This was the Guitar Tuner demo from MATLAB Expo 2011. It receives analoginput from the sound card, and calculates the frequency using autocorrelation. This information is then displayed graphically, so that one may use it to tune an input pitch.
Teja Muppirala (2020). Guitar Tuner Demo from MATLAB Expo 2011 in Tokyo (https://www.mathworks.com/matlabcentral/fileexchange/33605-guitar-tuner-demo-from-matlab-expo-2011-in-tokyo), MATLAB Central File Exchange. Retrieved .
Fixed a typo in the title.