openbench_fgen
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openbench_fgen [2007/04/12 21:18] ladyada created |
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| - | ====== what ====== | ||
| - | A completely open design for a function/waveform generator: hardware, firmware, software | ||
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| - | ====== Notes & stuff ====== | ||
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| - | ===== Waveform generation ===== | ||
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| - | Waveforms we want (in order of importance) | ||
| - | * Sine wave | ||
| - | * Square wave (with variable PWM) | ||
| - | * Triangle wave | ||
| - | * Sawtooth (possibly a modification of triangle wave???) | ||
| - | * arbitrary waveform (sync, envelopes, etc) | ||
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| - | Frequency range: | ||
| - | * 1 Hz or lower | ||
| - | * 100 KHz or higher | ||
| - | * 1mHz -> 10MHz is ideal | ||
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| - | ==== Generator tech ==== | ||
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| - | Two options for chip 'styles' is the all-in-one oscillator (ICL3038, etc) +PLL or DDS | ||
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| - | === Oscillators === | ||
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| - | All-in-one is nice, except that the [[http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1257|MAX038]] is completely unavailable. And the [[http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=34972|XR2206]] kinda sucks. Also you'll need a PLL system to tune it. | ||
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| - | === DDS === | ||
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| - | Direct-Digital-Synthesis, currently popular. Basically: wavetable + 24 or 32 bit adder and sampling above nyquist to get precision waveforms. | ||
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| - | Pros: digital, precise, no PLL needed | ||
| - | Cons: hard to get high frequencies because of oversampling | ||
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| - | Either roll your own or buy off the shelf ([[http://www.analog.com/en/subCat/0,2879,770%255F843%255F0%255F%255F0%255F,00.html|basically from AD]]) | ||
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| - | == Off the shelf, AD parts == | ||
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| - | They come with sync out, very very high speeds. But only sine and square out, and in small packages (TSSOP). | ||
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/home/ladyada/public_html/wiki/data/attic/openbench_fgen.1176412696.txt.gz · Last modified: 2016/01/28 18:05 (external edit)
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