Hi
On Jun 2, 2013, at 4:05 PM, Jim Lux <jim...@earthlink.net> wrote: > On 6/2/13 12:52 PM, WB6BNQ wrote: >> Hello Mark and crowd, >> >> I own one of these and I can guarantee that it CANNOT be moved without >> changing the crystal, tweaking a >> micro-minature coil value, and changing the firmware. And NO !, the company >> would NOT send out the firmware >> needed. However, if you wanted to spend between $500 and $1000 they would >> fix it for you. >> >> While there is a DDS inside, it and the crystal are part of Rubidium >> frequency locking loop. The actual output >> frequency is generated by dividers in a big ASIC/FPGA/whatever device. YES, >> that output frequency is derived from >> the crystal frequency. >> >> They start by choosing a output frequency which selects the crystal >> frequency. The crystal is multiplied up to some >> frequency and mixed with the output of a DDS (also driven by the crystal) to >> produce the final frequency multiplied >> further to get to the Rubidium resonance. So, without a change in the >> firmware, there is no way to tweak the unit >> more than a very small amount. >> >> BUT all is not lost. The 9.8304 MHz frequency is related to the common >> RS-232 modem frequencies. It is also >> related to the common sound card frequency of 24.576 MHz. There it is >> possible to phase lock it to 10 MHz. >> > > You mean bit clock, not modem, I think.. 9.8304 M = 512 * 19.2 k so you can > make all those baud rates down to 300 baud/sec. I don't think you can get 110 > bps, but you could even Rb lock your old ASR33 by dividing down to 60 Hz (it > evenly divides to that) and running the synchronous motor off that. The 3X burp when they go to 19.2 x 3 = 57,600 (and then to 115,200) would also give you some problems ….. Bob > > That 24.576M sound card is at 2.5x > _______________________________________________ > 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.
