It's a whole week since I said something .... not like me
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As forewarned, I have been struggling with Qt (and still am). However at the alpha level of development I have now got the things I want, in particular continuous sampling. Using my "patch the wavetable" technique on the DDS140 I can get up to 8Msps per channel and record these indefinitely without data loss. The only problem is that I cannot get libusb to multiple buffer convincingly, once it has filled the capture buffer, there is data loss. So, when recording traces, I use malloc to dynamically grab the necessary chunk of memory, pass this to libusb and wait for the return. This has three limitations
1) the amount of memory grabbed is finite and variable, but (eg) grabbing "just" 100 megabytes for a 1Msps trace does give you a long sample time
2) you get no trace whilst recording
3) at slower sample speeds, threading and asynchronous use of libusb with small buffers might open the possibility for infinitely long recordings and visualisation ..... but at this stage this would be another learning "event" for me ... and maybe there are others who are more skilled.
As it is I record the grabbed waveforms and store them as raw WAV files, which lots of programmes can read and manipulate. As it happens, this is pretty easy because with the right header you can just append the data to a file straight from the USB read.
Doctormord:
At one stage I was using a triangle waveform to test for data loss (it is really easy to see onscreen). What I also noted was the serious non linearity on the ramp, so perhaps a good way of calibrating against those nasty 4063's.
Failsafe on the AC/DC switches, good question. Even if the firmware initialises correctly, is the hardware design such that the startup state of the FX2 "outputs" correct to select AC mode. And of course if you unplug the scope, the whole thing is floating with respect to the PC.... until you replug it
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bobi_dunkel
Two problems, I cannot find ledioskope ... zero hits on google is pretty rare these days. Could you provide a link if possible please.
I have the dds140, and this is not a simple hardware "upgrade" of the dds120. But I will have a look