LTspice error con imported wave signals FFT

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santiaznarez

Joined Jul 18, 2020
5
Hello, I'm designing a PLL for frequencies between 68khz and 72khz. It works wonders with SFFM signals, and now I'm on the stage of testing it with wave files from Scilab.
I made an FM modulation with 70khz carrier, I double-checked that the signal was correctly modulated. But when I import this signal to LTspice, I get something really weird on the signal FFT.
It's like the frequencies around 70Khz are doubled around 80Khz. I'm starting to think is a problem with LTspice. Does anyone have an idea of what may be going wrong? I also analyzed the spectrum of the signal on Audacity, and the peaks around 80Khz arent there, LTspice is for sure adding them.
I uploaded an image of the spectrum on spice.
Thanks! Sorry for my bad English btw.
 

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Alec_t

Joined Sep 17, 2013
11,504
Can you upload your asc and wav files here? (You may need to change the wav file extension to, for example, txt if the site's software objects to wav format).
 

Thread Starter

santiaznarez

Joined Jul 18, 2020
5
Can you upload your asc and wav files here? (You may need to change the wav file extension to, for example, txt if the site's software objects to wav format).
Of course! I'm also uploading the spectrum analysis of Audacity(picture and txt), so that you can check that the wave has only frequencies around 70k. I'm not sure if I have uploaded the wave file correctly btw!Jumanji 4 Spectrum.png
 

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