Cosine Modulated Filter Banks

• Main Author: Nord, Magnus
• Format: Others
• Language: English
• Published: Linköpings universitet, Institutionen för systemteknik 2003
• Subjects: Electronics; filter banks; DCT; implementation; FPGA; VHDL; DIT; DIF; Elektronik
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1641

The initial goal of this report was to implement and compare cosine modulated filter banks. Because of time limitations, focus shifted towards the implementation. Filter banks and multirate systems are important in a vast range of signal processing systems. When implementing a design, there are several considerations to be taken into account. Some examples are word length, number systems and type of components. The filter banks were implemented using a custom made software, especially designed to generate configurable gate level code. The generated code was then synthesized and the results were compared. Some of the results were a bit curious. For example, considerable effort was put into implementing graph multipliers, as these were expected to be smaller and faster than their CSDC (Canonic Signed Digit Code) counterparts. However, with one exception, they turned out to generate larger designs. Another conclusion drawn is that the choice of FPGA is important. There are several things left to investigate, though. For example, a more thorough comparison between CSDC and graph multipliers should be carried out, and other DCT (Discrete Cosine Transform) implementations should be investigated.