Although I am not an engineer, my understanding is that group delay is the phase shifting signals experience as they go through circuits such as filters. A non linear response as you go across the filter bandwidth means that different tones will be affected differently and cause smearing of the signal. For example, in a passband filter you can have several ms delay in parts of the filter and almost no delay in other parts of the passband. I guess you can consider it also a non-linear phase shift across the passband. However, I think that the ionosphere is even worse than most amateur equipment.
Here is a URL that helps explain it: http://www.rfengineer.cc/pdf/group_delay.pdf 73, Rick, KV9U DuBose Walt Civ AETC CONS/LGCA wrote: >Rick, > >Please explain "group delays". I am unfamilar with that term in reference to >transmitting equipment. > >Walt/K5YFW > >-----Original Message----- >From: [email protected] [mailto:[EMAIL PROTECTED] >Sent: Wednesday, September 20, 2006 4:28 PM > >[stuff deleted] > >Another thing that I came across in my web searching was that amateur >equipment generally has group delays that make it difficult to even >employ some of the modems we have been discussing. > >I wonder if any of the modem experts might comment on that. > >73, > >Rick, KV9U > > > > Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/digitalradio/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
