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Full-Text Articles in Electronic Devices and Semiconductor Manufacturing

Modeling Of Three-Phase Uniform Symmetrical Sampling Digital Pwm For Power Converter, Saad Mekhilef Sep 2006

Modeling Of Three-Phase Uniform Symmetrical Sampling Digital Pwm For Power Converter, Saad Mekhilef

Saad Mekhilef

A mathematical approach of modeling and analyzing three-phase pulsewidth modulation (PWM) is presented. The three-phase flyback converter required a unique pattern of PWM to optimize the power transfer in the magnetic circuit used in the converter. The three-phase PWM is generated digitally based on uniform symmetrical sampling technique using Xilinx chip. The generated PWM pattern is able to reduce the magnitude of the low order of harmonic components present in the input ac supply. Although software simulation could simulate the PWM pattern, it does not represent the exact pattern as being generated digitally. The mathematical approach used is to model …


A Low-Phase-Noise 18-Ghz-Band Frequency Synthesizer With Low Frequency Step Size, B. Biglarbegian, F. Hodjat Kashani, Hossein Ameri Mahabadi May 2006

A Low-Phase-Noise 18-Ghz-Band Frequency Synthesizer With Low Frequency Step Size, B. Biglarbegian, F. Hodjat Kashani, Hossein Ameri Mahabadi

Hossein Ameri Mahabadi

Due to development of both wireless communication users and communication line users, utilization of high-speed communications has become a vital essence. High speed digital microwave radios have a great contribution in wireless telecommunications. Having a different and high capacitance, these radios can transmit and receive data in point to point links in far distances up to 30 km. Considering the high rate of utilization such digital microwave radios have in lower bands, it is imperative to utilize such kind of radios in upper bandsfor accessing more channels. One of the radios that plays a significant role in communications is digital …


Diode Quad Is Foundation For Pin Diode Attenuator, Chin-Leong Lim Apr 2006

Diode Quad Is Foundation For Pin Diode Attenuator, Chin-Leong Lim

Chin-Leong Lim

Voltage-variable attenuators (VVAs) enable gain adjustment in a wide range of applications, including in cable-television (CATV), satellite-television (SATV) systems, and even test equipment and measurement systems. The PI VVA configuration using PIN diodes is ubiquitous in CATV and SATV systems owing to its low part count, small size, constant impedance, high linearity, and multi-decade bandwidth. Presently, there is a great pressure to miniaturize this VVA in order to shrink end-product size. To miniaturize this class of VVAs, we integrated four diodes into a five-pin, leadfree SOT-25 surface mount package. This paper describes the prototype VVA's design, fabrication and experimental results. …


An Enhancement Of Decimation Process Using Fast Cascaded Integrator Comb (Cic), Rozita Teymourzadeh, Masuri Othman Dec 2005

An Enhancement Of Decimation Process Using Fast Cascaded Integrator Comb (Cic), Rozita Teymourzadeh, Masuri Othman

Dr. Rozita Teymourzadeh, CEng.

The over sampling technique has been shown to increase the SNR and is used in many high performance system such as in the ADC for audio and DAT systems. This paper presents the design of the decimation and its VLSI implementation which is the sub-component in the over sampling technique. The design of three main units in the decimation stage that is the Cascaded Integrator Comb (CIC) filter, the associated half band filters and the droop correction are also described. The Verilog HDL code in Xilinx ISE environment has been derived to describe the CIC filter properties and downloaded in …


An Overview Of The Decimation Process And Its Vlsi Implementation, Rozita Teymourzadeh, Masuri Othman Dec 2005

An Overview Of The Decimation Process And Its Vlsi Implementation, Rozita Teymourzadeh, Masuri Othman

Dr. Rozita Teymourzadeh, CEng.

Digital Decimation process plays an important task in communication system. It mostly is applied in transceiver when the frequency reduction is required. However, the decimation process for sigma delta modulator is considered in this research work. The proposed design was simulated using MATLAB software and implemented by hardware description language in Xilinx environment. Furthermore, the proposed advance arithmetic unit is applied to improve the system efficiency.


An Improved Recursive And Non-Recursive Comb Filter For Dsp Applications, Rozita Teymourzadeh, Masuri Othman Dec 2005

An Improved Recursive And Non-Recursive Comb Filter For Dsp Applications, Rozita Teymourzadeh, Masuri Othman

Dr. Rozita Teymourzadeh, CEng.

The recursive and non-recursive comb filters are commonly used as decimators for the sigma delta modulators. This paper presents the analysis and design of low power and high speed comb filters. The comparison is made between the recursive and the non-recursive comb filters with the focus on high speed and saving power consumption. Design procedures and examples are given by using Matlab and Verilog HDL for both recursive and non-recursive comb filter with emphasis on frequency response, transfer function and register width. The implementation results show that non-recursive comb filter has capability of speeding up the circuit and reducing power …


Vlsi Implementation Of Cascaded Integrator Comb Filters For Dsp Applications, Rozita Teymourzadeh, Masuri Othman Dec 2005

Vlsi Implementation Of Cascaded Integrator Comb Filters For Dsp Applications, Rozita Teymourzadeh, Masuri Othman

Dr. Rozita Teymourzadeh, CEng.

The recursive comb filters or Cascaded Integrator Comb filter (CIC) are commonly used as decimators for the sigma delta modulators. This paper presents the VLSI implementation, analysis and design of high speed CIC filters which are based on a low-pass filter. These filters are used in the signal decimation which has the effect on reducing the sampling rate. It is also chosen because its attractive property of both low power and low complexity since it dose not required a multiplier. Simulink toolbox available in Matlab software which is used to simulator and Verilog HDL coding help to verify the functionality …