List of Articles modulator

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  1 - Analysis of an Electro-Optic Modulator Based Photonic Crystal Nanobeam Cavity Coupled to Alternating Structure of Graphene on Aluminum Oxide
  Mozafaredin FerdosianTehrani Rahim Ghayour Maryam Mohitpour
  10.30495/jce.2022.691828
  In this paper, we present an electro-optical modulator based on graphene absorption. In this structure, graphene is placed on aluminum oxide, the structure of which is repeated alternately. This alternating structure of graphene on aluminum oxide is located inside a sem More

  In this paper, we present an electro-optical modulator based on graphene absorption. In this structure, graphene is placed on aluminum oxide, the structure of which is repeated alternately. This alternating structure of graphene on aluminum oxide is located inside a semi-cylindrical cavity in a 1-dimensional photonic crystal nanobeam cavity. Unlike previous articles, which consisted of cylinder holes and different areas in the nanobeam cavity is formed by changing the radius of the holes, in this structure, semi-cylinder holes have been used and, different areas are formed by rotating these semi-cylinders. This type of crystal photonics has a high quality factor. Also, this type of modulator requires little space after construction, so they are a very good option for integrated circuits. In this paper, three-dimensional finite-difference time-domain method is used for analysis. In this modulator, it is observed that by changing the bias voltage, the amount of absorption peak and also its resonance wavelength are changed. As a result of these changes, we achieve a modulation depth of about 7dB. Our proposed structure can have potential applications in integrated optical circuits, especially in telecommunication frequencies. Manuscript profile
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  2 - Design and Simulation of Fourth Order Sigma-Delta Modulator using Parametric Amplifier with Dynamic Threshold for Digital Hearing Aid Application
  Shima Alizadeh Zanjani Abumoslem Jannesari Pooya Torkzadeh
  10.30495/jce.2023.1983365.1198
  In this paper, a fourth-order, OTA-free, single-bit, low-consumption discrete-time (DT) delta-sigma (ΔΣ) modulator with CIFF structure is proposed for hearing aid applications. In portable medical devices such as hearing aids that are used permanently, the b More

  In this paper, a fourth-order, OTA-free, single-bit, low-consumption discrete-time (DT) delta-sigma (ΔΣ) modulator with CIFF structure is proposed for hearing aid applications. In portable medical devices such as hearing aids that are used permanently, the battery life and energy dissipation are very important. In a typical delta sigma modulator, the power-hungry parts are the OTA. Therefore, the elimination of OTAs is a challenge, and the proposed modulator uses new differential parametric amplifiers, with dynamic thresholde in even stages and inverter-based amplifiers in odd delta sigma stages instead of the OTAs. The dynamic threshold PMOS technique has been used for the first time in differential MPA, and the theoretical analyzes and simulations performed show better performance than the traditional method. Also, a chopper circuit is used on the first fstage to reduce the harmonics and flicker noise. The proposed differential modulator is simulated using standard 180 nm CMOS technology, which achieves 90.5 dB SFDR and 64 dB SNDR with an input bandwidth frequency of 10 kHz and an oversampling ratio of 128. The power supply is 1V and the FOMW were obtained as 3.43 PJ/step. Manuscript profile
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  3 - A Single loop Feed Forward Sigma-Delta Modulator for GSM Standard
  Mohsen Beiranvand Ebrahim Rahimi Gholamreza Babaabasi
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  4 - Design of a Digital Sigma Delta Modulator with Separate Pipeline Lines for Fractional Frequency Synthesizers
  Leila Jahan panah Seyed Ali Sadatnoori Iman Chaharmahali
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  5 - Single Pixel Imaging using Compressive Sensing and Spatial Light Modulator
  Mohammad Roueinfar Mahdi Salmanian Ali Aghakasiri Abbas Bashiri Saeed Babanezhad
  Conventional cameras based on an array of pixels (CCD or CMOS) are commonly used to capture a target image at a certain distance. In this type of camera, all pixels are used to create the image. For CCD-based cameras at other wavelengths, including infrared and terahert More

  Conventional cameras based on an array of pixels (CCD or CMOS) are commonly used to capture a target image at a certain distance. In this type of camera, all pixels are used to create the image. For CCD-based cameras at other wavelengths, including infrared and terahertz, having all the pixels increases the cost of the camera. The aim of this study is to design and build an imaging setup using a single pixel method to reduce the cost of the camera and to reconstruct the target image using less data. We verify this method for visible band due to availability of visible light equipment that can be generalized this method to other wavelengths. We use a spatial light modulator (SLM) produces two-level optical masks with random distribution with 20 x 20 pixels and a size of 10 x 10 cm and illuminates the target at a repetition rate of 1 Hz. The reflection of each mask from the target captured by a CCD camera and then we average of all pixels of the CCD to equate it with a single-pixel detector. The target image is reconstructed using a compressive sensing algorithm. The process of reconstructing the target image is performed using a minimum number of masks. We use the two norms L1 and TV to retrieve the target image. The simulation results show norm TV is more successful in target image retrieval. Also, with increasing the number of masks, the success rate in retrieving the target image increases. Manuscript profile
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  6 - An all optical photonic crystal based FSK demodulator suitable for optical communications
  akram asghari govar
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  7 - Designing and Optimization of Plasmonic Modulator Structure Based on the Active Materials of ITO and Graphene
  Abbas Eslami Mojtaba Sadeghi Zahra Adelpour
  In the last decade, optical integrated circuits, including modulators, have made significant progress in optical communications, imaging, and sensors. Among the active materials used in modulators, graphene and indium tin oxide (ITO) are some of the suitable options amo More

