ESCOLA TÈCNICA SUPERIOR D’ENGINYERIA ELECTRÒNICA I INFORMÀTICA LA SALLE PROJECTE FI DE CARRERA ENGINYERIA EN TELECOMUNICACIÓ Estudio, Analisis e implementación del Vocoder mediante procesado digital de la señal ALUMNE PROFESSOR PONENT Daniel Alonso Laguna Xavier Sevillano Domínguez ACTA DE L'EXAMEN DEL PROJECTE FI DE CARRERA Reunit el Tribunal qualificador en el dia de la data, l'alumne D. Daniel Alonso Laguna va exposar el seu Projecte de Fi de Carrera, el qual va tractar sobre el tema següent: Acabada l'exposició i contestades per part de l'alumne les objeccions formulades pels Srs. membres del tribunal, aquest valorà l'esmentat Projecte amb la qualificació de Barcelona, VOCAL DEL TRIBUNAL VOCAL DEL TRIBUNAL PRESIDENT DEL TRIBUNAL 2 DANIEL ALONSO LAGUNA VOCODER ANALYSIS AND IMPLEMENTATION TROUGH DIGITAL SIGNAL PROCESSING Canoas, 2009 3 DANIEL ALONSO LAGUNA VOCODER ANALYSIS AND IMPLEMENTATION TROUGH DIGITAL SIGNAL PROCESSING Trabalho de Conclusão apresentado para a banca examinadora do curso de Engenharia de Telecomunicações do Centro Universitário La Salle – Unilasalle, como exigência parcial para a obtenção do grau de Bacharel em Engenharia de Telecomunicações, sob orientação do Professor Ms. Alexandre Gaspary Haupt. CANOAS, 2009 4 AGRADECIMENTOS À mis padres, por el apoyo incondicional y darme la posibilidad de estudiar todo lo que he querido. A mi novia por el cariño, confianza y paciencia que siempre tuvo con mis labores de eterno estudiante, espero que el fin de mis dias de estudiante acaben pronto pero que nunca deje de aprender contigo. A los profesores a ambos lados del ‗charco‘ que me ayudaron, influenciaron y siempre me dieron algo de luz cuando todo estaba negro. A La Salle como entidad educativa internacional, por darme la posibilidad de estudiar en Brasil. Especialmente a los departamentos de relacciones internacionales de La Salle en Barcelona y Canoas que fueron los que realemente hicieron esto posible. A la Generalitat de Catalunya y al Banco Santander por darme el apoyo economico necesario para llevar esta aventura a acabo. 5 Dedico este trabajo a mi família: especialmente a mis abuel@s que supieron transmitir a mis padres los valores con los que me educaron, y que lamentablemente nos fueron dejando mientras me formaba como ingeniero, y sobretodo como persona. A mi novia Judith, que le costó bien poco liarse la manta a la cabeza y acompañarme hasta Brasil para realizar el proyecto final de carrera. No hubirera sido lo mismo sin tí, gracias de corazón. Os quiero a tod@s con locura. 6 ABSTRACT Audio effects have been a recurring technique ever since studio recordings developed the mixing console in the fifties, nowadays every music producer know that they are essential. Initially they were developed to simulate natural effects of music, like a choir of singers or the natural reverberation of a church, which is one of the main characteristics of Gregorian sing. In the 70's these effects were simulated with electronic devices, but in the 80's the digital revolution arrived and in the 90's this became an affordable reality for every kind of musician. Actually with computer software is really easy to produce a music recording with a extremely low budget. This work consists in the analysis and the implementation of a Vocoder special effect, (not the compression device) in different platforms through different techniques studied along this project. Starting with simulations on Matlab and Simulink with the final objective to implement one real time vocoder on Texas Instruments TM320C5416 DSP board Keywords: Audio Effects; Digital Signal Processing; Vocoder. 7 LIST OF ILUSTRATIONS FIG. 1 – HOMER DUDLEY .............................................................................................. 14 FIG. 2 –FORMANT FREQUENCIES FOR DIFFERENT VOWELS .............................................. 15 FIG. 3 – PRESENTATION OF THE VODER IN 1939 ............................................................ 16 FIG. 4 – VODER‘S SCHEMATIC CIRCUIT .......................................................................... 17 FIG. 5 –VODER´S BLOCK DIAGRAM................................................................................. 18 FIG. 6 –VODER USED TO PITCHSHIFT A VOICE SIGNAL ...................................................... 19 FIG. 7 – TWO OF THE FIRST RECORDINGS TO USE VOCODER-LIKE EFFECTS: SONOVOX ....... 20 FIG. 8 – PERFORMER USING SONOVOX .......................................................................... 20 FIG. 9 – ARTIFICIAL LARYNGES ...................................................................................... 21 FIG. 10 – PETER FRAMPTON‘S TALK BOX ...................................................................... 22 FIG. 11 – GHETTO TALK BOX INSIDE A TOILET PLUNGER ................................................. 