8.6 Complex input

Complex input

Once the program was successfully developed, it was run on a recognizable tune: the first four measures of “Twinkle Twinkle Little Star.” Again, the traditional spectrogram, the reassigned spectrogram, and the MATLAB output are shown below. Each note of the song was correctly identified and output by the system.

Traditional spectrogram

Fig 1 The traditional “smeared” spectrogram of “Twinkle Twinkle Little Star”

Reassigned spectrogram

Fig 1 The reassigned spectrogram of “Twinkle Twinkle Little Star”

System output

Again, the system correctly identified all of the notes of the input signal without error. The first four measures of “Twinkle Twinkle Little Star” are as follows:

Here is the MATLAB output:

Fig 3 The MATLAB output accurately identifying each note