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    Two channel abdominal PPG instrumentation

    , Article IFMBE Proceedings ; Volume 21 IFMBE, Issue 1 , 2008 , Pages 691-693 ; 16800737 (ISSN); 9783540691389 (ISBN) Gan, K. B ; Mohd Ali, M. A ; Zahedi, E ; Sharif University of Technology
    Springer Verlag  2008
    In this paper, a two channel abdominal PPG instrumentation is developed. The proposed instrument consists of IR-LED and its driver, photo-detector and data acquisition card. The modulation frequency generation, demodulation and digital signal processing is done completely in the digital domain using LabView. The results show that the developed instrument is able to acquire signal from the abdomen even at 4 cm source to detector separation. This instrument is intended for future application in trans-abdominal fetal heart rate detection. © 2008 Springer-Verlag  

    Novel coarse timing synchronization methods in OFDM systems using fourth-order statistics

    , Article IEEE Transactions on Vehicular Technology ; Volume 64, Issue 5 , 2015 , Pages 1904-1917 ; 00189545 (ISSN) Mohebbi, A ; Abdzadeh Ziabari, H ; Shayesteh, M. G ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    In this paper, the problem of coarse timing synchronization in orthogonal frequency-division multiplexing (OFDM) systems is investigated, and two new timing metrics with better performance are presented. The new metrics take advantage of two novel differential normalization functions that are based on the fourth-order statistics and are designed depending on the value of carrier frequency offset (CFO). The proposed timing metrics are theoretically evaluated using two different class separability criteria. It is shown that the new schemes considerably increase the difference between the correct and wrong timing points in comparison with previous methods. The computational complexity of the...