The document describes implementing DTMF (dual-tone multi-frequency) detection using the Goertzel algorithm in an FPGA. It proposes using the Goertzel algorithm as an area-efficient solution compared to using an ASIC or FFT. The key steps of the Goertzel algorithm are described for detecting the presence of DTMF tones from a signal. The algorithm is further optimized by modifying it based on the matched filter concept.

4. DTMF detection by Goertzel technique DTMF test signal generator Hex key pad Additive white Gaussian noise Chipscope ILA Chipscope ICON JTAG

8. Goertzel algorithm implementation Conventional FIR filter structure requires higher order for narrow band Pass filtering, Goertzel algorithm extracts the peak of the signal at the specified frequency component with less hardware

12. Goertzel Algorithm Implementation

15. DTMF detection by Goertzel technique DTMF test signal generator Hex key pad Additive white Gaussian noise Chipscope ILA Chipscope ICON JTAG

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19. Basic Principle of DDFS