I would like to build a sinus frequency generator that can be controlled via an Arduino. Sinus frequency would be in the low frequency regime (below 100 Hz) with a voltage around 2.5 Volts peak to peak.
I will have to use the SPI interface SPI tutorial for other purposes at my Arduino. Therefore an external IC that can be controlled via SPI is not feasible.
Additionally I would like to avoid the DDS (Digital Direct Synthesis) possibility as I would like to externalize the frequency generation.
So perhaps the sinus generation should be made with some of the standard oscillators like Wien bridge etc.
Can somebody give me a link for a circuit that fulfills my requirements and that can be controlled with an Arduino Uno?
With control I mean:
- Frequency (this is not a must but a nice to have)
With "I would like to externalize the frequency generation" I mean: keep the programming logic inside Arduino clean of too much things, that a dedicated device can do better. If I use hardware instead of software, I expect to have a less fragile setup regarding timing. If other time critical extensions come up, I have more "headroom" for them.