Hi,
I'm glad to report that the oscillator is working (very) well. I need sine and cosine (coexistent) together, that's why I implemented the biquad coupled sine oscillator.
The only problem is initializing sine AND cosine.
The osillator frequency should be set (or chosen) by user at program run-time. So I used Taylor series approximation for calculating start values, but it's precision here is different for sine and cosine.
Secondly, there is an another problem while using fixed point data: start angle (or delta) must be <1. I tried to use formulas like sin(x)=sin(180-x) and cos(x)=-cos(180-x) plus angle addition formulas for 45 degrees angles. I think init values calculation lost more precision after using it.
Does anyone have another idea for init calculation?
Thanks