Digital Audio Processor for Cellular Applications
Modems for cellular applications such as 2G GSM, 3G UMTS, or 4G LTE are software defined. A number of processor cores (CPUs) combined with Digital Signal Processors (DSPs) is connected with hardware accelerators and analog components. In such a setup voice processing undergoes several steps. These include an Analog to Digital Converter (ADC) which samples an electrical signal from a microphone into the digital domain and uses a standard digital audio interface (e.g. I²S) to transfer the samples to a voice codec processor. The latter filters and compresses the data. This is done on a CPU/DSP dedicated to voice processing alone. After voice codec processing the digital data is transferred to a channel encoding unit and subsequently enters the analog domain before being modulated and transmitted over an antenna terminal. Receiving voice data undergoes the same steps in inverted order and function.
In this project a hardwired voice codec processor for commonly used voice codecs in 2G/3G/4G voice communication shall be implemented on an ASIC. An attempt has been made in a previous ASIC project . An ASIC solution as opposed to a CPU/DSP solution decreases the amount of CPU/DSP cores in a cellular modem. At the same time, area requirements and power consumption can be drastically reduced. This project is a good way to learn digital ASIC design with a real world application in mind.
- Looking for 1-2 Semester/Master students
- Contact: Benjamin Weber
- Interest in audio processing
- 10% Theory
- 90% Implementation
 Sidclei da Silva, Andreas Ochsner. IC Design: Entwurf eines GSM Sprachsynthesechips. Semesterarbeit D-ITET ETH, TS 486. 2002.