Hello,
I'm trying to simulate my little class D circuit in Orcad and mesure the THD with the built-in function. My results are about 0.8% at 10kHz,6-7Watts. The strange thing is that my input(sinusoidal source) has THD about 0.003%(which is my goal pretty much). Is there any way to have a better sin an the input and is there any built in function to mesure A-weighted THD? Thnx in advance.
I'm trying to simulate my little class D circuit in Orcad and mesure the THD with the built-in function. My results are about 0.8% at 10kHz,6-7Watts. The strange thing is that my input(sinusoidal source) has THD about 0.003%(which is my goal pretty much). Is there any way to have a better sin an the input and is there any built in function to mesure A-weighted THD? Thnx in advance.
Hello,
There isn't exactly an option 'step size' but there are some other options you can do as you can see in attachment. These are the best you can do before converge problems occur and THD still remains at 0.001%.
There isn't exactly an option 'step size' but there are some other options you can do as you can see in attachment. These are the best you can do before converge problems occur and THD still remains at 0.001%.
I don't know how many periods you simulated but try at least 4 to five periods. And then there is another question: When you checked the THD of the sinusoidal source, were you simulationg the amp as well or did you just simulate the source in order to see its THD ?
Regards
Charles
Regards
Charles
Firstly, sorry for the forgotten attachment, here it is. I'm simulating the source without any other circuit(only with an 1Ω resistor). Even for more periods the THD remains the same. In the file .out there is the THD and the voltage of each harmonic. The voltages(apart from the center frequency) are about nanoVolts and I think it might be a simulation's limitation.
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