23 FIG. 12 – EARLY 1970S VOCODER, CUSTOM BUILT FOR ELECTRONIC MUSIC BAND KRAFTWERK ......................................................................................................... 25 FIG. 13 – TMS320VC5416 BOARD COMPONENT DESCRIPTION ....................................... 28 FIG. 14 – TMS320VC5416 FUNTIONAL BLOCK DIAGRAM ............................................... 29 FIG. 15 – PIONEER DM DV5 MICROPHONE .................................................................... 39 FIG. 16 – SONY MDR XD100 HEADPHONES ................................................................. 40 FIG. 17 – CODE COMPOSER STUDIO MAIN WINDOW ........................................................ 41 FIG. 18 – TI DSP THIRD PARTY SUPPORT ..................................................................... 47 FIG. 19 – MATLAB MAIN WINDOW AND GRAPHS ............................................................... 49 FIG. 20 – AUDACITY EDITING SOUND WINDOW ................................................................ 52 FIG. 21 – 3XOSC MAIN PARAMETER CONFIGURATION WINDOW ........................................ 56 FIG. 22 – VOCODER PARAMETER CONFIGURATION WINDOW ............................................. 58 FIG. 23 – KORG VOCODER VC10 ................................................................................ 61 FIG. 24 – SIBILANT SOUND OF AN S ............................................................................... 63 FIG. 25 – PLOSIVE SOUND OF A P .................................................................................. 64 FIG. 26 – SPECTRUM OF AN S ....................................................................................... 64 FIG. 27 – SPECTRUM OF A P ......................................................................................... 65 FIG. 28 – SPECTRUM OF AN O ...................................................................................... 65 FIG. 29 – ZOOM INTO THE SPECTRUM OF AN O ............................................................... 66 FIG. 30 – BASS DRUM SPECTRUM ................................................................................. 67 FIG. 31 – SNARE DRUM SPECTRUM ............................................................................... 67 FIG. 32 – LOW TOM DRUM SPECTRUM .......................................................................... 67 FIG. 33 – 3XOSC SAWTOOTH CONFIGURATION .............................................................. 69 FIG. 34 – 3XOSC SAWTOOTH DRY PLOTTED SIGNAL ...................................................... 69 FIG. 35 – 3XOSC SAWTOOTH DRY SPECTRUM ............................................................... 70 FIG. 36 – 3XOSC SAWTOOTH WITH FLANGER PLOTTED SIGNAL ..................................... 70 FIG. 37 – 3XOSC SAWTOOTH WITH FLANGER+DELAY PLOTTED SIGNAL ....................... 71 FIG. 38 – 3XOSC SAWTOOTH SPECTRUM WITH FLANGER+DELAY ............................... 72 FIG. 39 – 3XOSC STRING SPECTRUM WITH/WITH-OUT FLANGER+DELAY ................... 72 FIG. 40 – VOCODER SIMPLE BLOCK DIAGRAM ................................................................ 73 FIG. 41 – PAIA VOCODER BLOCK DIAGRAM ................................................................... 75 FIG. 42 – FILTER BANK INTERPRETATION VS. FOURIER TRANSFORM INTERPRETATION ....... 78 FIG. 43 – HANNING WINDOW ........................................................................................ 79 FIG. 44 – FFT (BLUE) VS. BANK FILTER (RED) NUMBER OF MULTIPLICATIONS ................. 80 8 FIG. 45 – SPECTRAL ENVELOPE CORRECTION ............................................................... 82 FIG. 46 – DB MAGNITUDE FREQUENCY RESPONSE OF VARIOUS WINDOWS (A) BARTLETT, (B) HANNING, (C) HAMMING, (D) BLACKMAN ................................................................. 88 FIG. 47 –FFT SEGMENTS OVERLAPPED ......................................................................... 89 FIG. 48 – MERGING FFT INTO AVERAGED BIGGER BANDS ................................................ 90 FIG. 49 – TIME PLOT OF THE 3 SIGNALS INVOLVED IN THE VOCODER ................................. 92 FIG. 50 – TIME PLOT OF A POORER VOCODED SIGNAL ...................................................... 93 FIG. 51 – TIME PLOT OF DRUMS VOCODING .................................................................... 94 FIG. 52 – SPECTRUM OF THE ORIGINAL VOICE ................................................................ 95 FIG. 53 – SPECTRUM OF VOCODER‘S OUTPUT ................................................................ 96 9 LIST OF TABLES TABLE 1– 9-BAND DESIGN FOR THE BANDPASS FILTER ..................................................... 74 TABLE 2– SUBJECTIVE PERFORMANCE OF MATLAB VOCODER .........................................