I'm trying to record analog values with a digital recorder. Basically I have a recorder and have 2 leads connected via the mic port. If I just apply regular voltage to the leads the recorder doesn't recognize the external mic and records with the internal mic. It seems as though the recorder will only read values through the external mic if there is a tone going through it. I know the Arduino can generate tones, but if possible I'd like to do this with a simple voltage to frequency converter IC like the Texas Instruments LM231 (http://www.ti.com/lit/ds/symlink/lm231.pdf
). My question is: if I convert voltage to frequency, is that the *same* thing as generating a tone (will it be readable)?