> On Dec 14, 2014, at 9:46 AM, Neil Schroeder <gign...@gmail.com> wrote: > > The oscillator in he m8f is a vctcxo and can be steered with feedback or > controlled by the host. > > Also the m8f can send compliant DAC words to a TLV8515 and and MCP part via > i2c for external > VCXOs. It accepts their return signal on what would normally be its > feedback in ports.
The oscillator in the LEA-6T is not a VCTCXO and it’s got the same notes on it. Bob > > On Sunday, December 14, 2014, Bob Camp <kb...@n1k.org> wrote: > >> Hi >> >> There is also a little note down in the (many) notes section: >> >> Not all features are available with all firmware versions. >> >> It applies to all of the external inputs (like USB and SPI). >> >> Since the oscillator in the uBlox is a TCXO and not a VCTCXO, the aiding >> feature would not help in the case of biasing the unit with a hot air gun. >> It would still loose lock as the TCXO went nuts. >> >> The ideal outcome would be a system that reported against the external >> input rather than the internal TCXO. Since they digitize the external pin >> with the TCXO, the outcome is pretty coarse (10’s of ns). That’s not going >> to help us much. >> >> Bob >> >>> On Dec 14, 2014, at 4:26 AM, Simon Marsh <subscripti...@burble.com >> <javascript:;>> wrote: >>> >>> >>> On 14/12/2014 04:08, d...@irtelemetrics.com <javascript:;> wrote: >>>>> Note that most high-end GNSS timing receivers go one better and >> simply have an external input for the clock. That way you feed your own lab >> clock into the receiver. If you have Rb/Cs/maser you would use that as the >> reference. It's what the national timing labs do, along with dual-frequency >> and post-processing and all the other tricks of the trade. >>> >>>> I think it would be agreat idea also. It's a wonder that more of the >> 'timing' receivers don't have that external clock option! I wonder what >> these Ublox parts use for a clock? Is it something frequency compatible >> with a 10Mhz source??? (Hmm, can we pry one apart to figure it out! ;) ) >>> >>> Ublox modules have a 48mhz internal clock. >>> >>> There is the following interesting paragraph in at least the 7 & 8 data >> sheets: >>> >>> --- >>> >>> 1.8.2 Aiding >>> The EXTINT pin can be used to supply time or frequency aiding data to >> the receiver. >>> >>> For time aiding, hardware time synchronization can be achieved by >> connecting an accurate time pulse to the EXTINT pin. >>> >>> Frequency aiding can be implemented by connecting a periodic rectangular >> signal with a frequency up to 500 kHz and arbitrary duty cycle (low/high >> phase duration must not be shorter than 50 ns) to the EXTINT pin. Provide >> the applied frequency value to the receiver using UBX messages. >>> >>> --- >>> >>> I haven't been able to find any information about what this actually >> does though. Anyone know ? >>> >>> Cheers >>> >>> >>> Simon >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com <javascript:;> >>> 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 <javascript:;> >> 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. _______________________________________________ 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.