R. Hamzehyan Articles List

Open Access Article

1 - Evaluation of Temperature, Disturbance and Noise Effect in Full Adders Based on GDI Method
Hashem Arfavi Seyed Mohammadali Riazi Roozbeh Hamzehyan

10.30495/jce.2023.1973764.1197

20.1001.1.29809231.1402.13.50.4.5

In this paper, we limit our attention to full adders based on the GDI method, circuits that are commonly used in high-speed circuits and are more prone to noise. So far, a comprehensive review on noise immunity and ambient temperature change of full adders based on the More

In this paper, we limit our attention to full adders based on the GDI method, circuits that are commonly used in high-speed circuits and are more prone to noise. So far, a comprehensive review on noise immunity and ambient temperature change of full adders based on the GDI method has not been presented, and most of the studies have compared their proposed design with other full adders, which are mainly not based on the GDI method. These full adder cells were evaluated by various simulations such as supply voltage change, capacitive load change, ambient temperature change and process-voltage-temperature (PVT) changes in 45 nm CMOS technology. A noise immunity curve (NIC) was derived for full adder cells to identify better-performing full adder cells. The unity noise gain (UNG) was also investigated to evaluate the noise. Finally, a comprehensive comparison was made in terms of propagation delay, power consumption, power-delay product (PDP), voltage swing, sensitivity to process changes and noise for full adders based on the GDI method. The obtained results can be useful in the decisions of integrated circuit designers to choose the appropriate structure of the full adder based on the GDI method Manuscript profile

Open Access Article

2 - Investigating the performance of active vector and inductor capacitors in the resonant circuit of integrated VCOs with 0.18 µmCMOS technology
najmeh cheraghi shirazi Ebrahim Abiri Jahromi Roozbeh Hamzehyan

Using 0.18 µm technology, CMOS transistors are designed as a VCO prototype. In the proposed VCO structure, an adjustable active inductor and a vector for the LC tank are used. The wide frequency regulation in this circuit is controlled by an adjustable a More

Using 0.18 µm technology, CMOS transistors are designed as a VCO prototype. In the proposed VCO structure, an adjustable active inductor and a vector for the LC tank are used. The wide frequency regulation in this circuit is controlled by an adjustable active inductor and fine-tuning with a reactor.VCO with MOS vector in storage mode has the lowest power consumption and the lowest phase noise at large offset frequencies. The benefits of using MOS vectors increase significantly when more advanced CMOS technologies are selected. Due to the absence of passive elements, the fully integrated VCO takes up less chip surface area in the circuit. Manuscript profile

Open Access Article

3 - Evaluation of phase noise performance of voltage-controlled integrated inductors and active inductors with 0.18 µm CMOS technology
najmeh cheraghi shirazi Roozbeh Hamzehyan

A CMOS voltage controlled oscillator with a wide adjustment range is designed to operate at radio frequencies. The main advantage of this structure is the use of an active inductor. Hence the chip surface is significantly reduced. The active inductor and varactor c More

A CMOS voltage controlled oscillator with a wide adjustment range is designed to operate at radio frequencies. The main advantage of this structure is the use of an active inductor. Hence the chip surface is significantly reduced. The active inductor and varactor capacitor in the proposed VCO circuit is used for frequency settings. The results of the measurements using the 0.18 µm CMOS process show phase noise -79.85dBc and amplitude noise -126.9dBm in the 1MHz offset. Also, using the S parameter, the central frequency value for this 3GHz circuit is obtained. Manuscript profile

Open Access Article

4 - Blind speech signal separation based on cumulant approach
Sahar Pouya مصطفی Esmail Beyg R. Hamzehyan

One of the proposed methods for separating several speech signals, which are combined in receivers, is the use of blind source separation (BSS) methods. Resource blind separation is the separation and estimation of signals generated by sources in an unknown channel and More

One of the proposed methods for separating several speech signals, which are combined in receivers, is the use of blind source separation (BSS) methods. Resource blind separation is the separation and estimation of signals generated by sources in an unknown channel and their combinations received at receivers. Existing algorithms for blind source separation are often based on the special analysis of fourth-order cumulative matrices. However, when cumulative matrices have close eigenvalues, their eigenvectors become very sensitive to the error in estimating the matrices. In this paper, we try to reduce this sensitivity by using a new algorithm and obtain a more accurate estimate. Manuscript profile

Open Access Article

5 - Investigation of phase shift and channel frequency offset recovery in Godard blind equalizer algorithm
Roozbeh Hamzehyan

An equalizer is used to eliminate the effect of symbolic interference (ISI) in telecommunication channels. One of the equalizer methods that does not require the use of a training sequence is the Godard blind equalizer method. The efficiency of this method decreases sig More

An equalizer is used to eliminate the effect of symbolic interference (ISI) in telecommunication channels. One of the equalizer methods that does not require the use of a training sequence is the Godard blind equalizer method. The efficiency of this method decreases significantly in the case of distortion in the phase and frequency of the sent symbols. Therefore, the use of a phase lock loop (PLL) at the output of this equalizer is recommended to eliminate the phase shift and frequency offset added by the channel. In this paper, two types of first and second-order phase lock loops are investigated and confirmed by simulation. The first-order phase lock loop can only remove the fixed phase shift, and the second-order phase lock loop, in addition to the fixed phase shift, can also remove the channel offset frequency. Manuscript profile

Open Access Article

6 - The Comparison of Classification Algorithms for Remote Sensing Images
najmeh Cheraghi Shirazi Roozbeh Hamzehyan Ashkan Masoomi

Although a large number of remote sensing image classification algorithm is proposed, but rarely performance of them are compared with each other. In this research, we classify satellite remote sensing images using two unsupervised classification algorithm and eight sup More

Although a large number of remote sensing image classification algorithm is proposed, but rarely performance of them are compared with each other. In this research, we classify satellite remote sensing images using two unsupervised classification algorithm and eight supervised classification algorithm which includes a number of common algorithms twenty years, tested and compared.  Our analysis focused on satellite images of the 12 spectral bands.  In comparison of these algorithms, the number of training samples is equated. These algorithms are compared with each other in terms of complexity, accuracy and reliability. The results show that accuracy of classification directly proportion to the number of training samples. The user can also choose efficient algorithms, depending on the complexity, accuracy and reliability of each parameter. Manuscript profile

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