On Oct 10, 2012, at 5:05 PM, Magnus Danielson <[email protected]> wrote:
> On 10/10/2012 01:09 PM, Bob Camp wrote: >> Hi >> >> …. and if we have to go to something more exotic than simple two pole >> filters the group delay (and it's variation) has got to go up. > > Yes and no. > > As you add pole-pairs, their group delay contributions adds up. However, as > you add pole-pairs you also get a pair of zeros for the slopes (typically > located in 0 and infinity for band-pass response) and you can back off > considerably in Q values, and aim for maximum flat group delay in the > pass-band. See the difference between the amplifiers in the article. > Unless you need to go to something with sharp skirts. Then you are likely to start from a fairly high Q lowpass prototype and add a delay equalizer. Starts to add up pretty fast... >> At least some of the HP splitters have RF filters in them. The same is true >> of GPS receivers. A receiver or splitter in the attic will have many of the >> same group delay issues as an antenna. I know, who would put one in the >> attic. Just how warm does that rack get as the air-conditioning cycles and >> the vents clog up? > > The filters do add up, true. But then one should also recall the cable in the > total, as covered by others. indeed, but it's a bit tough to keep the cable all indoors. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
