whistle tune detection

hey guys,

I have a task to design an audio based system that detects a particular whistle tune. The program should be running all the time and response when the whistle is tuned.

I have bulit a microphone and amplifier circuit, and then use DAQ to acquire this signal into MATLAB, and now I need to do some analysis on the acquired data to detect it.

One of the whistle signal needed to be detected is in the following link: http://www7.chuantu.info/tupian/20/1333108416x2918527103.png The graph on the left is the useful part of the samples of the signal needed to be detected. The graph on the right is the FFT of the signal. As you can see, there are two or three significant frequency components in this whistle tune.

The DAQ will be getting signal and sample the signal all the time, this makes the analysis hard.

Anyone has any simple and good idea to solve this? I am new in signal processing, keep it simple please...

Thank you very much in advance. :)