List of Articles wide band

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  1 - Design and Implementation of an Ultra-Wide Band, High Precision, and Low Noise Frequency Synthesizer
  Yas Hosseini Tehrani Nasser Masoumi
  10.7508/jist.2017.20.001
  This paper presents system-level design and implementation of an ultra-wide tunable, high precision, fast locking, low phase noise, and low power portable fractional-N frequency synthesizer. The output frequency of the proposed design is ranged from 54 MHz to 6.8GHz. Th More

  This paper presents system-level design and implementation of an ultra-wide tunable, high precision, fast locking, low phase noise, and low power portable fractional-N frequency synthesizer. The output frequency of the proposed design is ranged from 54 MHz to 6.8GHz. The VCO cores cover frequencies from 3.4GHz to 6.8GHz. The programmable output dividers allow generation of the lower frequencies. The frequency resolution of the implemented system is ±20 parts per million (ppm) over -40/85ºC. The output power is tunable between -4dBm and +5dBm. The implemented system has a phase adjust feature that allows shifting of the output phase in relation to the reference oscillator ranged from 0° to 180°. It can generate a wide range, high precision, and linear frequency sweep. The sweep rate, frequency step, and frequency range are tunable. The new frequency tuning algorithm, named Yas algorithm, is proposed to improve frequency precision of the synthesizer. To demonstrate the efficiency of the Yas algorithm, the simulation result MATLAB and the experimental measurements are presented. The system consumes 300mA; therefore, it can be powered by Li-Ion battery. The output phase noise is -95.55 dBc/Hz at 1KHz offset from 3GHz. The experimental measurement results demonstrate that the implemented frequency synthesizer can be used for applications, such as oscillator of spectrum analyzer, automatic test equipment, FMCW radars, high-performance clock source for high speed data converter Manuscript profile
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  2 - SVD-Based Adaptive Multiuser Detection for Optimized Chaotic DS-CDMA Systems
  S. Shaerbaf S. A. Seyedin
  In recent years, chaotic signals have created a new area in the designation of wideband communication systems. Most of the activity has focused on DS-CDMA systems, in which the conventional pseudo-noise sequences will be replaced by binary chaotic sequences. Unfortunat More

  In recent years, chaotic signals have created a new area in the designation of wideband communication systems. Most of the activity has focused on DS-CDMA systems, in which the conventional pseudo-noise sequences will be replaced by binary chaotic sequences. Unfortunately, despite the advantages of chaotic systems such as aperiodicity, low cost generation and noise-like spectrum, the performance of most of such designs is not still suitable for multiuser wireless channels. In this paper, we propose a novel method based on singular value decomposition for adaptive multiuser detection in chaos-based DS-CDMA systems. We also propose a new genetic algorithm-based method for the optimal generation of chaotic sequences in such systems. Simulation results show that our proposed nonlinear receiver with optimized chaotic sequences outperforms the conventional DS-CDMA systems with “maximal length” codes as well as non-optimized chaos-based DS-CDMA systems in all channel condition, particularly for under-loaded CDMA condition, which the number of active users is less than processing gain. Manuscript profile