Abstract
In this paper we develop a multiple-clock-cycle signal adaptive hardware design of an optimal nonstationary (time-varying) filtering system. The proposed design is based on the real-time results of time-frequency (TF) analysis and the estimation of instantaneous frequency (IF). It permits multiple detection of the local filter’s region of support (FRS) in the observed increment of time, resulting in the efficient filtering of multicomponent frequency modulated (FM) signals. The proposed design takes a variable number of clock (CLK) cycles–the only necessary ones regarding the highest quality of IF estimation–in different TF points within the execution. In this way it allows the implemented system to optimize the computational cost, as well as the time required for execution. Further, the proposed serial design optimizes critical design performances, related to the hardware complexity, making it a suitable system for real-time implementation on an integrated chip. Also, by applying the pipelining technique, it allows overlapping between different TF points within the execution, additionally improving the time required for time-varying filtering. The design has been verified by a field-programmable gate array (FPGA) circuit design, capable of performing filtering of nonstationary FM signals in real-time.
Similar content being viewed by others
Notes
Boundaries of each STFT auto-term’s domain coincide with the detection of \( {\left| {STF{T_x}\left( {n,k \pm i} \right)} \right|^2} < {S^2} \) around corresponding signal component. It means that \( {\left| {STF{T_x}\left( {n,k \pm i} \right)} \right|^2} \geqslant {S^2} \), for i = 0,1,…,L(n,k), in each point (n,k) from STFT auto-terms’ domains, whereas \( {\left| {STF{T_x}\left( {n,k \pm i} \right)} \right|^2} < {S^2} \) for ∀i should be satisfied otherwise. Therefore, L(n,k) takes variable values in different TF points: zero (L(n,k) = 0) outside STFT auto-terms’ domains and at their boundaries (in the case of non-noisy signal), the higher one inside these domains, and the maximum one (L m ) only in the central points of the widest domain(s). In the case of noisy signal, depending on the noise distribution and the S 2 selection, \( {\left| {STF{T_x}\left( {n,k \pm i} \right)} \right|^2} \geqslant {S^2} \) can be satisfied in the particular (n,k) points existing outside the STFT auto-terms’ domains. This implies the non-zero L(n,k) values in these points.
Parallel and hybrid designs minimize the total number of used memory locations, since the parallel one does not include LUT memory (of L m +2 locations), whereas the hybrid one includes LUT memory of only three locations (controls the execution in three CLKs by frequency point). In addition, the proposed signal adaptive design includes two input memories (used for storing the real and imaginary parts of input STFT samples), capacity of maximum N locations. However, note that the total number of used memory locations remains quite small in all considered cases.
References
Matz, G. & Hlawatsch, F. (2002). Linear time-frequency filters: Online algorithms and applications. In Papandreou-Suppappola, A. (Ed.), Applications in Time-Frequency Signal Processing (pp.205–271). CRC Press.
Zadeh, L. A. (1950). Frequency analysis of variable networks. Proceedings of IRE, 76, 291–299.
Kramer, M. L. & Jones, D.L. (1994). Improved time-frequency filtering using as STFT analysis-modification-synthesis method, Proc. IEEE-SP Int. Sym. Time-Frequency Time-Scale Analysis, Philadelphia, 264–267
Xia, X.-G., & Qian, S. (1999). Convergence of an iterative time-variant filtering based on discrete Gabor transform. IEEE Transactions on Signal Processing, 47(10), 2894–2899.
Feichtinger, H. G., & Strohmer, T. (Eds.). (1998). Gabor analysis and algorithms: Theory and applications. Boston: Birkhäuser.
Kozek, W. (1992). Time-frequency signal processing based on the Wigner-Weyl framework. Signal Processing, 29(10), 77–92.
Kozek, W. & Hlawatsch, F.(1992). A comparative study of linear and nonlinear time-frequency filters, In Proc. IEEE-SP Int. Sympos. Time-Frequency Time-Scale Analysis, Victoria, Canada, 163–166.
Shenoy, R. G., & Parks, T. W. (1994). The Weyl correspodence and time-frequency analysis. IEEE Transactions on Signal Processing, 42(2), 318–331.
Hlawatsch, F., Matz, G., Kirchauer, H., & Kozek, W. (2000). Time-frequency formulation, design and implementation of time-varying optimal filters for signal estimation. IEEE Transactions on Signal Processing, 48(5), 1417–1432.
Matz, G. & Hlawatsch, F.(2002). Linear time-frequency filters. In Time-Frequency Signal Analysis and Processing, Boashash, B. (ed.), Pretice Hall.
Gröchenig, K. (2001). Foundations of Time-frequency analysis. Birkhäuser.
Cohen, L. (1995). Time-frequency analysis. Prentice-Hall.
