Hi there, I don't know how much the Wenzel units are, but if someone is not able to, or willing to build one on their own then this could be a viable alternative. I will look into writing a short appnote describing how a low-noise div-by-2 can be built at home with minimal components using a surface mount '74 chip and a couple of passives. Lastly the 20MHz LTE-Lite boards do generate a 10MHz output of course, and if you feed that into a standard counter (5370B, 53132A etc etc) I think the noise floor of the counter would be higher than the noise floor of the synthesized 10MHz output, so you would not see any difference between using the noisier synthesized output and the low-noise 10MHz TCXO divided output.. Bye, Said In a message dated 10/17/2014 13:19:08 Pacific Daylight Time, [email protected] writes:
How much would we guess that Wenzel blue-top would run you? Relative to the low cost GPSDO, my understanding is the Wenzel parts are priced appropriately to their quality. On Fri, Oct 17, 2014 at 11:32 AM, S. Jackson via time-nuts <[email protected]_ (mailto:[email protected]) > wrote: Hello Jim, let me answer through Time Nuts as this may interest other parties as well. Yes, using a fast flip flop to generate 10MHz out of the 20MHz TCXO 3.0V CMOS output from the LTE-Lite module will preserve the phase noise (actually improve it by up to 6dB due to the 20log(n/m) noise improvement) and will not add any spurs if you use the clean 3.0V output from the LTE-Lite module or an external clean power supply (please note the LTE-Lite TCXO RF output is 3.0V due to the internal 3.3V to 3.0V Low Noise regulator feeding the TCXO and buffer). Use fast logic such as 74AC74, 74FCT74, or the like. We do exactly that on our ULN-2550 boards to generate 50MHz and 25MHz out of the 100MHz, and using a fast CMOS divider will result in additive phase noise that will be below the crystal oscillator phase noise floor. That will result in significantly better phase noise and much lower spurs than using the synthesized 10MHz output from the board, and one 74' chip can generate both 10MHz and 5MHz out of the 20MHz LTE-Lite output. This is exactly what we would do here if we needed a clean 10MHz from the 20MHz LTE-Lite board. I believe you can order low-noise divide-by-2 blue-top boxes from Wenzel already packaged-up and connectorized as well. Hope that helps, Said Hi Said I was one of those looking for 10Mhz but I just thought again now that it might be just as well to divide the standard 20Mhz output by 2 using a FF. I think that would preserve all the desirable characteristics of the 20Mhz signal which I understand to just be square wave at CMOS 3.3v levels anyway. Is that correct? Thanks Jim _______________________________________________ time-nuts mailing list -- [email protected]_ (mailto:[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.
