search for signal of fixed duration and frequency

Hi , I have an audio signal which i have recorded , i need to determine if inside the recorded signal , i have a smaller signal with duration of 250 ms and frequency of 400 Hz. Which method should i use for it ?

[cob]

where disappeared the newer comments ?

Answer 1

[Luffy]

Do the fft of the audio signal. You'll get spikes at the frequencies present in your signal.

How to do fft: doc fft.

Doing fft tells you if there is a signal of 400 Hz in your audio,to know the duration pass your audio through a notch filter of 400 Hz