DSO203 GCC APP - Community Edition (2.51+SmTech1.8+Fixes)

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pmos69
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Re: DSO Quad GCC port (2.51+SmTech1.8+Fixes)

Post by pmos69 » Tue Mar 06, 2012 8:56 am

Code: Select all

v1.14
- More (clueless) FFT tweakings
		Replaced the Hanning Window
		Applied dumb automatic scaling to the bars (based on max frequency)
		Removed "bluring"
Download: https://github.com/pmos69/dso203_gcc/zipball/master
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horse
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Re: DSO Quad GCC port (2.51+SmTech1.8+Fixes)

Post by horse » Wed Mar 07, 2012 3:56 am

paf wrote:Yes, Marco and then Pedro did a great job, thank you very much. And the work of Pedro allows each of us to compile the firmware using a free compiler.

The integration of FFT is very nice but I don't understand what it measures exactly. Look at the following example (230V mains with 10x probe):

Two things irritate me:
  • why so many harmonics? The mains should be a very good sine, I don't expect anything significant above 50Hz. Is this noise because of the limited resolution of the ADC? Or a "feature" of the FFT? Of because of the vertical logarithmic scale?
  • the rays in the spectrum are not really rays, they are rather blurred - is that a "feature" of the FFT too (e.g. because of the width of the bandpass filter?)
Patrick
220 ac from wall it very very dirt source ))
because of many consumers like flyback power source, gas discharge lamp, etc

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Re: DSO Quad GCC port (2.51+SmTech1.8+Fixes)

Post by paf » Wed Mar 07, 2012 6:55 am

horse wrote: 220 ac from wall it very very dirt source ))
because of many consumers like flyback power source, gas discharge lamp, etc
...right but compared to the awful "sine" of the quad, it is almost perfect :D
Patrick

pmos69
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Re: DSO Quad GCC port (2.51+SmTech1.8+Fixes)

Post by pmos69 » Wed Mar 07, 2012 7:56 am

paf wrote:
horse wrote: 220 ac from wall it very very dirt source ))
because of many consumers like flyback power source, gas discharge lamp, etc
...right but compared to the awful "sine" of the quad, it is almost perfect :D
Patrick
Yes, but sampling it with 8 bits will get it just as awful :)
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pmos69
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Re: DSO Quad GCC port (2.51+SmTech1.8+Fixes)

Post by pmos69 » Wed Mar 07, 2012 1:38 pm

Code: Select all

v1.15

- Small optimizations in some FFT operations
- Fixed FFT max frequency and scale max frequency display for time scales less than 10uS/Div
https://github.com/pmos69/dso203_gcc/zipball/master
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Re: DSO Quad GCC port (2.51+SmTech1.8+Fixes)

Post by Jerson » Wed Mar 07, 2012 2:21 pm

Hi Pedro

Wonder if you can look at this. I tried looking at the code, but can't figure out where it is going wrong.

See this video that shows the GCC version in SCAN mode. Here you will see the waveform is printed in 3 distinct segments that repeat themselves.
http://youtu.be/2zUi5dcPvrQ

This is another video with the AP1_100 version in SCAN mode with buffer set to 360(smallest setting). This problem does not happen here. Sad we don't have the sources for AP1_100
http://youtu.be/VU-VZ2kq62M

Please let me know if I there is a way I can help. Right now, I cannot figure out the whole code, so, not sure where to look. But, I am guessing SYNCHRO and PROCESS are the right places to look.

Regards
Jerson

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Re: DSO Quad GCC port (2.51+SmTech1.8+Fixes)

Post by chip » Wed Mar 07, 2012 4:13 pm

horse wrote: 220 ac from wall it very very dirt source ))
because of many consumers like flyback power source, gas discharge lamp, etc

sine wave of 220 with transformer

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Re: DSO Quad GCC port (2.51+SmTech1.8+Fixes)

Post by pmos69 » Wed Mar 07, 2012 4:33 pm

Hi chip,

...that means you can/will contribute to the project?

All the best,
Pedro
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chip
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Re: DSO Quad GCC port (2.51+SmTech1.8+Fixes)

Post by chip » Wed Mar 07, 2012 5:03 pm

pmos69 wrote:Hi chip,

...that means you can/will contribute to the project?

All the best,
Pedro
I'm sorry, but I have my own project.
Picture order was to compare. In 220 no loud noise.

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Re: DSO Quad GCC port (2.51+SmTech1.8+Fixes)

Post by pmos69 » Wed Mar 07, 2012 5:30 pm

chip wrote:
pmos69 wrote:Hi chip,

...that means you can/will contribute to the project?

All the best,
Pedro
I'm sorry, but I have my own project.
Picture order was to compare. In 220 no loud noise.
No problem.
Do you have your source code available to the public?
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