Implementing extreme upsampling filters with a multiply-less architecture
Name
Laffely-2009-Implementing extreme upsampling filters with a multiply-less architecture.pdf
Size
12.29 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Hillger, Jason J.
Timmerman, Chayil S.
Ramakrishnan, Balasubramanian
Laffely, Andrew
Yao, Huan
Date Issued
January 2010
Journal
IEEE Military Communications Conference, 2009. MILCOM 2009
Publisher
Institute of Electrical and Electronics Engineers
Citation
Laffely, A. et al. “Implementing extreme upsampling filters with a multiply-less architecture.” Military Communications Conference, 2009. MILCOM 2009. IEEE. 2009. 1-5. © 2010 Institute of Electrical and Electronics Engineers.
Version
Final published version
Abstract
For ease of implementation, communications systems have been steadily converted to digital implementations. FPGA technologies and high-quality, high-speed DACs have enabled this trend. While this is commonly done for modern high bit-rate communications systems, legacy systems like the MIL-STD-188-165A modem are not often considered. One issue is the need to up-sample these slower standards by factors of tens of thousands in order to interface them with the modulation system. This paper presents an architectural case study on the implementation of a direct digital synthesis MIL-STD-188-165A modem. It briefly describes a multiply-less single stage filter architecture with unlimited up-sampling capabilities. The filter implements a Farrow type design. By selecting the appropriate filter coefficients from a set of look-up-tables (LUT) the filter can be designed to suppress harmonic distortion below the required filter mask. Mathematical evaluation of these properties proves that a reasonable size LUT of 1024x14 bits is sufficient to suppress harmonics below - 60 dB. A full analysis of harmonic suppression vs. LUT size is included to extend this work beyond the MIL-STD-188-165A case study.
MIT Department
Lincoln Laboratory
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1109/MILCOM.2009.5379811
