Signal processing

[Madhuribhosikar]

How do i ignore the harmonics in the signal? 

I have time Domain signal which I converted in frequency Domain. Before that i used Antialising filter(low pass filter) and then Standard PSD block. In the result i got harmonics of the generated frequency as well as some unnecessary frequency even when I generate different frequency. 

So i want only the generated frequency in the signal. I need to ignore it's harmonics. 

How do I ignore Harmonics? Is there any standard block Or any solution? 

Please help me. 

[Henrik_Volkers]

The DFT (FFT)  will convert your time domain signal into a frequency domain representation... with all the information buried in the time domain signal ... wanted or not 😄

If you only want the known(!) generated signals (I assume one ore more sines), why don't you try tone detection?

Or sine approximation?

What do you want to measure? (Transferfunctions?)

Some sample data would be nice 🙂

[paw510]

I don't understand what you are doing :

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Before that i used Antialising filter(low pass filter) and then Standard PSD block.

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Usually antialiasing comes after PSD (if PSD stands for phase sensitive detection here).  Then since the PSD will shift the spectrum to low (or zero) frequency the antialiasing cutoff can be easily set low enough to filter all harmonics of the baseband signal.  

Unless I'm completely mistaken about the purpose of the thing you're describing.

[Henrik_Volkers]

Maybe just turn dB off ... aaaand the harmonics looks muuuuch nicer ... 😄