Hi > On Mar 6, 2016, at 8:15 PM, Magnus Danielson <mag...@rubidium.dyndns.org> > wrote: > > Hi, > > On 03/07/2016 12:42 AM, Poul-Henning Kamp wrote: >> -------- >> In message >> <caf7opz0srwdmed1av2m_tkyw6k+esr+akka+kn623_lf8kv...@mail.gmail.com> >> , Joseph Gray writes: >> >>> 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? >> >> The 100kHz center frequency pretty much rules out that it comes >> from carrier telephony. >> > > It does not match any of the FDM pilot tone systems that I've seen. > It also does not match the TDM system rates, and this device seems old enough > to almost precursor them.
If it’s a pilot tone, it’s probably part of some sort of tuned instrument rather than a full system. Bob > > Cheers, > Magnus > _______________________________________________ > 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.
