I have been searching for a VCO with a sinewave output for use at low frequencies (in the audio band). Anyone know of a product which would do this off the shelf?
I am surprised at how difficult this is; the best I've found so far is probably the old 8038 function generator, which is OK but requires various trims for sinewave purity.
I wouldn't know where to look for a clean VCO in the audio band, but have you looked at using a part like the AD9912 DDS synthesizer for generating these tones? The DDS is a sine-wave generator and can synthesize very low frequencies. The amount of extreme oversampling should keep the spurious to a minimum. The SFDR at even 100 MHz is still quite good.
If you want a smaller, lower-power part, the AD9913 might be a good fit.
many thanks for your suggestion. I'll look into that, sounds interesting.
Please let me know how if this works well for you. The more I think about it, it should work well.
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