Hi It would be a very unusual synthesizer back in 1955. Some sort of carrier recovery / IF application seems more likely.
Bob > On Mar 7, 2016, at 6:30 AM, Tim Shoppa <tsho...@gmail.com> wrote: > > For crystal lattice and especially ladder filters, a Q of 10,000 is very > much in the "sweet spot" if you are starting off with bare crystals in the > Q=50,000 range. Smaller 30-100kHz tuning fork crystals often have Q's > around 30,000-50,000 but I don't know the details for the larger tuning > fork cuts. > > I like the "Serial No 2". > > I betcha they knew they wanted a 10Hz bandwidth filter and chose 100kHz for > the center frequency. > > 100kHz is occasionally the last IF of receivers that mostly use LC > filtering at that stage. It is not unprecedented to also allow a crystal > filter there although usually there would be a "phasing control" that lets > the shape/center of the crystal filter be tweakable. > > 10Hz seems too narrow for CW work. But nice round powers of 10 are common > in synthesizers. Wonder if this was a cleanup filter in the innards of a > synthesizer. > > Tim N3QE > > On Sun, Mar 6, 2016 at 2:31 PM, Joseph Gray <jg...@zianet.com> wrote: > >> Assuming I made the pictures small enough, attached are two images of >> an very old crystal filter that a friend found. The strange thing >> about it is the bandwidth - 100 Hz. What could this have been used >> for, with such a narrow bandwidth? >> >> >> Joe Gray >> W5JG >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
