The Experts below are selected from a list of 1083 Experts worldwide ranked by ideXlab platform

Victor Lubecke - One of the best experts on this subject based on the ideXlab platform.

  • feasibility of heart rate variability measurement from quadrature doppler radar using Arctangent demodulation with dc offset compensation
    International Conference of the IEEE Engineering in Medicine and Biology Society, 2007
    Co-Authors: W Massagram, Victor Lubecke, Noah Hafner, Byungkwan Park, Anders Hostmadsen, Olga Boriclubecke
    Abstract:

    This paper describes the experimental results of the beat-to-beat interval measurement from a quadrature Doppler radar system utilizing Arctangent demodulation with DC offset compensation techniques. The comparison in SDNN and in RMSDD of both signals demonstrates the potential of using quadrature Doppler radar for HRV analysis.

  • Arctangent demodulation with dc offset compensation in quadrature doppler radar receiver systems
    IEEE Transactions on Microwave Theory and Techniques, 2007
    Co-Authors: Byungkwon Park, Olga Boriclubecke, Victor Lubecke
    Abstract:

    Direct-conversion microwave Doppler radar can be used to detect cardiopulmonary activity at a distance. One challenge for such detection in single channel receivers is demodulation sensitivity to target position, which can be overcome by using a quadrature receiver. This paper presents a mathematical analysis and experimental results demonstrating the effectiveness of Arctangent demodulation in quadrature receivers. A particular challenge in this technique is the presence of dc offset resulting from receiver imperfections and clutter reflections, in addition to dc information related to target position and associated phase. These dc components can be large compared to the ac motion-related signal, and thus, cannot simply be included in digitization without adversely affecting resolution. Presented here is a method for calibrating the dc offset while preserving the dc information and capturing the motion-related signal with maximum resolution. Experimental results demonstrate that Arctangent demodulation with dc offset compensation results in a significant improvement in heart rate measurement accuracy over quadrature channel selection, with a standard deviation of less than 1 beat/min

R Punchalard - One of the best experts on this subject based on the ideXlab platform.

  • Arctangent gradient based adaptive algorithm for a second order adaptive iir notch filter
    Applied Mechanics and Materials, 2015
    Co-Authors: R Punchalard
    Abstract:

    Frequency estimation based on adaptive notch filter is very attractive due to simplicity and economy. This paper presents an Arctangent gradient (AG) based adaptive algorithm for a second-order constrained adaptive IIR notch filter (ANF). The motivation is to use an Arctangent value of the gradient signal to adjust the filter parameter. It is revealed that for slow adaptation, the AG can be considered as an unbiased estimator. The quantitative simulations have been conducted to support the superior of the proposed AG algorithm.

  • Arctangent based adaptive algorithm for a complex iir notch filter for frequency estimation and tracking
    Signal Processing, 2014
    Co-Authors: R Punchalard
    Abstract:

    An Arctangent (AT) based adaptive algorithm for a first-order complex adaptive IIR notch filter (CANF) is proposed in this paper. The objective of this work is to overcome some drawbacks including slow convergence speed and high sensitivity to impulsive noise of the previous gradient and nongradient based adaptive algorithms. The proposed AT algorithm employs the ratio of output to regressor signal as an error criterion where the Arctangent value of such a ratio is employed to adjust the filter parameter. It is found that the proposed algorithm provides not only high speed convergence but also high impulsive noise robustness. Moreover, very low bias of the frequency estimate is also obtained. In addition, difference equation for the convergence in the mean and coarse stability bound in mean sense are derived. Computer simulations are conducted to show the performance of the proposed AT algorithm.

Olga Boriclubecke - One of the best experts on this subject based on the ideXlab platform.

  • feasibility of heart rate variability measurement from quadrature doppler radar using Arctangent demodulation with dc offset compensation
    International Conference of the IEEE Engineering in Medicine and Biology Society, 2007
    Co-Authors: W Massagram, Victor Lubecke, Noah Hafner, Byungkwan Park, Anders Hostmadsen, Olga Boriclubecke
    Abstract:

    This paper describes the experimental results of the beat-to-beat interval measurement from a quadrature Doppler radar system utilizing Arctangent demodulation with DC offset compensation techniques. The comparison in SDNN and in RMSDD of both signals demonstrates the potential of using quadrature Doppler radar for HRV analysis.

