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Amit Mehrotra - One of the best experts on this subject based on the ideXlab platform.

  • noise analysis of phase locked loops
    IEEE Transactions on Circuits and Systems I-regular Papers, 2002
    Co-Authors: Amit Mehrotra
    Abstract:

    This work addresses the problem of noise analysis of phase-locked loops (PLLs). The problem is formulated as a stochastic differential equation and is solved in the presence of circuit white noise sources yielding the spectrum of the PLL output. Specifically, the effect of loop Filter characteristics, phase-frequency detector, and phase noise of the open-loop voltage-controlled oscillator (VCO) on the PLL output spectrum is quantified. These results are derived using a full nonlinear analysis of the VCO in the feedback loop and cannot be predicted using traditional linear analyses or the phase noise analysis of open-loop oscillators. The computed spectrum matches well with measured results; specifically, the shape of the output spectrum matches very well with measured PLL output spectra reported in the literature for different kinds of loop Filters and phase detectors. The PLL output spectrum computation only requires the phase noise of the VCO, loop Filter and phase detector noise, phase detector gain, and loop Filter Transfer Function and does not require the transient simulation of the entire PLL which can be very expensive. The noise analysis technique is illustrated with some examples.

  • noise analysis of phase locked loops
    International Conference on Computer Aided Design, 2000
    Co-Authors: Amit Mehrotra
    Abstract:

    This work addresses the problem of noise analysis of phase locked loops (PLLs). The problem is formulated as a stochastic differential equation and is solved in presence of circuit white noise sources yielding the spectrum of the PLL output. Specifically, the effect of loop Filter characteristics, phase-frequency detector and phase noise of the open loop voltage controlled oscillator (VCO) on the PLL output spectrum is quantified. These results are derived using a full nonlinear analysis of the VCO in the feedback loop and cannot be predicted using traditional linear analyses or the phase noise analysis of open loop oscillators. The computed spectrum matches well with measured results, specifically, the shape of the output spectrum matches very well with measured PLL output spectra reported in the literature for different kinds of loop Filters and phase detectors. The PLL output spectrum computation only requires the phase noise of the VCO, loop Filter and phase detector noise, phase detector gain and loop Filter Transfer Function and does not require the transient simulation of the entire PLL which can be very expensive. The noise analysis technique is illustrated with some examples.

Chunming Chang - One of the best experts on this subject based on the ideXlab platform.

  • analytical synthesis of voltage mode even odd nth order differential difference current conveyor and fully differential current conveyor ii grounded resistor and capacitor universal Filter structures
    International Journal of Circuit Theory and Applications, 2015
    Co-Authors: Chunming Chang, M N S Swamy, Ahmed M Soliman
    Abstract:

    Summary A complete definition of an odd/even-nth-order notch or band-reject Filter Transfer Function is presented. Based on the differences between the input voltage and (i) an nth-order high-pass; (ii) a traditional nth-order notch; and (iii) an nth-order all-pass Filtering Transfer Function, a systematic method has been proposed to derive a universal Filter structure that can realize voltage-mode odd/even-nth-order low-pass, band-pass, high-pass, all-pass and traditional notch Filters. The intrinsic capability of voltage-mode addition and subtraction of the two active elements, differential difference current conveyors and fully differential current conveyors, is used to advantage in the aforementioned synthesis procedure. Based upon the definition of an nth-order notch or band-reject Filter Transfer Function proposed in this paper, the aforementioned universal one has been further extended to the newly defined nth-order band rejection Filter. The voltage and current tracking errors of the two active elements are compensated by varying the resistances of the proposed Filter. Filtering feasibility, stability, component sensitivities, linear and dynamic ranges, power consumption, and noise are simulated using H-Spice with 0.35 µm process. Compared to some of the recently reported universal biquads, the new one is shown to enjoy the lowest component sensitivities and the best output accuracy for all-pass signals. Moreover, Monte Carlo and two-tone tests for intermodulation linearity simulations are also investigated. Copyright © 2014 John Wiley & Sons, Ltd.

