General > General Technical Chat
Review: Hantek DDS 3X25. Anyone own one?
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marmad:

--- Quote ---in order to confirm this, i need to do thousands of test, and automated.
--- End quote ---

Hmm, this seems a little strange. When I downloaded your software to create a stable sync signal out, I didn't do thousands of tests - I just tried a few known unstable frequncies to see if it worked.  All I was looking for here, as mentioned in the original post, was someone to test a few frequencies to see if it worked, so that I could move ahead in my development.  Anyway, it's fine... another 3X25 user PM'ed me earlier today that it works perfectly on their device, so he confirmed it was the correct clock formula and reverse logic for 3X25.


--- Quote ---as i PMed you, your sweep software cannot run, there's ActiveX object you didnt provide. i also looking forward for glitch free sweep, even though implemented at lower range of frequency, but as you said, very well enough/applicable in audio region.
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Yes, as noted below, if I had gotten feedback anytime in the last 3 days, I would have removed the unintended ActiveX reference. But, again, I've confirmed the glitch-free sweep myself with my new scope - see attached .png.


--- Quote ---i understand your frustration of cold reply. with many hours of sitting infront your pc coding and then people would not appreciate what you are doing is like you are doing it for a waste, but its not. other people are just busy or not in the mood to look at this subject.
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Actually, it's fine if people are not looking at the subject - I was just asking for help from owners who read the post and downloaded the software.


--- Quote ---if you need to take a break this is the time, withdraw your method here
--- End quote ---

I'm not sure what this means.


--- Quote ---I do appreciate your work. But, Your Sweep_test crashs (snapshot attached).
--- End quote ---

Thanks. This is 'feedback'; exactly what I was looking for.


--- Quote ---The point is, you should never do such hacking to impress others or to compete with others. As you have just learned, it only ends up in frustration.
--- End quote ---

I'm not sure what this has to do with what I was talking about - I have, in no way, done any of this to impress or compete - I hack because I need to create tools to get hardware/software to perform functions I need for what I'm doing in my life - and I enjoy it.  I post here because I want to share information and get feedback and help with stuff I'm working on.  The two are not related - I was hacking for years before the web; i.e. before blogs and forums - although we did have community boards on the net - but it took a hell of a lot longer, if it all, to get feedback  :)


--- Quote ---By the way, I am surprised that no one until now seems to have used a USB protocol sniffer to figure out what these magic DLL functions really send to the generator. For example to figure out if they do some own special math or if the generator gets the values more or less as provided to the functions.
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I'm decompiling the DLL.


--- Quote ---Please don't be discouraged. I was one of the ones who downloaded it. Just trying to get some time to try it out for you -- I was away from home yesterday and I am babysitting the grandkids right now. But I am eager to beta test as soon as I can.
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Thanks, Torch.  You don't need to test those modules above anymore - they have been confirmed.  But I will have more stuff later ;)

Edit:  Moved formulas and software back to the original post where they belong,
saturation:
Just a headsup, you guys are doing a great job.  Consider where this device was when we started.  Will feedback later.
marmad:

--- Quote --- 4). Implications to  frenquency sweeping:
  4.1). If one can accept <20% frenquency step as good enough, one can use F_clock (<)2k to 20MHz for sweeping with the same waveform. This means a sweeping range of 4 decades.
  4.2). A single waveform can have 1 to (>)1000 periods. That is for a single waveform one can either sweep from 1Hz to 10kHz, or from 1kHz to 10MHz or any 4 decades range in between. For example, to sweep (1k to 10MHz).
--- End quote ---

As I mentioned in my post of this morning (but did not have time then to respond in-depth), this is not possible with glitch-free sweeping (although you can do any kind of sweep you want if you don't mind pauses and/or glitches).  Since the DDSSetFrequency command sets a divider on the 200MHz clock, any frequency <= 48828.12 sets the DAC clock to between 2.048kHz and 100MHz - and any frequency >= 48828.13Hz sets it directly to 200MHz - after which you need to change number of points to change frequency.  So any sweep crossing that boundary will immediately double in frequency.  In fact, because of the design of the divider, DAC clock rates change exponentially as the frequency rises - for example, my audio log sweep produces the following numbers because it misses a couple of frequencies towards the end because of this property:
10 20 30 40 50 60 70 80 90 100 200 300 400 500 606 701 800 909 1000 2000 3076 4000 5000 6666 8000 10000 20002 40008


--- Quote ---Just a headsup, you guys are doing a great job.  Consider where this device was when we started.  Will feedback later.
--- End quote ---

Thanks for the words of encouragement...  They're appreciated!
Mechatrommer:

--- Quote from: marmad on August 05, 2011, 03:56:45 pm ---
--- Quote ---in order to confirm this, i need to do thousands of test, and automated.
--- End quote ---
someone to test a few frequencies to see if it worked,
--- End quote ---
for few frequencies it work! but i still dont fully understand how your program works.

--- Quote ---so he confirmed it was the correct clock formula and reverse logic for 3X25.
--- End quote ---
you havent share it yet. thats only between you two.shared! :P

--- Quote ---
--- Quote ---if you need to take a break this is the time, withdraw your method here
--- End quote ---
I'm not sure what this means.
--- End quote ---
it means share your code pls. as i'm also working on this right now.

edit: i saw your formula already thanx. i will investigate it in alot more extensive way than mouse click method ;)
Mechatrommer:
while testing your sweeptest3. i saw this picture. it happened for square wave while sweeping at 10-50 Hz. pls check whether this is your app mistake generating square wave or artifact from the hardware (yellow=signal, blue=synch out). you have extended the possibility of stable sweep at lower frequency, great work!
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