Power Cepstrum

This is an app that display a graph of frequency spectrum and cepstrum. By looking at the peak in the cepstrum graph, you can determine the fundamental frequency easily. Touch the graph at point of interest to show its frequency.

The application of Cepstrum has been widely used in engineering (gear box fault analysis, turbine and motor diagnostic etc), acoustic, speech, lie detector, radar and medical imaging. This app makes it very convenient to apply cepsturm on your mobile phone without using any expensive or lab based equipment. For musical field, it is tested and work perfectly for piano, electric piano, organ, guitar, violin, trumpet, harp and vibraphone.

A simple test on the app:

1. Play a key eg. A4 (440Hz) on a keyboard, guitar or piano

2. See where is the greatest peak on the cepstrum graph

3. Touch the peak and the frequency 440Hz will appear.

Download and listen to your car engine, room air con and washing machine. By listening to their vibration, you can tell what is their normal working frequency. If you travel, use it to listen to your air plane frequency.

Note that the peak at bottom cepstrum graph corresponds to another peak at the frequency spectrum graph above. Both graphs are drawn to the same logarithm scale on the x axis for easy reference.

Have fun!