On Tue, 11 Mar 2008 17:48:18 +0100 "Rikard Bosnjakovic" wrote: > Since I never had the opportunity to play around with ADC and DAC's, I > got these MAX549-chips (dual 8-bit DAC) to be able to increase my > experience. Using a PIC, I wrote a quick code that outputs 0 up to 255 > (and then back to 0) to the DAC, getting a 5Hz "sinewave". If you send values from 0 to 255 and back, in a linear way, you will have a triangle wave. If you look up the theory, that is a sine wave plus (weaker) harmonics (multiples of the basic sine). If you really want a sine, you'll have to send values from a table, which contains the amplitudes of the sine. At 256 levels it will give you a quite good approximation of the sine (very little distorsion). To eliminate most of the noise, you can put a simple lowpass filter (a resistor + capacitor) calculated at twice or three times the wanted sine frequency. John -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist