I've tested my CEM3340 VCO with waveshaper. It works fairly well. It has one major flaw:
Triangle frequency drops when changing pw from 50/50 to 90/10. This was expected for the Cem PWM, but it happens, and is even more pronounced, with my own pwm! I have tried buffering the supply lines (+/-15v) but it doesn't help
In general it is extremely sensitive to voltage changes, so my breadboard isn't exactly the ideal test platform. But it is annoying none the less.
Other than that:
- All waveforms work fine
- Linear FM works fine
- Hard sync works fine
- Cem Hard Sync works fine, but only with a 1nF cap in series with the input signal. Normal hard sync works without this (prob. because it already has a 220pF series cap) but also works WITH.
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| Saw wave, CEM Hard sync |
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| Saw wave, normal hard sync |
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| Saw wave, CEM Soft sync? Doesn't seem to work very well, not sure how it is supposed to work really (noone seems to know :-D) |
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| Triangle wave, CEM Hard sync |
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| Triangle wave, normal hard sync |
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| Triangle wave, CEM Soft sync. Again, it looks like CEM hard sync. Not sure what to expect. |
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