  • analytical synthesis of high order single ended input ota grounded c all pass and band reject Filter structures
    IEEE Transactions on Circuits and Systems, 2006
    Co-Authors: Chunming Chang, Chunli Hou, Wenyaw Chung, Jiunwei Horng
    Abstract:

    The synthesis method based on the analytical solution of a single nth-order Filter Transfer Function and the generation of n+1 simple and realizable Transfer Functions implemented using lossless integrators and one additional constraint is applied to facilitate the development of new voltage-mode high-order operational transconductance amplifiers and capacitors (OTA-C) all-pass and band-reject Filters. The presented nth-order all-pass and band-reject Filters contain n+2, i.e., at least n fewer OTAs and enjoy lower component spread than the recently published Filter structures in addition to achieving three criteria: all single-ended-input OTAs, all grounded capacitors, and the least number of component counts, simultaneously. Furthermore, two different types of the synthesized Filter structures, equal capacitance and equal transconductance, are suggested for easier IC manufacture and simpler biasing architecture, respectively. H-Spice simulations, using 0.25-mum process and plusmn1.25-V supply voltages, validate theoretical predictions

  • analytical synthesis of voltage mode ota c all pass Filters for high frequency operation
    International Symposium on Circuits and Systems, 2003
    Co-Authors: Chunming Chang, Bashir M Alhashimi
    Abstract:

    This paper describes how analytical synthesis facilitates the development of new voltage mode Operational Transconductance Amplifiers and Capacitors or (OTA-C) all-pass Filters suitable for high-frequency operation. The proposed synthesis method is based on the analytical solution of a single, nth-order Filter Transfer Function and the generation of n realizable Transfer Functions implemented using lossless integrators and one additional constraint. The presented all-pass Filters contain the least number of passive and active elements for a given Filter order when compared with previous work. Furthermore, the method generates circuits that contain only grounded capacitors and single-input OTAs, attractive features for high-frequency applications.

You Min Chang - One of the best experts on this subject based on the ideXlab platform.

  • detailed theoretical and experimental study on single passband photonic microwave fir Filter using digital micromirror device and continuous wave supercontinuum
    Journal of Lightwave Technology, 2008
    Co-Authors: Ju Han Lee, You Min Chang
    Abstract:

    We perform a detailed theoretical and experimental study on the impact of the finesse (F) of a multiple wavelength channel optical Filter on output microwave Filter Transfer Function in a spectrum slicing-based photonic microwave finite-impulse response (FIR) Filter. For this paper, we use the combination of a digital micromirror device-based spatial light modulator and a continuous-wave, depolarized supercontinuum, since it allows us to perform flexible reconfiguration of output Filter Transfer Function. It is found that the superimposed broadband, low-pass RF Transfer Function induced by the wide linewidth single-wavelength channel effectively suppresses higher order, periodic resonance peaks as the F is reduced. The optical Filters with F=2 are found to provide the most effective suppression of higher order peaks, whatever the single channel waveform is: sinusoidal or Gaussian.

  • fully reconfigurable photonic microwave transversal Filter based on digital micromirror device and continuous wave incoherent supercontinuum source
    Applied Optics, 2007
    Co-Authors: Ju Han Lee, You Min Chang, Younggeun Han, Sang Bae Lee, Hae Yang Chung
    Abstract:

    The combined use of a programmable, digital micromirror device (DMD) and an ultrabroadband, cw, incoherent supercontinuum (SC) source is experimentally demonstrated to fully explore various aspects on the reconfiguration of a microwave Filter Transfer Function by creating a range of multiwavelength optical Filter shapes. Owing to both the unique characteristic of the DMD that an arbitrary optical Filter shape can be readily produced and the ultrabroad bandwidth of the cw SC source that is 3 times larger than that of Er-amplified spontaneous emission, a multiwavelength optical beam pattern can be generated with a large number of wavelength Filter taps apodized by an arbitrary amplitude window. Therefore various types of high-quality microwave Filter can be readily achieved through the spectrum slicing-based photonic microwave transversal Filter scheme. The experimental demonstration is performed in three aspects: the tuning of a Filter resonance bandwidth at a fixed resonance frequency, Filter resonance frequency tuning at a fixed resonance frequency, and flexible microwave Filter shape reconstruction.

Bruton Len - One of the best experts on this subject based on the ideXlab platform.

