> John, > > On 08/01/11 16:08, J. Forster wrote: >> Pondering some more on this, doing some calculations (spread-sheets) the >> actual scheme emerge... the range of 0 to 7 is not selected by accident. > > I had essentially the same spread sheet... > > However, how would you be able to achieve simplicity of design by being > true to the PRI/PRR given or to what seems like reasonable counter based > solution.
I think the PRR of the transmitters was crystal controlled. I'm gettring a Test Set with a 1.81818 KHz crystal in it... yes 1818.18 Hz!!... that simulates a transmitter. The receive set seems to be free-running, crystal referenced. I don't think it automatically locks up on the Master pulse. I see no indication that the received signal connects to any timing stuff. > Notice that the ARN-4 has a "Crystal phasing" control to > adjust the crystal frequency of the receiver so that the receiver will > align up to the actual rate of the master station. The DAS-1 has a left-off-right control on the master crystal. It seems like thye operator manually saligns the Master pulse, and the drift rate is low enough to allow TD measurement. > I think the PRI/PRR given is a presentation simplification rather than > true numbers. Certainly possible, althyough 100 uS increments is pretty simple too. > Considering that absolute frequency was not a requirement, > the repetition rate of the master needs to be sufficiently stable for > distinction of station and the receiver to make stable reading, in > presence of other stations. > > That LORAN-C uses GRI indications with repetition rate in microseconds, > and fairly even such numbers as well, is another hint. > > Thus, I view the PRI/PRR ratios as approximations at best, a matter of > presentation rather than actual nominal rates. > > Cheers, > Magnus I don't know. It's certainly an interesting possibility. Thanks, -John ================= > > _______________________________________________ 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.
