Another Clone that Might not Suck 

Buoyed by the ADS1293 success, I started trolling (in the classic sense) my favorite mass retailer of dubious breakout boards for DDS's a bit more capable than AD9833's or AD9834's.  In particular, I wanted dual DDS's for quadrature capability, AM capability, and (hopefully) FM/PM capability.   The AD9854 seemed to fill the bill, but most example boards were a bit on the salty side, price-wise.  I did find one for $65 (US) which was way better (price-wise) than the rest. 
 
Anyway, I bought one of these.  It came with a stick-on heat sink and a power pigtail that plugs into its own connector.  No software, no instructions.  "Control boards" could be sourced from the same mass retailer, but there wasn't much indication the software's source code was available or that the control boards with work with this AD9854 board.  It was time to dive in and see if I could get it running or if I shafted myself.
 
About six or seven years ago, I endured the tedium and frustration of writing a library and test sketches for the AD4351 synth.  I had an old AD4350 library to start from, but I spent an inordinately large amount of time digging through the register maps and register read/write routines trying to get everything working.  Eventually, I got it work correctly, but it was not a good experience.  I wasn't going to do that again - these are the types of things that AI is really good at (if you carefully ride herd on it).  It took Claude about 5 minutes and three iterations to come up with a Pico 2 test sketch that worked.  (Pico 2s are cheaper than Teensys and I happened to have one available.)  You can find the test sketch at https://github.com/dave-metzler/AD9854-PICO2-test.  Use it at your own risk.  It uses the parallel control mode for the AD9854.  Here it is in its hay-wired (but not connected to power) glory:
 
and here's the output on the TinySA:

 
I used an AD8302 phase/gain meter for a quick check of amplitude and phase balance between the channels.  They were within + 1db and with 1 deg of 90 deg phase offset through 50 Mhz.  That's close as that meter gets.  I'll check it with the scope, soon.  The actual max output level was -10dbm (I had a 10 db attenuator in line to protect the TinySA).  I still have to look at output level and phase offset variation with frequency.
 
Serial control mode also works, but is somewhat finicky.  Since Pico2s and wires are relatively cheap, there's really no reason to use serial control.
 
One item that needs addressed is thermal management of the AD9854.  I used the stick-on heat sink that came with it and I could run the board for at least ten minutes and still hold my finger on it, somewhat uncomfortably.  I normally don't like to let things run this hot, so a small fan or larger heat sink might be in order for extended run times.
 
Ultimate image reject DCR or polar modulation maybe??? 
 




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