On Wed, Jun 6, 2012 at 9:33 AM, Eric Garner <garnere@gmail.com> wrote: > On Tue, Jun 5, 2012 at 12:53 PM, Attila Kinali <attila@kinali.ch> wrote: >> On Tue, 05 Jun 2012 15:40:48 -0400 >> Michael Tharp <gxti@partiallystapled.com> wrote: >> >>> On 06/05/2012 03:31 PM, Attila Kinali wrote: >>> > * The XC6SLX9 is<10USD more expensive than the SLX6. I think the added >>> >    value of having twice as much "real estate" would justify the additional >>> >    price. >>> >>> Some vendors don't even stock the SLX6, including Digi-Key! Agreed >>> though, it would be neat if a CPU capable of doing fixes could be fit >>> onto the FPGA alongside. Might be impractical though, a DSP would >>> probably be more appropriate. Still, from what I can tell a FPGA makes a >>> decent PPS-level phase comparator. You can even gang them up with a >>> phase-shifted clock to get finer resolution. >> >> Yes, there are at least half a dozen ways i can think of to use this >> board in combination with other boards or various uC and DSPs. And >> everyone has their own pet uC/DSP/board that he'd like to use. >> Thus i think some easily accessible header pins would be better than >> putting a uC directly on the board. >> >>> > How about design tools for the FPGA? As far as i can tell, the ISE WebPack >>> > does not support the Spartan 6 family. >>> >>> WebPack does support XC6, or at least the mid-range parts and below. I >>> have a XC6SLX45 dev board and have no problems generating bitstreams. >> >> Cool. It thought it was strange that the WebPack FAQ listed only spartan3. >> But i couldnt find any other reference listing the supported FPGAs. >> >>                        Attila Kinali >> >> >> -- >> Why does it take years to find the answers to >> the questions one should have asked long ago? >> >> _______________________________________________ >> 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. > > I just accessed the book on SpringerLink and it looks fantastic. > Fortunately my company's library lets me have full access to the text > of the book. However, it does not appear that they let me download the > matlab code that comes on the CD that comes with the book. do you know > if it's available somewhere? > > > > -- > --Eric > _________________________________________ > Eric Garner > > _______________________________________________ > 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.

Oops, sorry, hit the send button too soon. Another nice book on GPS signal processing is the one by James Tsui, _Fundamentals of Global Positioning Receivers: A Software Approach_. I learned a lot from it. Cheers, Peter

Hi Attila, > Could you also add just the option of a power splitter at the input? I'm not really sure what the most appropriate RF interface is. I was planning to make another much simpler board with just a bias tee, a 3:1 splitter, and some hairpin microstrip filters. Then it would be three short SMA cables over to the main board. (Right now I just have a 2:1 splitter and I'm relying on the L1/L2 antenna for filtering.) Maybe it would make sense to integrate the splitter, filters, and bias tee at some point, since an auxiliary board is always more hassle, and the connectors and cables are expensive. One thing I didn't want to do is commit to any particular filter technology up front. Ceramic filters, and, worse, SAWs, have delays that vary with temperature (to say nothing of the large NRE costs involved). Microstrip filters would have a lower temperature coefficient I think, though they are not as sharp and have more loss. Cheers, Peter

> [ Borre GPS book ] > > However, it does not appear that they let me download the > matlab code that comes on the CD that comes with the book. do you know > if it's available somewhere? I think it's here: http://kom.aau.dk/~borre/easy2/ The last entry, the zip file, looks to be the most recent. From the size, it probably includes some example sky recordings. Cheers, Peter

		Attila Kinali

On Wed, 6 Jun 2012 10:08:24 -0700 Peter Monta <pmonta@gmail.com> wrote: > I was thinking to do a resistor-programmable option to either use the > 10 MHz or the TCXO as input to the LMK03806. I'm not sure there's a > huge advantage to using a more stable clock, though. The TCXO is > probably plenty good enough for keeping the carrier PLLs in > lock---it's a fairly high-end TCXO which is not cheap ($18). Using > the 10 MHz (or 100 MHz) does have the merit of potentially saving the > cost of the TCXO, but many users would probably want a board that just > works, without a lot of external doodads to hook up. There is. The paper "Ultra Stable Oscillators - Limits of GNSS cohrerent integration" by Gagero and Borio[1] gives a nice overview what you can acheive if you have a more stable oscillator. Gaggeros master thesis[2] goes a bit further into the details of how the experiment was setup and what results came out. Attila Kinali [1] http://plan.geomatics.ucalgary.ca/papers/ion08_ultrastable_pascalg_26sep08.pdf [2] http://plan.geomatics.ucalgary.ca/papers/msc_thesis_gaggero_feb08.pdf -- Why does it take years to find the answers to the questions one should have asked long ago?

		Attila Kinali

On Wed, 6 Jun 2012 10:24:12 -0700 Peter Monta <pmonta@gmail.com> wrote: > Hi Attila, > > > Could you also add just the option of a power splitter at the input? > > I'm not really sure what the most appropriate RF interface is. I was > planning to make another much simpler board with just a bias tee, a > 3:1 splitter, and some hairpin microstrip filters. Then it would be > three short SMA cables over to the main board. (Right now I just have > a 2:1 splitter and I'm relying on the L1/L2 antenna for filtering.) I would at least give the option to use one antenna for multiple inputs. > One thing I didn't want to do is commit to any particular filter > technology up front. Ceramic filters, and, worse, SAWs, have delays > that vary with temperature (to say nothing of the large NRE costs > involved). Microstrip filters would have a lower temperature > coefficient I think, though they are not as sharp and have more loss. Yes, i dont have a good solution either. Maybe someone of the guys here with more knowledge on RF design could have a look at that? Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago?

> http://kom.aau.dk/~borre/easy2/ Oops, sorry, that was for the previous book. For the software-receiver book, you want this page: http://kom.aau.dk/project/softgps/ I'm not sure the source code is in the demo CD image, though (the "GPS SDR demo" link). Cheers, Peter