DESIGN AND IMPLEMENTATION OF AUDIO CODEC INTERFACE, DTMF GENERATION, AND DTMF DETECTION FOR SCRAMBLING KEY TRANSMISSION ON FPGA-BASED SECURE VOICE COMMUNICATION DEVICE

• Main Author: Aradhana Sahadewa, Lingga
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/87717
• Institution: Institut Teknologi Bandung

The increasing need for secure voice communication has driven the development of various encryption techniques to protect sensitive information. This document presents an FPGA-based solution for real-time secure voice communication utilizing dual-tone multi-frequency (DTMF) signals for scrambling key transmission. The proposed system utilizes Direct Digital Synthesis (DDS) for accurate DTMF tone generation and the Goertzel algorithm for efficient frequency detection. Both DTMF generator and detector are implemented on the Terasic® DE10-Standard FPGA with an integrated WM8731 audio codec interface to facilitate analog-to-digital and digital-to-analog voice signal processing. This system design ensures low hardware resource utilization, making it suitable for resource-constrained environments, while maintaining computational time from increasing significantly. Experimental results demonstrate successful generation, transmission, and detection of DTMF tones with an accuracy rate of 83.3%. The obtained results can be further improved by modifying the parameters used, thus ensuring better system reliability in transmitting scrambling keys through analog voice channels. This work provides a foundation for future research regarding real-time analog voice encryption key distribution using DTMF signals.