I have to identify the individual keys presses from a DTMF signal. There are three keys presses together as seen in the image. The signal has a sampling frequency of 8kHz. Each tone lasts between 0.1 and 0.2 of a second and there is a gap between tones of at least 0.05 of a second. However, there is random jitter in the timing so the actual timing will be unpredictable. The level of noise on the output is given by the signal to noise ratio of, SNR. I am unable to proceed with this.