Using Spectrum analyzer in Simulink

Howdy,

So I'm using Simulink to look at the frequency spectrum of an audio file and I'm having a hard time understanding the output plot. The plot shows frequencies higher than 20kHz which is beyond what human can hear. Am I wrong to expect the audio frequency to be within what we can listen to? Thanks in advance!

Answer 1

[Darshan Ramakant Bhat]

As you can see the power is around -50dBm (10^-8 watt) which is very very less. So the effective signal strength is contained only within 3KHz. To see frequencies only within 3KHz, you can uncheck the "Full frequency span" and then set the span as 3KHz.

[Astro]

Hi there,

Thanks for responding. My confusion was why the plot showed frequencies higher than 20kHz which is the limit of our hearing. This input signal wave is an mp3 file. My main goal is to pass the signal through a series of filters and I'm currently working on finding the passbands for the filters so I just want to make sure that what plotting is correct.

Thanks!