VLSI Digital
Filters
Our research in this area
has been directed towards design of concurrent algorithms and architectures
for VLSI digital filters. In 1960s and 1970s, digital signal processing
algorithms were implemented using the available microprocessors which executed
the algorithms sequentially. Therefore, there was no motivation for designing
concurrent signal processing algorithms, which could exploit pipelining
or parallelism. The advances in VLSI technology and parallel processing
has changed our thinking style for signal processing algorithm design.
Our research efforts in designing concurrent algorithms have been directed
towards transforming existing non-concurrent algorithms into concurrent
forms as well as designing new algorithms which are inherently concurrent.
We have developed look-ahead transformation, decomposition,
and incremental computation techniques to create pipelining and
parallel processing in signal processing algorithms. In addition, we have
proposed sum, delay, and product relaxed look-ahead
techniques to design inherently pipelined adaptive digital filters. We
have addressed design of pipelined and parallel recursive digital filters,
recursive lattice digital filters, recursive wave digital filters, LMS
adaptive digital filters, adaptive lattice digital filters, two-dimensional
recursive digital filters, and rank-order and stack digital filters. We
have also examined finite word-length effects in these filters for fixed-point
hardware implementations. Our approaches introduced pipelining in these
algorithms. Pipelining of recursive digital filters was considered impossible
before. For the first time, we demonstrated feasibility of pipelined stable
recursive digital filters. For the first time, we also introduced pipelined
architecture topologies for various forms of adaptive filters. For recursive
least square (RLS) adaptive filters, we showed that these structures can
be easily pipelined by using our proposed Scaled TAngent Rotation
(STAR) rather than the common Given's rotation. The STAR rotation is approximately
orthogonal as opposed to exactly orthogonal. Recently we have demonstrated
that by using Annihilation Reordering Look-Ahead recursive least square
(RLS) adaptive filters can also be pipelined based on Givens rotation;
these filters maintain exact orthogonality. Truly orthogonal IIR recursive
filters have also been developed. These structures provide excellent roundoff
noise properties.
Selected
Publications
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N.R. Shanbhag and K.K. Parhi, Pipelined Adaptive Digital Filters, Kluwer
Academic Publishers, 1994.
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J.-G. Chung and K.K. Parhi, Pipelined Lattice and Wave Digital Recursive
Filters, Kluwer Academic Publishers, 1996.
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K.K. Parhi and D.G. Messerschmitt, "Concurrent Cellular VLSI Adaptive
Filter Architectures", IEEE Transactions on Circuits and Systems, Vol.
CAS-34, No. 10, October 1987, pp. 1141-1151.
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K.K. Parhi, and D.G. Messerschmitt, "Concurrent Architectures for Two-Dimensional
Recursive Digital Filtering", IEEE Trans. on Circuits and Systems,
Vol. CAS-36(6), June 1989, pp. 813-829.
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K.K. Parhi, and D.G. Messerschmitt, "Pipeline Interleaving and Parallelism
in recursive Digital Filters, Part I: Pipelining using Scattered Look-Ahead
and Decomposition", IEEE Transactions on Acoustics, Speech, and Signal
Processing, Vol. 37(7), July 1989, pp. 1099-1117.
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K.K. Parhi, and D.G. Messerschmitt, "Pipeline Interleaving and Parallelism
in recursive Digital Filters, Part II: Pipelined Incremental Block Filtering",
IEEE Transactions on Acoustics, Speech, and Signal Processing, Vol.
37(7), July 1989, pp. 1118-1135.
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K.K. Parhi, "Finite Word Effects in Pipelined Recursive Filters", IEEE
Trans. on Signal Processing, Vol. 39, No. 6, June 1991, pp. 1450-1454.
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K.K. Parhi, "Pipelining in Algorithms with Quantizer Loops", IEEE Trans.
on Circuits and Systems, Vol. 38, No. 7, July 1991, pp. 745-754.
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N.R. Shanbhag and K.K. Parhi, "A Pipelined Adaptive Differential Vector
Quantizer for Low-Power Speech Coding Applications", IEEE Trans. on Circuits
and Systems, Part II: Analog and Digital Signal Processing, 40(5),
pp. 347-349, May 1993.
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N.R. Shanbhag, and K.K. Parhi, "A Pipelined Adaptive Lattice Filter
Architecture", IEEE Trans. on Signal Processing, 41(5), May 1993,
pp. 1925-1939
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K.J. Raghunath, and K.K. Parhi, "Parallel Adaptive Decision Feedback
Equalizers", IEEE Transactions on Signal Processing, 41(5), May
1993, pp. 1956-1961.
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N.R. Shanbhag, and K.K. Parhi, "Relaxed Look-Ahead Pipelined LMS Adaptive
Filters and Their Application to ADPCM Coder", IEEE Transactions on Circuits
and Systems, Part II: Analog and Digital Signal Processing, Vol. 40(12),
December 1993, pp. 753-766.
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J.-G. Chung, and K.K. Parhi, "Pipelining of Lattice IIR Digital Filters",
IEEE Transactions on Signal Processing, 42(4), pp. 751-761, April
1994.
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L.E. Lucke, and K.K. Parhi, "Parallel Processing Architectures for Rank-Order
and Stack Filters", IEEE Transactions on Signal Processing, 42(5),
pp. 1178-1189, May 1994.
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N.R. Shanbhag, and K.K. Parhi, "Finite Precision Analysis of the ADPCM
Coder", IEEE Transactions on Circuits and Systems-Part II: Analog and Digital
Signal Processing, 41(5), pp. 364-368, May 1994.
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N.R. Shanbhag, and K.K. Parhi, "Corrections to "Finite Precision Analysis
of the ADPCM Coder"", IEEE Transactions on Circuits and Systems-Part II:
Analog and Digital Signal Processing, 41(7), pp. 493, July 1994.
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G.B. Adams III, E.J. Coyle, L. Lin, L.E. Lucke, and K.K. Parhi, "Input
Compression and Efficient VLSI Architectures for Rank-Order and Stack Filters",
Signal Processing, August 1994.
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N.R. Shanbhag, and K.K. Parhi, "Pipelined Adaptive DFE Architectures
using Relaxed Look-Ahead", IEEE Trans. on Signal Processing, 43(6),
pp. 1368-1385, June 1995
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J.-G. Chung and K.K. Parhi, "Scaled Normalized Lattice Digital Filters",
IEEE Trans. on Circuits and Systems, Part - II: Analog and Digital Signal
Processing, 42(4), pp. 278-282, April 1995.
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J.-G. Chung, H. Kim and K.K. Parhi, "Pipelined Lattice WDF Design for
Wideband Filters", IEEE Trans. on Circuits and Systems, Part - II: Analog
and Digital Signal Processing, 42(9), pp. 616-618, September 1995
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K.J. Raghunath, and K.K. Parhi, "Pipelined RLS Adaptive Filtering using
Scaled Tangent Rotations (STAR)", IEEE Transactions on Signal
Processing, 44(10), pp. 2591-2604, October 1996
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K.J. Raghunath and K.K. Parhi, "Finite Precision Error Analysis of QRD-RLS
and STAR-RLS Adaptive Filters", IEEE Transactions on Signal Processing,
45(5), pp. 1193-1209, May 1997
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Y. Li and K.K. Parhi, "STAR Recursive Least Square Lattice Adaptive
Filters", IEEE Trans. on Circuits and Systems, Part II: Analog and Digital
Signal Processing, 44(12), pp. 1040-1054, December 1997
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J.-G. Chung and K.K. Parhi, "Pipelining of Orthogonal Double-Rotation
Digital Lattice Filters", Proc. of the 27th Asilomar Conf. on Signals,
Systems, and Computers, pp. 1613-1617, Nov. 1-3, 1993, Pacific Grove (CA).
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N.R. Shanbhag and K.K. Parhi, "A Pipelined Kalman Filter Architecture",
Proc. of the 27th Asilomar Conf. on Signals, Systems, and
Computers, pp. 1225-1229, Nov. 1-3, 1993, Pacific Grove (CA)
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J.-G. Chung and K.K. Parhi, "Synthesis and Pipelining of Ladder Wave
Digital Filters", Proc. of the 1995 IEEE Int. Symp. on Circuits and
Systems, pp. 77-80, Seattle, May 1995.
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J.P. Ma, K.K. Parhi and E.F. Deprettere, "Pipelining of Cordic Based
IIR Digital Filters", Proc. of IEEE Int. Conf. on Acoustics, Speech and
Signal Processing, pp. 643-646, Munich, April 1997
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H. Kim, J.-G. Chung and K.K. Parhi, "Low-Noise Implementation Technique
for Pipelined Filters with Crowded Poles", Proc. of IEEE Int. Symp. on
Circuits and Systems, pp. 2196-2199, Hong Kong, June 1997
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J. Ma, E.F. Deprettere and K.K. Parhi, "Pipelined Cordic Based QRD-RLS
Adaptive Filtering Using Matrix Look-Ahead" Proc. of 1997 IEEE Workshop
on Signal Processing Systems: Design and Implementation,
pp. 131-140, Leicester, U.K., Nov. 1997
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J. Ma, K.K. Parhi, and E.F. Deprettere, "Pipelined Cordic Based QRD-MVDR
Adaptive Beamforming", in Proc. of IEEE Int. Conf. on Acoustics, Speech
and Signal Processing, pp. 3025-3028, May 1998, Seattle
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J. Ma, K.K. Parhi, and E.F. Deprettere, "High-Speed Cordic Based Parallel
Weight Extraction For QRD-RLS Adaptive Filtering", Proc. of IEEE Int. Symp.
on Circuits and Systems, pp. V-245-V-248, Monterey, May 31 - June 3, 1998
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J. Ma, K.K. Parhi, G.J. Hekstra, and E.F. Deprettere, "Efficient implementations
of Cordic-based IIR digital filters using fast orthonormal micro-rotations,
Proc. of the SPIE Advanced Signal Processing Algorithms, Architectures,
and Implementations VIII, 1998 Int. Symp. on Optical Sci., Eng. and Instrumentation,
July 19-24, 1998, San Diego (CA)
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J. Ma and K.K. Parhi, "High-Speed VLSI State-Space Orthogonal IIR Digital
Filters Using Matrix Lookahead", Proc. of 1998 IEEE Workshop on Signal
Processing Systems: Design and Implementations (SiPS), Oct. 8-10, 1998,
Boston
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A. Shalash and K.K. Parhi, "Three-Dimensional Carrierless AM/PM Line
Code for Unshielded Twisted Pair Cables", Proc. of IEEE Int. Symp. on
Circuits and Systems, pp. 2136-2139, Hong Kong,
June 1997 (Invited Talk)
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A. Shalash and K.K. Parhi, "Three-Dimensional Equalization for the 3-D
QAM System with Strength Reduction", Proc. of IEEE Int. Symp. on Circuits
and Systems, pp. IV-453-IV-456, Monterey, May 31 - June 3, 1998
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A. Shalash and K.K. Parhi, "Power Efficient FIR Folding Transformation
for Wireline Digital Communications", Proc. of 1998 Asilomar Conf. on
Signals, Systems and Computers, Nov. 1-4, 1998, Pacific Grove (CA)
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