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Old 8th February 2008, 01:09 PM   #21
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out after notch
0.5v/div, 2us
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Old 8th February 2008, 01:10 PM   #22
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out before notch
1v/div, 1us
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Old 8th February 2008, 01:12 PM   #23
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out before lc filter
20v/div, 1us, positive
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Old 8th February 2008, 01:13 PM   #24
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out before lc filter
20v/div, 1us, negative
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Old 8th February 2008, 01:14 PM   #25
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Same white noise....
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Old 11th February 2008, 05:28 AM   #26
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Even if i replace floating smps with 2 x 9v bat, still noisy.
Even if i remove inductor from pcb (at about 20cm), noise is still the same...
Even if i put a more decoupling caps for vcc (ceramic, mkt, etc) ...
Even if i put rc snubbers; scottky antiparalel diodes, adjusting deadtime, etc... still the SAME noise...
6N137? ... i don't know...
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Old 11th February 2008, 06:28 AM   #27
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Try adding more capacitance to the outputs of the L7805...
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Old 11th February 2008, 06:40 AM   #28
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... tryied...
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Old 11th February 2008, 08:23 AM   #29
Eva is offline Eva  Spain
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Try increasing and decreasing the value of 6N137 load resistors and also try changing 6N137 LED drive current.
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Old 11th February 2008, 08:49 AM   #30
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Are you using TO247 mosfets? It will have significant capacitance between Drain/flange with ground (if the heatsink is grounded).
You can try putting aluminum oxide insulator (1-1.5mm thick) to lower this capacitance.
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