Hi Wolf, Stefan, Jim, LF
If your choice is a Ublox NEO-M8N, the PPS time pulse is configurable (sw
Ucenter via RS232 interface) from 0.25Hz to 10MHz with a duty cycle from 0%
to 100%. The module is based on a good internal TCXO with a RMS accuracy of
30ns.
Now, my operational homemade GPSDO it's composed by an OCXO (16384 kHz) locked
in phase with a NEO-7M (crystal oscillator, configurable time pulse) through
some divisors.
I'd try to use only a NEO-M8N (without any other external OCXO) to generate a
valid reference timepulse for EbNaut/Opera modes. But will it work?
Datasheet link:
https://www.u-blox.com/en/product/neo-m8-series
All the best,
Riccardo, IW4DXW Giovedì, 27 Ottobre 2016, 11:04AM +02:00 da DK7FC <
selberdenken@posteo.de> :
>Hi Wolf,
>
>According to https://www.u-blox.com/de/history , u-blox, the company
>which builds the module, is coming from Switzerland. So it's not really
>a chinese product. :-) Just the board is most probably built (soldered)
>in China.
>
>73, Stefan
>
>Am 26.10.2016 23:46, schrieb Wolfgang Büscher:
>> Hello Jim,
>>
>> I wouldn't give up on the Thunderbolt E yet. A double-ovenned 10 MHz
>> sounds intriguing, you should have a very low phase noise which other
>> GPSes (clocked by a cheap 'computer grade' oscillator) cannot achieve.
>> It will be interesting if you use the Thunderbolt to trigger a
>> digital oscilloscope, and measure the PPS signal from the chinese
>> unit at a resolution of a 10 ns or so.
>>
>> With a simple pulse-shaping network (CMOS 4093 wired as a crude 10 us
>> monoflop), the pulse digitized with an E-MU0202 look good enough to be
>> used as a timebase with SL. I will play with a modified algorithm, and
>> see how it compares with the edge-interpolation on the 100 ms pulse
>> from the Garmin - also at lower sampling rates (with sampling
>> intervals longer than 10 us).
>>
>> Cheers,
>> Wolf .
>>
>>
>>
>
|
