| 摘要 |
PURPOSE: A method of detecting a DTMF in a communication terminal is provided to use a band pass filter having two poles to reduce a frequency deviation in a receiving band, and to use a Goertzel algorithm to reduce calculations in a transmitting band, thereby efficiently detecting a DTMF tone. CONSTITUTION: A communication terminal operates a filtering coefficient. The terminal filters inputted data in a two-pole band pass filtering method by using the detected filtering coefficient, and performs a discrete Fourier transform process. The terminal detects energy for a two-pole band pass filtering result and a discrete Fourier transform energy. The terminal detects a DTMF tone by using the energy for the two-pole band pass filtering result and the discrete Fourier transform energy. The terminal compares the two energies. If the energy for the two-pole band pass filtering result is bigger, the terminal accepts the detected DTMF tone. If the discrete Fourier transform energy is bigger, the terminal rejects the detected DTMF tone.
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