by: AndWaves, LLC • 3
This real-time spectrogram covers the full 22 KHz audio bandwidth, the same as a compact disk (CD). No advertisements.
The output is a display in the form a waterfall plot that presents the frequency spectrum of the audio as it changes in time. Later points in time at at the bottom of the spectrogram.
The user may choose the signal intensity be plotted on a color or gray scale. Red represents a strong signal, blue a weak signal.
Semi-log and linear plots are selected through the Options menu in the upper right.
For the technical person...
This spectrogram collects 1024 samples at a sampling rate of 44,100 Hertz every 150 milliseconds. Each collection of 1024 samples corresponds to a single horizontal line in the display as shown in the screenshots. A moving horizontal line is added just ahead of the most recent horizontal line of data so the user can identify the latest data.
The feature graphic on the Android Marketplace shows the sound "fingerprints” of various activities, including those of cricket chirping. In some of these plots the phone is adding noise to the spectrogram. (Yes some phones make very soft sounds.)
Have fun looking at the “sound prints” of ordinary things. To learn more about frequency spectra see the one-page tutorial on our website, https://sites.google.com/a/andwaves.com/www/home/about-fourier-transforms