Hi,

I need to design a low cost digital audio function generator. For the sinewave generation I would use a lookup table. To keep the control digital I need to scale (modulate) the peak sine values in software and softare PWM. Cannot use a PGA for cost restriction.
What is the best principal for that ?

I am restricted in terms of PIC throughput considering the soft pwm and other housekeeping functions. I must use a PIC16 @ 20MHz series to keep down the cost lower. So calculating the sine values on the fly (when doing a modulation) may eat up to much cycles to fit within the update routine

Please guide if it is at all possible and how ?