I have a project on a STM32F103 using the ADC.
I'm trying to make simple VU meter. I made a litle circuit (a resistor divisor and a decoupling capacitor) to put the audio signal into de uC. Becouse of the resistor I get 2048 counts for no audio input.
So, when I put audio to the systems I get my ADC sampling it around 2048. Now I want to convert 16 bits unsigned (but centered at 2048) to Q15 to use CMSIS FFT_Q15
Is there any CMSIS function to do that? Is there a simple way to do that?
Thank!
Hi,
This is a common characteristic of complex FFT on real signals, just have a look at the bin number (64 - 10), you should have the same magnitude.
Real signals have a symmetric spectrum at output of Complex FFT, you can try to search or read this.