[time-nuts] 10MHz LTE-Lite
Jim Sanford
wb4gcs at wb4gcs.org
Fri Nov 21 23:54:23 UTC 2014
what is the "ublox application"????
Thanks,
Jim
wb4gcs at amsat.org
On 11/20/2014 6:17 PM, S. Jackson via time-nuts wrote:
> Paul,
>
> if you set the serial switch on the LTE-Lite over to the NMEA side then the
> uBlox application will give you all sorts of bar graphs for signal
> strengths, position, time, etc as it decodes all the NMEA messages.
>
> Alex,
>
> the TSC5125A user manual contains a description of the theory in its
> Appendix B. Its probably available on the Microsemi website as I don't think its
> confidential.
>
> Also, I think John's TimePod user manual probably has a description of it.
> Otherwise I remember Sam Stein (who is behind the TSC units) had some PTTI
> or similar presentations discussing the technology, but I don't know where
> those could be downloaded.
>
> Bye,
> Said
>
>
> In a message dated 11/20/2014 14:34:32 Pacific Standard Time,
> alex at pcscons.com writes:
>
>
>
> Hi Said,
> do you have any information about how that "TimePod 5330A works" any
> principal description?
> 73
> KJ6UHN
> Alex
>
> On 11/20/2014 2:08 PM, S. Jackson via time-nuts wrote:
>> Hello Mike,
>>
>> attached is a 10MHz DIP-14 TCXO Phase Noise plot from a random LTE-Lite
>> unit.
>>
>> I had sent out a 20MHz typical phase noise plot some weeks ago, and
>> comparing the two they are almost perfectly 6dB apart as would be
> expected from
>> the 20log(n/m) relationship. There are variations from unit to unit of
>> course, but it does not seem like one version of the board or the other
> has
>> advantages in terms of phase noise.
>>
>> I had also sent out a superimposed plot of the 20MHz and the divide-by-2
>> 10MHz output of the same board at that time, and again the relationship
> was
>> almost perfectly 6dB lower at 10MHz versus 20MHz.
>>
>> While phase noise follows theory, it does seem that the DIP14 metal
> shield
>> has a beneficial effect on the ADEV stability though. The plots we are
>> getting are pretty darn good, and I want to test more boards before I
> post any
>> ADEV, because its quite a bit better than our specification and I want
> to
>> make sure its real.
>>
>> The 10MHz DIP-14 boards do not have an isolating buffer like the 20MHz
>> boards do, on these the TCXO drives the output directly, so one must be
> careful
>> to set the equipment to 1M Ohms input impedance or use a buffer
>> externally, which is what we did to measure the attached PN plot.
>>
>> Bye,
>> Said
>>
>>
>
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