Update readme

README.md

@@ -34,6 +34,9 @@ Also see [Derek Jamison's demonstration](https://www.youtube.com/watch?v=iC5fBGw
 
 ![Flipper Zero running flipperscope - showing voltage measurements](photos/volt.jpg)
 
+In the following photo attached a MAX9814 electret microphone module to the flipper zero and used the spectrum
+analyser functionality, with an FFT window size of 1024 and played a 3kHz sine wave tone from a computer.
+
 ![Flipper Zero running flipperscope - showing spectrum analyser](photos/fft.jpg)
 
 ## Processing captures
@@ -72,3 +75,4 @@ plt.show()
 * STM32 DMA example
 * VREFBUF information - https://community.st.com/s/question/0D53W00001awIlMSAU/enable-and-use-vrefbuf-for-adc-measures
 * Relocating vector table - https://community.nxp.com/t5/i-MX-Processors/Relocate-vector-table-to-ITCM/m-p/1302304
+* Uses FFT algorithm from - https://www.algorithm-archive.org/contents/cooley_tukey/cooley_tukey.html