| General > General Technical Chat |
| Review: Hantek DDS 3X25. Anyone own one? |
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| Mechatrommer:
nop. i'll refer back to this formula when i'm working back on it. |
| marmad:
I found another weird little bug in the Hantek while writing my software for it: there seems to be a range of frequencies that cause the clock to lose a divider bit - but I'm not sure how this happens (some firmware bug or incorrect design inside the FPLA) or if it's just confined to my unit. Could someone (Mecha??? :D ) see if this exists on their unit as well? I'd appreciate it. It's easy to test: just hook the output into the count input = start the Hantek software - set the frequency for exactly 50,000Hz. This should be a perfect frequency for the Hantek running a 200MHz clock. It's suppose to use a 4000 pt sample length to get the correct frequency (200MHz /400 = 50MHz) but instead it drops a bit and uses 3999 and ends up precisely on the frequency 50012.5Hz On my unit it appears to do this with all frequencies in the approximate range of 30kHz to 60kHz. This is definitely something happening inside the device, since it does the same thing with my software or with the Hantek software. On another note, the first version of my control software is almost done - just ironing out bugs in the logarithmic sweep routing - it incorporates Mecha's stable sync feature - with a function generator interface. Hopefully I'll get it posted in the next day or two. |
| Mechatrommer:
some mistake in your calculation, please clarify. i assume its 50kHz you are asking. so i tried that no problem, as my little tool reported (data length) below, its using 4000 points (returned from DDSSetFrequency), not 3999. and my "poor" rigol's frequency counter says 49.992kHz. set hantek to 30kHz, read by rigol as 30.0026kHz (3333pts), 40k = 39.9995k (2500pts), 60k = 60.0053k (3333pts). anyway does your software looks like in the 2nd picture? ;) i'll be looking forward to it. |
| marmad:
--- Quote ---some mistake in your calculation --- End quote --- Thanks for the test! Hmmm... it must be a blip in the frequency counter on my Hantek (I don't have a new scope yet to try test on) - it was just so repeatable, I assumed it was a settings bug. Here's the first version of the new software... I borrowed code from you and from another person's AWG interface - I will put credits in the About box in the final version. I don't have time at the moment to write help for some of the features - but the only things which are still unfinished: About/Help (of course), a waveform display, and the arbitrary wave editor library functions, but all other settings and features of the DDS-3X25 are implemented. Main thing to note: when you set a frequency, you get returned the actual closest frequency the Hantek can respond with - or, with Stable Sync (shafri's code) selected, the closest frequency the device can do with a stable Sync output. I will post more info about the features and pictures of a test rig later tonight or tomorrow. Enjoy. Edit: Fixed "comm failure" bug; changed sweep output to no pause between waveforms; enabled frequency tuning in Display Controls (double-click Current Settings): allows tuning of frequency or voltage data sent to the Hantek (or frequency1 display in the software) to correspond with real world data. DDS3X25Ctl_0_9.zip (74.78 kB - downloaded 8 times.) Edit2: Removed this version - and posted newer version (with bug fixes and some added help) in post on Page 19 of this thread. DDS3X25Ctl_0_9_1.zip (75.17 kB - downloaded 14 times.) |
| Mechatrommer:
ok tried that, cool, esp the 7 segments display on bottom left. tried the 50kHz freq, no problem my rigol still read 49.9993kHz. |
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