Hi guys, I am designing a function generator (adjustable frequency, triangle, square, sine) for a university project. The design is supposed to be using fundamentals, so no dedicated chips. I have done the triangle and square waves using a couple of current sources, comparators, capacitor (will post up the design later just to check it looks alright). Only have +-6V on the rails and need to output a +-3V signal.
My current problem is generating the sine wave. I know that you can use a low pass filter so that you just have the fundamental frequency, but how do you set up the filter so that the resonant frequency changes if you change the frequency of the waveform. Ie how do you tune the integrator to work from 20Hz - 20kHz?
I have looked around and the only fundamental design I could find was this circuit:
which I dont understand how its produces a sine. Is this just a differential amp? Tried to simulate it but couldnt get it working.
Thanks in advance
My current problem is generating the sine wave. I know that you can use a low pass filter so that you just have the fundamental frequency, but how do you set up the filter so that the resonant frequency changes if you change the frequency of the waveform. Ie how do you tune the integrator to work from 20Hz - 20kHz?
I have looked around and the only fundamental design I could find was this circuit:
which I dont understand how its produces a sine. Is this just a differential amp? Tried to simulate it but couldnt get it working.
Thanks in advance