Software-defined GPS receiver: BeagleBone Black + FPGA

Drew On the original  Radio he made the reciever prity much from the base parts and then did the baseband stuff in the FPGA using a soft CPU to do the lifting.

On this guy's design he's used one of the high integration recievers with a seperate SAW filter and a few L's and C's. Did he then copy the other guy's CPU or did he roll or customise his own ??

This part seemed to be missing which in fact may of been the most interesting part given the Radio integration, I was lookin forward to a description of the FPGA contents.

Also what parts did he use for the SAW and the inductors I see that most of those SAWs have 2 or 40ish BW not 20 Mhz which is what the chip's data sheet states or is this a typo ??

I'm all very interested in this cheers

Drew On the original  Radio he made the reciever prity much from the base parts and then did the baseband stuff in the FPGA using a soft CPU to do the lifting.

On this guy's design he's used one of the high integration recievers with a seperate SAW filter and a few L's and C's. Did he then copy the other guy's CPU or did he roll or customise his own ??

This part seemed to be missing which in fact may of been the most interesting part given the Radio integration, I was lookin forward to a description of the FPGA contents.

Also what parts did he use for the SAW and the inductors I see that most of those SAWs have 2 or 40ish BW not 20 Mhz which is what the chip's data sheet states or is this a typo ??

I'm all very interested in this cheers

I think he may have use Andrew Holme's FPGA+code. I've been a long-time reader of A. Holme's web pages - he's done some very impressive stuff, especially with frequency synthesizers. If I was to follow any design, it would be his : )

It's amazing how integrated some ICs are, containing virtually the entire radio, whereas Andrew's one is more discrete and very sophisticated (and he's using a passive mixer). Some approaches are more harder to design into the IC, although I'm not sure at these extremely high frequencies like GPS.

Also it is down to 0402-sized parts at these frequencies (and it looks like it from Andrew's photographs).

Incidentally, I took apart a USB SDR dongle recently, inside it just had two main ICs, and hardly any passive components at all. It didn't pick up many local FM stations, maybe it just needs some filtering (it may be picking up wifi, or other stuff nearby and that may be overloading it).

I think E14 is in need of a FPGA tutorial

Hehe sounds like a challenge...  I will try to convert some notes sometime soon, although maybe there are others with more experience in this area. Regarding devices, I like Xilinx, but I'd love to try Lattice after what John Beetem was mentioning on another thread, and also revisit Altera devices someday (Billabot is experimenting with that for now).

The Xilinx stuff would be fine !!

I think E14 is in need of a FPGA tutorial

http://www.youtube.com/v/gUsHwi4M4xE

Speaking of Forth (which is what Andrew's embedded CPU used), it's not a language I'm familiar with, but anyone seen this device? It's 144 cores. Unfortunately only sold in qty of 10 (a bit too much of a cost just for an experiment) or with a schmartboard (which again is very expensive outside of the US when postal costs are added).

Coder 27 that's not a tutorial but a brief overview  for his tutorial series he's working on but not started yet.

Also I've also made a blog post over it ages ago!!

It's very good but also very much at 10000 ft !!

Yes Shabaz I have it's quite good but yet another entry in to this market in this case you can buy it from the other UK  electronics distributer  that probably won't be mentioned here

Also very much more appropriately I would consider the XMOS parts also they are developed from the original Transputer line that was used in Electronics and wireless world's GPS project in the 90's

shabaz wrote:

 

Speaking of Forth (which is what Andrew's embedded CPU used), it's not a language I'm familiar with...

Forth a wonderful language is.  It very simple syntax semantics and has reverse Polish notation uses you don't need parentheses so objects shown in the order they executed are are and and.  I why it never caught on wonder?

LOL : )