wip
Member
Hi,
I am generating a Pulse Width Modulation with my microcontroller (fix at 329hz). I am trying to transform, as much as possible, this PWM square signal to a sine AC signal. I am using a passive low pass filter and a electrolytic capacitor for AC coupling. My problem is the AC coupled signal is offset towards the positive side of the DC:
It is not that much, but it bothers me. Should I use a bigger capacitor or a lower? Right now, it's a 1uf. As for the sine, as you can see I am not there yet, it's more like a triangle. But I guess with the right combination of resistor and capacitor (and the fact that my frequency is fixed) I should be able to get a decent sine?
Finally, I am feeding the output of the AC coupled signal in a LM386, I must use an op-amp in voltage follower mode to avoid affecting my low pass or maybe I can choose the resistor and capacitor when the signal is connected to the LM386 (taking in consideration the resistance of the input pin of the amplifier)?
Thanks
I am generating a Pulse Width Modulation with my microcontroller (fix at 329hz). I am trying to transform, as much as possible, this PWM square signal to a sine AC signal. I am using a passive low pass filter and a electrolytic capacitor for AC coupling. My problem is the AC coupled signal is offset towards the positive side of the DC:
It is not that much, but it bothers me. Should I use a bigger capacitor or a lower? Right now, it's a 1uf. As for the sine, as you can see I am not there yet, it's more like a triangle. But I guess with the right combination of resistor and capacitor (and the fact that my frequency is fixed) I should be able to get a decent sine?
Finally, I am feeding the output of the AC coupled signal in a LM386, I must use an op-amp in voltage follower mode to avoid affecting my low pass or maybe I can choose the resistor and capacitor when the signal is connected to the LM386 (taking in consideration the resistance of the input pin of the amplifier)?
Thanks