Hi Pete, I had a similar experience, got several AD9851 DDS boards here in various signal generator and VFO projects.
They do work well, but when I first used them, I was surprised to see just how many spurs appear as you tune across a range of frequencies, and some are pretty big as well! That's why it was really nice to try the Si570, and see how good the output was, just a pity it costs that bit more. I wish you success with your project and venture. Nice to see an ever increasing range of SDR hardware becoming available. I suspect there is a good market for a ready constructed module as many find it too hard to cope with building using SMD components. 73, Bob G8VOI --- In [email protected], "ni9n" <peg...@...> wrote: > > > Thanks, Bob! I was a little surprised when I started experimenting with the > AD9834 to find all the spurs it produced, especially above one-quarter of the > master clock frequency. When I figured out why the DDS generates spurs, I > quickly came up with a way to nearly eliminate them. It's really the only > thing about the LD-1 that's proprietary. > > --- In [email protected], "g8voip" <g8voi.reeves59@> wrote: > > > > Hi Kelvin, > > > > Just a trivial point. > > > > The Si570 is not actually a DDS device, uses a completely different method > > of generating the final frequency. The net result is that the Si570 has a > > much clearer output spectrum, and none of the spurs usually associated with > > DDS chips, also the Si570 has lower phase noise. > > > > Although it does cost a little more, certainly worth it. > > > > It has has become the 'standard' oscillator source now for a number of > > different SDR projects. > > > > 73, Bob G8VOI > > > > > > --- In [email protected], "kcmuthumani" <kelvinm@> wrote: > > > > > > Hi Pete. > > > > > > This SDR looks very nice, before I order one do you have some specs on > > > the unit ? I was wondering if you are going to post the schematics > > > online. I could not find it on your web site. Also what DDS chip are you > > > using Si570 ? or Analog Devices chip ? > > > 73 > > > Kelvin > > > > > >
