EMRFD Message Archive 10493

Message Date From Subject
10493 2014-11-25 08:42:01 raccoonnyc Si5351 VFO/BFO

I just put up a video yesterday of my Adafruit si5351 breakout board. I used the very excellent NT7S si5351 Arduino library and code stolen from a variety of other hams to write the software. References are at the site. The VFO/BFO is installed in my test receiver made of modules from W7ZOI, KK7B and WB6DHW. It’s a rather hastily produced video done mainly because the bands sounded so good yesterday morning.

The little Adafruit board has three outputs, of which I’m only using two. Eventually I would like to use the third for generating a cw signal for a power amplifier. Phase noise measurements of the Si5351 can be seen at NT7s.com.

Tom, ak2b

NT7S Adafruit si5351 VFO/BFO


10494 2014-11-25 09:01:46 Roelof Bakker Re: Si5351 VFO/BFO
Op Tue, 25 Nov 2014 17:41:01 +0100 schreef tom@portronix.com [emrfd] :

 

I just put up a video yesterday of my Adafruit si5351 breakout board. I used the very excellent NT7S si5351 Arduino library and code stolen from a variety of other hams to write the software. References are at the site. The VFO/BFO is installed in my test receiver made of modules from W7ZOI, KK7B and WB6DHW. It’s a rather hastily produced video done mainly because the bands sounded so good yesterday morning.

The little Adafruit board has three outputs, of which I’m only using two. Eventually I would like to use the third for generating a cw signal for a power amplifier. Phase noise measurements of the Si5351 can be seen at NT7s.com.

Tom, ak2b

NT7S Adafruit si5351 VFO/BFO





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10496 2014-12-01 04:37:40 jorschei Re: Si5351 VFO/BFO


Hi Tom  ak2b,

Interesting video about the Si53551A  clock generator. It is a useful chip to built an VFO like the Si570 from Silicon Labs.  We intend to use it for a SDR receiver and the audio tests sounds good. Also a low current consumption important for mobile use.

Tanks for the video input,  Joris PE1KTH.


10497 2014-12-01 04:43:25 Dennis Anderson Re: Si5351 VFO/BFO
Hi All

Look at Paul m0xpd Blog  m0xpd's 'Shack Nasties'regards to the Si5351A, also his ideas on SDR

also Kanga Products (UK) has the Si 5351 breakout board in stock for UK & Euro shipping

Regards

Dennis G6YBC

10544 2014-12-06 02:56:30 jorschei Re: Si5351 VFO/BFO

Hi Dennis,

Yes I know the site of  moxpd  and other Si5351A publications.

I have develop a 24 pin DIL  VFO  plug in module PCB with the Si5351A  witch has to be tested yet.

Still want to investigate the possibility to generate an I and Q  clock signal for direct conversion SDR receiver prototyping with an SN74CBTLV3253 mixer. Another problem. Hi....

73' Joris PE1KTH

10545 2014-12-06 05:43:18 Dennis Anderson Re: Si5351 VFO/BFO
Hi Joris,

Basically it is watch this space, as there are a lot of guy's out there playing with what is turning out to be a great little devise.

The AD9850/51 still has a place and there are few idea's and projects out there that are and have been used for the same idea's to generate I & Q signals.

Good luck, myself and the group look forward to hearing your exploits.

Best regards

Dennis G6YBC

10546 2014-12-06 12:23:12 Chris Howard w0ep Re: Si5351 VFO/BFO
I am messing around with my NT7S board today
and I have not yet found any way to get either
the phase shift or the invert mode to work.

I don't think the phase delay feature will
work to make an I/Q VFO. But the invert mode
might be nice.

If someone can figure out how to make it work.

Chris
w0ep


10547 2014-12-06 13:25:16 Thomas S. Knutsen Re: Si5351 VFO/BFO
Assuming you are using  the Arduino code from Jason NT7S?
If you look at the bottom github page for the library: https://github.com/etherkit/Si5351Arduino
Under the To Do list:
Implement phase register access
Since phase register access is not implemented into the library yet, it would not work.
That said, the .CPP file have all you need to do get it to work, you just need to add a couple of lines of code for it to work.

Since this is open source code, you can fork the library, add the access and then send NT7S a pull request to get the function implemented into the library, or you can wait untill NT7S gets around to it, I know he have somthing taking up most of his time at the moment, so it may be a while.

The library and the SI5351 works quite well, with decent phase noise (check http://nt7s.com/ ) and cheaper than other oscilator alternatives. Based on my little experience with the chip, I would reccomend using a divide by 2 or 4 to get the quadrature, the accuracy I got when testing it was not that great.I know Jas
10548 2014-12-06 16:23:45 Chris Howard w0ep Re: Si5351 VFO/BFO
I'm glad you got it working, that gives me hope!

I am using Jason's library
and it looked like there was a recent addition of
a set_phase function, but maybe it is not all there yet.

Chris


10549 2014-12-07 08:56:53 Jason Milldrum Re: Si5351 VFO/BFO
I apologize to Chris and others for the confusion. I made some tweaks to the documentation, but I neglected to switch from my development branch to my master branch, and ended up accidentally publishing the unfinished code. I'm still learning all of the ins and outs of working with Git and GitHub, sorry!

Actually Chris, you should be able to get phase shift to work, you just have to issue a PLL reset after commanding the phase shift. Try this raw command for now until I get the phase shift properly implemented:

si5351.si5351_write(177, 0xAC);

Because the phase shift register is only 7-bits and is limited to time increments based on the PLL frequency, it's not really that great and probably won't work in some cases. The better bet, if you need an I/Q LO for HF, is to just use the old /4 FF circuit like the one used with the Si570 in the Softrock rigs.

FWIW, I'm giving strong consideration to using a crowdfunding platform to raise funds for a run of the Si5351A Breakout Boards, and I think for one of the stretch goals, I'll sidetrack some of my time from other projects to polish up the Si5351A Arduino library, if I can get some extra funding to help. Glad that my library has been helpful for a few folks!

Jason NT7S