsec.echo range easy as duck soup. Al ----- Original Message ----- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx> To: <opendtv@xxxxxxxxxxxxx> Sent: Friday, July 07, 2006 6:14 PM Subject: [opendtv] Re: Patent application on 8-VSB equalizer > Al Limberg wrote: > > > U.S. patent No. 6,081,301, titled "DTV CIRCUITRY FOR > > MEASURING MULTIPATH DISTORTION BASED ON GHOSTING OF > > DATA SEGMENT SYNCHRONIZING SIGNALS", issued to me 27 > > June 2000 and is assigned to Samsung Electronics. > > Well, sonuvagun, it says close to the same thing as that later patent > application. > > One thing you explain in there is how the middle PN63 sequence can be > used to detect pre-echoes to -53.7 usec. But then you minimize the > importance of this, based on measurements which, at the time, indicated > that anything more than -4 usec was going to be rare. > > If matched filters in the new tuner designs don't take care of much > greater pre-ghost than 4 usec, it would seem to me that using this > middle PN63 technique in equalizers would be ideal for fairly widely > spaced unsynchronized on-channel repeaters. Because in this case, > there's no issue with dynamic multipath. The pre-ghosts are steady as > can be. > > Bert > > > ---------------------------------------------------------------------- > 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 FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.