  In the last decade, optical integrated circuits, including modulators, have made significant progress in optical communications, imaging, and sensors. Among the active materials used in modulators, graphene and indium tin oxide (ITO) are some of the suitable options among the active materials for modulation action due to their epsilon-near-zero (ENZ) characteristics, speed, and considerable response. In this paper, by applying direct coupling of light, the structure of plasmonic modulator in three-dimensional mode has been designed. And by changing the thickness of ITO, HfO2 (hafnium oxide) layers and waveguide width, the structure is optimized. Optimization thickness of 3 nm for ITO, 5nm for HfO2 and 280nm for waveguide width is achieved. The results of three-dimensional simulations of this paper with appropriate coupling show that the insertion loss (IL) of three-dimensional mode have not changed and the extinction ratio (ER) of the modulator has been slightly reduced in comparison with two-dimensional mode .On the other hand, appropriate and optimal coupling has no effect on energy consumption.Three-dimensional results show that the proposed plasmonic modulator can achieve an extinction ratio of 13.9 dB, an insertion loss of 2.9 dB, modulation speed of 140.9 GHz and a very low power consumption of 1.51 fj/bit for a 1µm length of the modulator, at 0.5 V voltage and a wavelength of 1.55 µm. Our design demonstrates a considerable reduction in energy consumption and improvement in extinction ratio compared to previous works. Also, for a 2 µm length of the modulator, an extinction ratio of 27.76 dB, an insertion loss of 5.68 dB, modulation speed of 70.14 GHz and power consumption of 2.88 fj/bit is achieved. Manuscript profile
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  8 - Design and Simulation of Ultra-Low-Power Sigma-Delta Converter Using the Fully Differential Inverter-Based Amplifier for Digital Hearing Aids Application
  Shima Alizadeh Zanjani Abumoslem Jannesari Pooya Torkzadeh
  In this paper, an ultra-low-power, second-order, discrete-time sigma-delta converter is proposed for hearing aids application. In portable biomedical devices such as hearing aids that permanently use, the battery lifetime and power dissipation are very considerable. In More

  In this paper, an ultra-low-power, second-order, discrete-time sigma-delta converter is proposed for hearing aids application. In portable biomedical devices such as hearing aids that permanently use, the battery lifetime and power dissipation are very considerable. In a typical delta-sigma modulator, the OTAs are the most power-consuming parts. The OTAs elimination in the converters is now challenging. Therefore the converter with a self-biased fully differential inverter-based amplifier was designed with only 1.15 µw static power dissipation at a 1-volt power supply. The inverter-based amplifier was used instead of the OTAs in two stages of the modulator. The modulator’s structure is CIFB, single-loop, and single bit. The proposed differential modulator was designed and simulated using a standard 180 nm CMOS technology, which obtained SFDR and SNDR of 95.2878 dB and 64.004 dB, respectively. The sampling frequency is considered 2.56 MHz, and the input signal bandwidth is 10kHz. The modulator consumes power just about 5.1091 µW, and the FOMW achieves 0.197 pj/step. Manuscript profile
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  9 - Design of Novel Low-Power Single-Loop Sigma-Delta Modulator by Reduction of Amplifiers in the Loop-Filter for Speech Recognition Applications
  Sahar Doolabi Mehdi Taghizadeh Mohammad Hossein Fatehi Jasem Jamali
  In this paper, a novel general architecture for single-loop Sigma-Delta Modulator is presented by combination low-distortion and noise-coupled techniques for high-resolution low-power applications. The low-distortion technique in the proposed architecture makes its sign More

  In this paper, a novel general architecture for single-loop Sigma-Delta Modulator is presented by combination low-distortion and noise-coupled techniques for high-resolution low-power applications. The low-distortion technique in the proposed architecture makes its signal transfer function equal to one. In addition, the noise-coupled technique increases the order of quantization noise shaping at the modulator output. The purpose of using these techniques in design of the architecture is to increase the order of the modulator without needing to additional operational amplifiers during its circuit implementation to finally achieve a low-power modulator compared to similar ones. To reduce the required amplifiers, a second order infinite impulse response (IIR) filter was used instead of an integrator in the modulator loop. To evaluate the performance of the proposed structure, its implementation and simulation for speech recognition application, i.e., digital hearing aids, were performed in 180nm CMOS (complementary metal-oxide semiconductor) technology. For a third-order structure with a sampling rate of 64 and an input sine signal of -6dBFS and a sampling frequency of 2.56MHz, the signal to noise and distortion (SNDR) is 81.9dB and the dynamic range (DR) is 88dB. The power consumption of the modulator is 126.9 μW and its bandwidth is 20 KHz. The results of circuit and system level simulations prove its performance. Manuscript profile
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  10 - A Smart Noise-Coupling Technique for low power DT-Σ∆ Modulators
  Habibeh Fakhraie Tohid Moosazadeh Reza Sabbaghi-nadooshan Alireza Hassanzadeh
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  11 - Immunomodulatory Effect of Propolis on IFN-γ, IL-17A and IL-23 Production in Human Peripheral Blood Mononuclear Cells Treated with Pseudomonas aeruginosa Ag
  Farah Alaa Alwaeely Mohammad Abd kadhum Alsaadi Kaiser N. Madlum
  10.22034/jchr.2021.685425
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