The Experts below are selected from a list of 201486 Experts worldwide ranked by ideXlab platform

Kun Qiu - One of the best experts on this subject based on the ideXlab platform.

  • analogue to digital converter phase insensitive dispersion search method with large search step size for low computational cost
    Iet Communications, 2016
    Co-Authors: Yun Ling, Kun Qiu
    Abstract:

    Accumulated chromatic dispersion (CD) estimation is crucial for frequency-domain equalisation in an optical coherent digital receiver. To solve the problems of small search step size and analogue-to-digital converter (ADC) sampling phase sensitivity from conventional CD searching algorithm, a CD searching method with modified shift parameters and waveforms is proposed in this study. The modified CD searching method allows a much larger search step size and can achieve faster CD estimation with low computational complexity. The performance of the modified CD searching method is also insensitive to ADC sampling phase. On the basis of simulation results, a very low search error probability is confirmed with a search step size of 50 km. About 1 K symbols are found to be enough for dispersion estimation. After the frequency-domain equaliser (FDE) with the estimated dispersion value, the residual dispersion length <30 km can be well compensated with a 9-tap adaptive time-domain equaliser (TDE) with fast convergence. The overall error rate performance of the tunable electrical dispersion compensation is also studied and compared with lumped and distributed optical dispersion compensation for dynamically switched optical networks.

  • analogue-to-digital converter phase insensitive dispersion search method with large search step size for low computational cost
    IET Communications, 2016
    Co-Authors: Yun Ling, Kun Qiu
    Abstract:

    Accumulated chromatic dispersion (CD) estimation is crucial for frequency-domain equalisation in an optical coherent digital receiver. To solve the problems of small search step size and analogue-to-digital converter (ADC) sampling phase sensitivity from conventional CD searching algorithm, a CD searching method with modified shift parameters and waveforms is proposed in this study. The modified CD searching method allows a much larger search step size and can achieve faster CD estimation with low computational complexity. The performance of the modified CD searching method is also insensitive to ADC sampling phase. On the basis of simulation results, a very low search error probability is confirmed with a search step size of 50 km. About 1 K symbols are found to be enough for dispersion estimation. After the frequency-domain equaliser (FDE) with the estimated dispersion value, the residual dispersion length

Adolfo V. T. Cartaxo - One of the best experts on this subject based on the ideXlab platform.

  • SNR approach for performance evaluation of time-stretching photonic analogue to digital converter system.
    Optics express, 2011
    Co-Authors: Tiago M. F. Alves, Adolfo V. T. Cartaxo
    Abstract:

    A semi-analytical simulation method (SASM) is proposed to evaluate the signal-to-noise ratio (SNR) of time stretched signals at the output of photonic analogue-to-digital converter (Ph-ADC) system. Analytical expressions of the signal at Ph-ADC output considering generic electrical signals applied to the electro-optic modulators of the Ph-ADC are derived. The contribution to the total variance of the received signal from the noise introduced by the electrical transmitter and receiver, and by the optical amplifier are derived analytically taking into account the pulsed nature of the optical signal. The proposed SASM shows excellent agreement of SNR estimates with the estimates provided by Monte Carlo simulation. This result is confirmed for variance dominantly imposed by the noise introduced by the electrical transmitter, by the optical amplifier and by the electrical receiver. A simplified approach is also proposed and compared with previous work. It is shown that mean power estimates obtained from this simplified approach are valid while the modulator is operating in the linear region and the signal is not affected by the frequency response of the electrical receiver filter. Additionally, it is concluded that the estimates of the noise variance due to the electrical transmitter are acceptable when a small signal analysis of noise along the Ph-ADC is valid.

Minjae Lee - One of the best experts on this subject based on the ideXlab platform.

  • Scaled-down reference switching scheme for low-power SAR ADCs
    Analog Integrated Circuits and Signal Processing, 2018
    Co-Authors: Seung-uk Baek, Kang-yoon Lee, Se-won Lee, Minjae Lee
    Abstract:

    An energy-efficient scaled-down reference (SDR) digital-to-analogue converter switching sequence is presented for a low-power successive approximation register analogue-to-digital converter. Owing to the fact that the proposed technique utilizes only a quarter of the capacitor array for input sampling, an SDR (V_ref/4) and ground (Gnd) for the same input are required for conversion cycles, which achieve reduced switching energy and high linearity. The SDR switching structure improves the efficiency of average switching energy by 99.61% and reduces the total number of required capacitors in the digital-to-analogue converter arrays by 50% compared to the conventional structure.

  • Energy-efficient switching scheme for SAR ADC using zero-energy dual capacitor switching
    Analog Integrated Circuits and Signal Processing, 2018
    Co-Authors: Seung-uk Baek, Kang-yoon Lee, Minjae Lee
    Abstract:

    An energy-efficient capacitor switching scheme is presented for a successive approximation register analogue-to-digital converter. The new switching method removes the switching energy loss in the first three comparison cycles and significantly reduces the power consumption in the fourth bit cycle, by combining the negative switching and the energy-efficient up-transition. In addition, a low-power monotonic procedure is implemented for the rest of bit-cycles. The proposed switching technique improves the average switching energy efficiency by 99.31% and reduces the total capacitance size by 75% compared with a conventional binary-search algorithm.

Daniel Rönnow - One of the best experts on this subject based on the ideXlab platform.

Yun Ling - One of the best experts on this subject based on the ideXlab platform.

  • analogue to digital converter phase insensitive dispersion search method with large search step size for low computational cost
    Iet Communications, 2016
    Co-Authors: Yun Ling, Kun Qiu
    Abstract:

    Accumulated chromatic dispersion (CD) estimation is crucial for frequency-domain equalisation in an optical coherent digital receiver. To solve the problems of small search step size and analogue-to-digital converter (ADC) sampling phase sensitivity from conventional CD searching algorithm, a CD searching method with modified shift parameters and waveforms is proposed in this study. The modified CD searching method allows a much larger search step size and can achieve faster CD estimation with low computational complexity. The performance of the modified CD searching method is also insensitive to ADC sampling phase. On the basis of simulation results, a very low search error probability is confirmed with a search step size of 50 km. About 1 K symbols are found to be enough for dispersion estimation. After the frequency-domain equaliser (FDE) with the estimated dispersion value, the residual dispersion length <30 km can be well compensated with a 9-tap adaptive time-domain equaliser (TDE) with fast convergence. The overall error rate performance of the tunable electrical dispersion compensation is also studied and compared with lumped and distributed optical dispersion compensation for dynamically switched optical networks.

  • analogue-to-digital converter phase insensitive dispersion search method with large search step size for low computational cost
    IET Communications, 2016
    Co-Authors: Yun Ling, Kun Qiu
    Abstract:

    Accumulated chromatic dispersion (CD) estimation is crucial for frequency-domain equalisation in an optical coherent digital receiver. To solve the problems of small search step size and analogue-to-digital converter (ADC) sampling phase sensitivity from conventional CD searching algorithm, a CD searching method with modified shift parameters and waveforms is proposed in this study. The modified CD searching method allows a much larger search step size and can achieve faster CD estimation with low computational complexity. The performance of the modified CD searching method is also insensitive to ADC sampling phase. On the basis of simulation results, a very low search error probability is confirmed with a search step size of 50 km. About 1 K symbols are found to be enough for dispersion estimation. After the frequency-domain equaliser (FDE) with the estimated dispersion value, the residual dispersion length