Charles The goal is to remove the psk so the old phase tracking receivers can work. Whats good about this as I just typed to Bob the signal is slow and easy to work on. >From what I have seen the phase tracking receivers have a fairly long time constant. So the fact that the phase detect and flip occurs 1/10 of a second later should not have any effect on these radios. Regards Paul WB8TSL
On Mon, Sep 22, 2014 at 7:56 PM, Charles Steinmetz <[email protected]> wrote: > Paul wrote: > > One of the methods suggested for working with the wwvb psk is down >> converting to a lower frequency. When experimenting with NAA I had built a >> 24 Khz receiver that down converted that signal to a 100 Hz base band. >> It was a minor effort to shift it to 60 Khz by changing the LO. >> * * * >> for 100 Hz the LO must be at 60.1 or 59.9 Khz. Or synthesize it etc. >> * * * >> Not sure there is a real need to lock the LO at all. >> > > I'm not sure I understand how this helps. > > I thought the point of removing the PSK was to reconstitute a version of > the original unmodulated carrier, so it can be used to discipline an > oscillator at some convenient frequency (the PSK needs to be removed > because it upsets the PLL phase detector). That works (in theory) with a > TRF receiver, because the received carrier IS the tx carrier that is locked > to a standard at the transmitter (modified by the propagation delay and > delay variation, and then by doubling/squaring). But once you convert the > received frequency by using a LO (or BFO, whichever you want to call it), > the recovered carrier frequency is dependent on BOTH the tx frequency AND > the LO/BFO frequency. You have lost the link to the tx frequency standard. > > Am I misunderstanding the goal of the exercise? > > Best regards, > > Charles > > > > > _______________________________________________ > 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.
