How can I output a simple sine wave?

[mikkkkky]

Hi,
is it possible to have a simple example of how generate a sine wave to the dac of Audioinjector stereo sound card?
The idea is to read the microphone signal, make the fft of the input signal, analyze and find the frequency with the maximum value and output a sine wave with the frequency found by fft analysis.
It should be done with the possible lowest latency and inside a continuous loop. I expected to have the main frequency of the input signal located below 300-500 Hz.
Someone has an idea of how to proceed?
Thank you

[wh7qq]

The software package "Audacity" has the ability to generate a sound wave of a desired audio frequency and save it to a file. Generate>Tone will get you there from the Audacity top menu.