  • Hexagonal multi-beam analog RF aperture array
    'Institute of Electrical and Electronics Engineers (IEEE)', 2014
    Co-Authors: Wijenayake Chamith, Madanayake Arjuna, Bruton Len
    Abstract:

    A spatially discrete temporally continuous antenna array analog signal processing scheme that can produce highly selective hexagonal beams is proposed. A three dimensional (3-D) infinite impulse response (IIR) Filter Transfer Function having hexagonal beam shaped passabands in the 3-D space-time frequency domain ! is introduced. A hexagonal beam passband in ! produces a hexagonal radio beam in the array pattern, and having closely packed multiple hexagonal beams, one can optimally sense a given sky area in a typical radar/microwave imaging application. The proposed array processing scheme employs analog RF circuits for achieving scaling, summing and time delay as building blocks for the signal processing operation. The 3-D IIR Filter Transfer Function is derived by considering an example 10th-order 1-D Butterworth prototype polynomial

  • Hexagonal Multi-Beam Analog RF Aperture Array
    'Institute of Electrical and Electronics Engineers (IEEE)', 2014
    Co-Authors: Wijenayake Chamith, Madanayake Arjune, Bruton Len
    Abstract:

    A spatially discrete temporally continuous antenna array analog signal processing scheme that can produce highly selective hexagonal beams is proposed. A three dimensional (3-D) infinite impulse response (IIR) Filter Transfer Function having hexagonal beam shaped passabands in the 3-D space-time frequency domain omega is introduced. A hexagonal beam passband in w produces a hexagonal radio beam in the array pattern, and having closely packed multiple hexagonal beams, one can optimally sense a given sky area in a typical radar/microwave imaging application. The proposed array processing scheme employs analog RF circuits for achieving scaling, summing and time delay as building blocks for the signal processing operation. The 3-D IIR Filter Transfer Function is derived by considering an example 10th-order 1-D Butterworth prototype polynomial

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

  • detailed theoretical and experimental study on single passband photonic microwave fir Filter using digital micromirror device and continuous wave supercontinuum
    Journal of Lightwave Technology, 2008
    Co-Authors: Ju Han Lee, You Min Chang
    Abstract:

    We perform a detailed theoretical and experimental study on the impact of the finesse (F) of a multiple wavelength channel optical Filter on output microwave Filter Transfer Function in a spectrum slicing-based photonic microwave finite-impulse response (FIR) Filter. For this paper, we use the combination of a digital micromirror device-based spatial light modulator and a continuous-wave, depolarized supercontinuum, since it allows us to perform flexible reconfiguration of output Filter Transfer Function. It is found that the superimposed broadband, low-pass RF Transfer Function induced by the wide linewidth single-wavelength channel effectively suppresses higher order, periodic resonance peaks as the F is reduced. The optical Filters with F=2 are found to provide the most effective suppression of higher order peaks, whatever the single channel waveform is: sinusoidal or Gaussian.

  • fully reconfigurable photonic microwave transversal Filter based on digital micromirror device and continuous wave incoherent supercontinuum source
    Applied Optics, 2007
    Co-Authors: Ju Han Lee, You Min Chang, Younggeun Han, Sang Bae Lee, Hae Yang Chung
    Abstract:

    The combined use of a programmable, digital micromirror device (DMD) and an ultrabroadband, cw, incoherent supercontinuum (SC) source is experimentally demonstrated to fully explore various aspects on the reconfiguration of a microwave Filter Transfer Function by creating a range of multiwavelength optical Filter shapes. Owing to both the unique characteristic of the DMD that an arbitrary optical Filter shape can be readily produced and the ultrabroad bandwidth of the cw SC source that is 3 times larger than that of Er-amplified spontaneous emission, a multiwavelength optical beam pattern can be generated with a large number of wavelength Filter taps apodized by an arbitrary amplitude window. Therefore various types of high-quality microwave Filter can be readily achieved through the spectrum slicing-based photonic microwave transversal Filter scheme. The experimental demonstration is performed in three aspects: the tuning of a Filter resonance bandwidth at a fixed resonance frequency, Filter resonance frequency tuning at a fixed resonance frequency, and flexible microwave Filter shape reconstruction.