--- title: Dual-Tone Multi-Frequency (DTMF) Decoding with the Goertzel Algorithm in Java canonical: https://0110.be/posts/Dual-Tone_Multi-Frequency_%28DTMF%29_Decoding_with_the_Goertzel_Algorithm_in_Java markdown_url: https://0110.be/posts/Dual-Tone_Multi-Frequency_%28DTMF%29_Decoding_with_the_Goertzel_Algorithm_in_Java.md id: 343 published_at: '2011-09-27T09:07:26Z' updated_at: '2013-12-05T18:19:15Z' author: Joren tags: - name: Code markdown_url: https://0110.be/tags/Code.md - name: HoGent markdown_url: https://0110.be/tags/HoGent.md - name: Java markdown_url: https://0110.be/tags/Java.md - name: TarsosDSP markdown_url: https://0110.be/tags/TarsosDSP.md --- # Dual-Tone Multi-Frequency (DTMF) Decoding with the Goertzel Algorithm in Java DTMF Goertzel in JAVAThe DSP library of Tarsos, aptly named TarsosDSP, now contains an implementation of the Goertzel Algorithm. It is implemented using pure Java. The [Goertzel algorithm](http://en.wikipedia.org/wiki/Goertzel_algorithm) can be used to detect if one or more predefined frequencies are present in a signal and it does this very efficiently. One of the classic applications of the Goertzel algorithm is decoding the tones generated on by touch tone telephones. These use [DTMF (Dual tone multi frequency)-signaling](http://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling). To make the algorithm visually appealing a Java Swing interface has been created(visible right). You can try this application by running the "Goertzel DTMF Jar-file":\[GoertzelDTMF.jar\]. The souce code is included in the jar and is avaliable as a separate "zip file":\[GoertzelDTMF_src.zip\]. The [TarsosDSP github page](https://github.com/JorenSix/TarsosDSP) also contains the source for the [Goertzel algorithm Java implementation](https://github.com/JorenSix/TarsosDSP/blob/master/src/be/hogent/tarsos/dsp/pitch/Goertzel.java). ![DTMF detection of 9](https://0110.be/files/photos/343/goertzel_DTMF_java_9.png) ![DTMF detection of 2](https://0110.be/files/photos/343/goertzel_DTMF_java_2.png) - [goertzel\_DTMF\_java\_7.png](https://0110.be/files/attachments/343/goertzel_DTMF_java_7.png) - [GoertzelDTMF.jar](https://0110.be/files/attachments/343/GoertzelDTMF.jar) - [GoertzelDTMF\_src.zip](https://0110.be/files/attachments/343/GoertzelDTMF_src.zip)