Zeevi, Y. Y., Zibulski, M., & Porat, M. (1998). Multi-window Gabor schemes in signal and image representations. In H. G. Feichtinger & T. Strohmer (Eds.), Gabor analysis and algorithms: Theory and applications (pp. 381–407). Boston: Birkhäuser.
Zibulski, M., & Zeevi, Y. Y. (1997). Discrete multiwindow Gabor-type transforms. IEEE Transactions on Signal Processing, 45(6), 1428–1442.
Zibulski, M., & Zeevi, Y. Y. (1997). Analysis of multiwindow Gabor-type schemes by frame methods. In Applied and Computational Harmonic Analysis, 4(4), 188–221.
Hlawatsch, F., & Kozek, W. (1994). Time-frequency projection filters and time-frequency signal expansions. IEEE Transactions on Signal Processing, 42(12), 3321–3334.
Claasen, T. A. C. M., & Mecklenbräuker, W. F. G. (1982). On stationary linear time-varying systems. IEEE Transactions on Circuits and Systems, 29(3), 169–184.
Matz, G. & Hlawatsch, F. (2002). Time-frequency projection filters: Online implementation, subspace tracking, and application to interference suppression. In Proceedings of IEEE International Conference on Acoustic, SPEECH, AND Signal Processing (ICASSP ’02)Fla. USA, 2(5), 1213–1216.
Golub, G. H., & Van Loan, C. F. (1996). Matrix computations (3rd ed.). Baltimore: Johns Hopkins University Press.
Boudreaux-Bartels, G. F. (1997). Time-varying signal processing using Wigner distribution synthesis techniques. In Mecklenbräuker, W. & Hlawatsch, F. (Eds.), The wigner distribution—theory and applications in signal processing, pp.269–317. Elsevier.
Hlawatsch, F. & Krattenthaler, W. (1997). Signal synthesis algorithms for bilinear time-frequency signal representation. In Mecklenbräuker, W. & Hlawatsch, F. (Eds.), The Wigner Distribution—Theory and Applications in Signal Processing, pp.135–209. Elsevier.
Stanković, L. J. (2000). On the time-frequency analysis based filtering. Annals of Telecommunications, 55(5/6), 216–225.
Stanković, S., Stanković, L. J., Ivanović, V. N., & Stojanović, R. (2002). An architecture for the VLSI design of systems for time-frequency analysis and time-varyin filtering. Annals of Telecommunications, 57(9/10), 974–995.
Papoulis, A. (1997). Signal analysis. New York: McGraw-Hill.
Ivanović, V. N., Daković, M., & Stanković, L. J. (2003). Performances of quadratic time-frequency distributions as instantaneous frequency estimators. IEEE Transactions on Signal Processing, 51(1), 77–89.
Daković, M., Ivanović, V. N., & Stanković, L. J. (2003). On the S-method based instantaneous frequency estimation. Proc. Int. Sym. on SP and its Applications, Paris, France.
Ivanović, V. N., & Jovanovski, S. (2008). A signal adaptive system for time-frequency analysis. Electronics Letters, 44(21), 1279–1280.
Stanković, L. J. (1996). Auto-terms representation by the reduced interference distributions; The procedure for a kernel design. IEEE Transactions on Signal Processing, 44(6), 1557–1564.
Stanković, L. J., & Böhme, J. F. (1999). Time-frequency analysis of multiple resonances in combustion engine signals. IEEE Transactions on Signal Processing, 42(1), 225–229.
Liu, K. J. R. (1993). Novel parallel architectures for short-time Fourier transform. IEEE Transactions on Circuits and Systems II, Express Briefs, 40(12), 786–789.
Maharatna, K., Dhar, A. S., & Banerjee, S. (2001). A VLSI array architecture for realization of DFT, DHT, DCT and DST. Signal Processing, 41(3), 1357–1377.
Jovanovski, S., Ivanović, V. N., & Radović, N. (2009). An efficient real-time method for time-varying filter region of support estimation. Proc. IEEE SPS DSP & SPE Workshops, Marco Island, USA, 513–517.
Ivanović, V.N., Stojanović, R., Stanković, LJ. (2006). Multiple clock cycle architecture for the VLSI design of a system for time-frequency analysis. EURASIP J Appl.SP, Spec. Issue Design Methods for DSP Syst., 1–18.
Jovanovski, S., Ivanovic, V.N. (2009). An efficient hardware design of an optimal nonstationary filtering system. Proc. IEEE ICASSP, Taipei, Taiwan, in print.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Jovanovski, S., Ivanović, V.(. Signal Adaptive Pipelined Hardware Design of Time-Varying Optimal Filter for Highly Nonstationary FM Signal Estimation. J Sign Process Syst 62, 287–300 (2011). https://doi.org/10.1007/s11265-010-0462-0
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11265-010-0462-0