  • Arctangent demodulation with dc offset compensation in quadrature doppler radar receiver systems
    IEEE Transactions on Microwave Theory and Techniques, 2007
    Co-Authors: Byungkwon Park, Olga Boriclubecke, Victor Lubecke
    Abstract:

    Direct-conversion microwave Doppler radar can be used to detect cardiopulmonary activity at a distance. One challenge for such detection in single channel receivers is demodulation sensitivity to target position, which can be overcome by using a quadrature receiver. This paper presents a mathematical analysis and experimental results demonstrating the effectiveness of Arctangent demodulation in quadrature receivers. A particular challenge in this technique is the presence of dc offset resulting from receiver imperfections and clutter reflections, in addition to dc information related to target position and associated phase. These dc components can be large compared to the ac motion-related signal, and thus, cannot simply be included in digitization without adversely affecting resolution. Presented here is a method for calibrating the dc offset while preserving the dc information and capturing the motion-related signal with maximum resolution. Experimental results demonstrate that Arctangent demodulation with dc offset compensation results in a significant improvement in heart rate measurement accuracy over quadrature channel selection, with a standard deviation of less than 1 beat/min

Sinchong Park - One of the best experts on this subject based on the ideXlab platform.

  • Arctangent processor design for the frequency offset estimation of ieee 802 16d wirelessman ofdm system
    Signal Processing Systems, 2007
    Co-Authors: Taekyu Kim, Sinchong Park
    Abstract:

    This paper presents a hardware design of an Arctangent processor for the IEEE 802.16d WirelessMAN-OFDM system. The Arctangent processor is required in most OFDM-based communication system to estimate the frequency offset. We proposed an Arctangent processor which can perform Arctangent evaluation with efficiency of hardware size considering the operating speed. The proposed Arctangent processor does not require the division value of imaginary/real for the input argument, and uses these two values, respectively, to look up the tangent ROM table which has only the Arctangent values for octant phase, i.e. zero to ?/4 rad. The contribution of this design is the suggestion about the trade-off between the accuracy and complexity for Arctangent evaluation considering the requirement allowed in WirelessMAN-OFDM standard. Consequently, the designed Arctangent process for WirelessMAN-OFDM system takes six clocks to evaluate an Arctangent value and has the resolution of 2?/256 rad. The maximum absolute error of this Arctangent hardware is 1.225e-2 rad (0.7°) comparing to mathematical result.

  • Arctangent processor design for the frequency offset estimation of ieee 802 16d wirelessman ofdm system
    ITC-CSCC :International Technical Conference on Circuits Systems Computers and Communications, 2007
    Co-Authors: Taekyu Kim, Sinchong Park
    Abstract:

    This paper presents a hardware design of an Arctangent processor for the IEEE 802.16d WirelessMANOFDM system. The proposed Arctangent processor does not require the division value of imaginary/real for the input argument, and uses these two values, respectively, to look up the tangent ROM table. We reduce the tangent look-up table size to one eighth of 2π rad using the imaginary and real component exchange method for memory size and operation speed. Consequently, the designed Arctangent process for WirelessMAN-OFDM system takes six clocks to evaluate an Arctangent value and has the resolution of 2π/256 rad. The maximum absolute error of this Arctangent hardware is 1.225e-2 rad (0.7°) comparing to mathematical result.

Byungkwon Park - One of the best experts on this subject based on the ideXlab platform.

  • Arctangent demodulation with dc offset compensation in quadrature doppler radar receiver systems
    IEEE Transactions on Microwave Theory and Techniques, 2007
    Co-Authors: Byungkwon Park, Olga Boriclubecke, Victor Lubecke
    Abstract:

    Direct-conversion microwave Doppler radar can be used to detect cardiopulmonary activity at a distance. One challenge for such detection in single channel receivers is demodulation sensitivity to target position, which can be overcome by using a quadrature receiver. This paper presents a mathematical analysis and experimental results demonstrating the effectiveness of Arctangent demodulation in quadrature receivers. A particular challenge in this technique is the presence of dc offset resulting from receiver imperfections and clutter reflections, in addition to dc information related to target position and associated phase. These dc components can be large compared to the ac motion-related signal, and thus, cannot simply be included in digitization without adversely affecting resolution. Presented here is a method for calibrating the dc offset while preserving the dc information and capturing the motion-related signal with maximum resolution. Experimental results demonstrate that Arctangent demodulation with dc offset compensation results in a significant improvement in heart rate measurement accuracy over quadrature channel selection, with a standard deviation of less than 1 beat/min