Efficient Alias-free Level Crossing Sampling
Authors: Negar Riazifar, Nigel G. Stocks
This paper proposes strategies in level crossing (LC) sampling and reconstruction that provide alias-free high-fidelity signal reconstruction for speech signals without exponentially increasing sample number with increasing bit-depth. We introduce methods in LC sampling that reduce the sampling rate close to the Nyquist frequency even for large bit-depth. The results indicate that larger variation in the sampling intervals leads to alias-free sampling scheme; this is achieved by either reducing the bit-depth or adding a jitter to the system for high bit-depths. In conjunction with windowing, the signal is reconstructed from the LC samples using an efficient Toeplitz reconstruction algorithm.
Keywords: Alias-free, level crossing sampling, spectrum, trigonometric polynomial.Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 173
 E. Allier, G. Sicard, L. Fesquet and M. Renaudin, “Asynchronous level crossing analog to digital converters,” Meas. J. Int. Meas. Confed., vol. 37, pp. 296–309, 2005.
 N. Sayiner, H. V. Sorensen and T. R. Viswanathan, “A level-crossing sampling scheme for A/D conversion,” IEEE Transaction on Circuits and Systems-11: Analog and Digital Signal Processing, vol. 43, pp. 335-339, 1996.
 D. Rzepka, M. Mi´skowicz, D. Koscielnik and N. T. Thao, “Reconstruction of signals from level-crossing samples using implicit information,” IEEE Access, vol. 6, pp. 35001–35011, 2018.
 D. Hand and M. S. W. Chen, “A non-uniform sampling ADC architecture with embedded alias-free asynchronous filter,” GLOBECOM - Signal Process. Commun. Symp., pp. 3707–3712, 2012.
 B. Schell and Y. Tsividis, “A continuous-time ADC/DSP/DAC system with no clock and with activity-dependent power dissipation,” IEEE J. Solid-State Circuits, vol. 43, pp. 2472–2481, 2008.
 T. F. Wu, S. Dey and M. S. W. Chen, “A nonuniform sampling ADC architecture with reconfigurable digital anti-aliasing filter,” IEEE Trans. Circuits Syst. I Regul. Pap., vol. 63, pp. 1639–1651, 2016.
 S. Patil, A. Ratiu, D. Morche and Y. Tsividis, “A 3–10 fJ/conv-step error-shaping alias-free continuous-time ADC,” IEEE Journal of Solid-State Circuits, vol. 51, pp. 908–918, 2016.
 M. Kurchuk, C. W. Wu, D. Morche and Y. Tsividis, “Event-driven GHz-range continuous-time digital signal processor with activity-dependent power dissipation,” IEEE Journal of Solid-State Circuits, vol. 47, pp. 2164-2173, 2012.
 C. Luo, “Non-uniform sampling: algorithms and architectures,” PhD Thesis, Georgia Institute of Technology, 2012.
 Y. Tsividis, “Digital signal processing in continuous time: A possibility for avoiding aliasing and reducing quantization error ,” IEEE International Conference on Acoustics, Speech, and Signal Processing, vol. 2, pp. 589-592, 2004.
 T. F. Wu, C. R. Ho and M. S. W. Chen, “A flash-based non-uniform sampling ADC with hybrid quantization enabling digital anti-aliasing filter,” IEEE J. Solid-State Circuits, vol. 52, pp. 2335–2349, 2017.
 C. Wijenayake, J. Scutts and A. Ignjatovi´c, “Signal recovery algorithm for 2-level amplitude sampling using chromatic signal approximations,” Signal Processing, vol. 153, pp. 143–152, 2018.
 H. G. Feichtinger, K. Grochenig and T. Strohmer, “Efficent numerical methods in non-uniform sampling theory,” Numer. Math., vol. 69, pp. 423-440, 1995.
 K. Grochenig, “Irregular sampling, Toeplitz matrices, and the approximation of entire functions of exponential type,” Math. Comput., vol. 68, pp. 749-765, 2002.
 K. Kozmin, J. Johansson and J. Delsing, “Level-crossing ADC performance evaluation toward ultrasound application,” IEEE Trans. Circuits Syst. I Regul. Pap., vol. 56, pp. 1708–1719, 2009.
 M. B. Mashhadi, N. Salarieh, E. S. Farahani and F. Marvasti, “Level crossing speech sampling and its sparsity promoting reconstruction using an iterative method with adaptive thresholding,” IET Signal Process., vol. 11, pp. 721–726, 2017.
 J. S. Garofolo, L. F. Lamel, W. M. Fisher, J. G. Fiscus, D. S. Pallett, N. L. Dahlgren and V. Zue, “TIMIT acoustic-phonetic continuous speech corpus,” 1993. URL: https://catalog.ldc.upenn.edu/LDC93S1.
 N. Riazifar and N. G. Stocks, “Efficient high fidelity signal reconstruction based on level crossing sampling,” World Academy of Science, Engineering and Technology, vol. 5, pp. 487-496, 2021.
 I. Bilinskis, E. Boole and K. Sudars, “Combination of periodic and alias-free non-uniform signal sampling for wideband signal digitizing and compressed transmitting based on picosecond-resolution event timing,” Signal Processing Symposium, 2017.