scholarly journals I/Q Linear Phase Imbalance Estimation Technique of the Wideband Zero-IF Receiver

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1787
Author(s):  
Jie Meng ◽  
Houjun Wang ◽  
Peng Ye ◽  
Yu Zhao ◽  
Lianping Guo ◽  
...  
Keyword(s):  
Communication Systems ◽  
Estimation Method ◽  
Digital Signal ◽  
Local Oscillator ◽  
Linear Phase ◽  
Matlab Simulation ◽  
Image Rejection ◽  
Receiver System ◽  
Before And After ◽  
Image Rejection Ratio

The in-phase/quadrature (I/Q) imbalance encountered in the zero-IF receiver leads to incomplete image frequency suppression, which severely deteriorates image rejection ratio (IRR) of the receiver system and must be improved using additional analog or digital signal processing. The I/Q linear phase imbalance (LPI) is the key of the I/Q imbalance, which consists of the time delay deviation (TDD) and the local oscillator (LO) phase offset. TDD is negligible in most literature, but it degrades system performance largely for wideband communication systems. This paper proposes a method based on the cross-power spectrum between the I/Q signal to address the estimation problem of LPI. Compared with other conventional methods, the proposed approach calculates LPI parameters simultaneously without any additional hardware. The MATLAB simulation is utilized to evaluate the effectiveness of the presented method. Moreover, the experimental platform of detailed design demonstrates the feasibility of the proposed estimation method, and IRR of the system before and after compensation shows that LPI has been accurately estimated and eliminated with the help of an appropriate compensation structure. Both reveal that the proposed method offers an effective solution to the LPI problem.

scholarly journals Análisis de la técnica UFMC en un canal multitrayecto y usando estimación de canal

2021 ◽  
Vol 9 (17) ◽  
pp. 26-39
Author(s):  
Hugo Wladimir Iza Benítez ◽  
Diego Javier Reinoso Chisaguano
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Filter Bank ◽  
Estimation Method ◽  
Wireless Communication Systems ◽  
Ofdm Systems ◽  
Matlab Simulation ◽  
Fifth Generation ◽  
Power Spectral ◽  
Filter Bank Multicarrier

UFMC (Universal Filtered Multi-Carrier) is a novel multi-carrier transmission technique that aims to replace the OFDM (Orthogonal Frequency Division Multiplexing) modulation technique for fifth generation (5G) wireless communication systems. UFMC, being a generalization of OFDM and FBMC (Filter Bank Multicarrier), combines the advantages of these systems and at the same time avoids their main disadvantages. Using a Matlab simulation, this article presents an analysis of the robustness of UFMC against fading effects of multipath channels without using a CP (cyclic prefix). The behavior of the UFMC system is analyzed in terms of the PSD (Power Spectral Density), BER (Bit Error Rate) and MSE (Mean Square Error). The results show that UFMC reduces the out-band side lobes produced in the PSD of the processed signal. Also, it is shown that the pilot-assisted channel estimation method applied in OFDM systems can also be applied in UFMC systems.

scholarly journals DESIGN OF FREQUENCY INDEPENDENT DIGITAL IQ IMBALANCE COMPENSATOR FOR RECEIVERS

2018 ◽  
pp. 40-48
Author(s):  
I. Yu. Gridin
Keyword(s):  
Digital Signal ◽  
Signal Quality ◽  
Ratio Estimation ◽  
Image Rejection ◽  
Rejection Ratio ◽  
Iq Imbalance ◽  
Analog Front End ◽  
Frequency Independent ◽  
Negative Effect ◽  
Image Rejection Ratio

Derivation of IQ imbalance in IQ receivers because of non-idealities of analog front-end has a significant negative effect on received signal quality and serious RF system performance degradation. Thereat the RF designers have an objective to create and improve compact and stand-alone methods of IQ imbalance compensation which provide best possible Image Rejection Ratio (IRR). The DSP-based methods of compensation are the most perspective. In this paper described one of version of autonomous and adaptive frequency independent IQ imbalance compensation algorithm which can be implemented as an IP that which can be used in different SoC for RF applications. The calculation method is based on digital signal statistic estimation with real-time convergence of compensation coefficients to the goal values which provide best image rejection. The results of algorithm’s processing for different input values with different IQ imbalance values are presented with max and min image rejection ratio estimation.

Optimization Design on Power Filter of TCR Under Asymmetrical Voltage

2015 ◽  
Vol 9 (1) ◽  
pp. 591-599
Author(s):  
Ma Wenchuan ◽  
Zhitong Li ◽  
Chen Daochang ◽  
Qi Jiaming ◽  
Zhou Qiang ◽  
...  
Keyword(s):  
Optimization Design ◽  
Reactive Power ◽  
Estimation Method ◽  
Reactive Power Compensation ◽  
Harmonic Suppression ◽  
Matlab Simulation ◽  
Steel Mill ◽  
Harmonic Current ◽  
Third Harmonic ◽  
Power Filter

For resolving the problem that power filter cannot work normally because TCR (thyristor controlled reactor) generates extra third harmonic current under asymmetrical voltage, the paper proposes the estimation method of current capacity that TCR generates extra third harmonic current under asymmetrical voltage. Considering extra third harmonic current under asymmetrical voltage, Optimum method based on genetic algorithm is used to design the parameters of power filter. With reactive power compensation and harmonic suppression project of a steel mill as example, the proposed method is simulated by Matlab. Simulation results show optimized power filter can eliminate extra third harmonic current effects under asymmetrical voltage, meet the requirement of reactive power compensation, reduce harmonics current that load injects into system, and guarantee the power filter safe operation under asymmetrical voltage.

scholarly journals Low-complexity beam-domain channel estimation and power allocation in hybrid architecture massive MIMO systems

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Xiao Chen ◽  
Zaichen Zhang ◽  
Liang Wu ◽  
Jian Dang
Keyword(s):  
Channel Estimation ◽  
Power Allocation ◽  
Spectral Efficiency ◽  
Communication Systems ◽  
Mimo Systems ◽  
Beam Steering ◽  
Estimation Method ◽  
Low Complexity ◽  
Estimation Accuracy ◽  
Hybrid Architecture

Abstract In this journal, we investigate the beam-domain channel estimation and power allocation in hybrid architecture massive multiple-input and multiple-output (MIMO) communication systems. First, we propose a low-complexity channel estimation method, which utilizes the beam steering vectors achieved from the direction-of-arrival (DOA) estimation and beam gains estimated by low-overhead pilots. Based on the estimated beam information, a purely analog precoding strategy is also designed. Then, the optimal power allocation among multiple beams is derived to maximize spectral efficiency. Finally, simulation results show that the proposed schemes can achieve high channel estimation accuracy and spectral efficiency.

scholarly journals Analysis of Non-Idealities on CMOS Passive Mixers

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1105
Author(s):  
Antonio D. Martinez-Perez ◽  
Francisco Aznar ◽  
Guillermo Royo ◽  
Santiago Celma
Keyword(s):  
Final Section ◽  
Cmos Technology ◽  
Monte Carlo Analysis ◽  
Image Rejection ◽  
Structure Approach ◽  
Quadrature Scheme ◽  
Current State ◽  
The Cost ◽  
Image Rejection Ratio ◽  
The Ideal

In the current state of the art, WiFi-alike standards require achieving a high Image Rejection Ratio (IRR) while having low power consumption. Thus, quadrature structures based on passive ring mixers offer an attractive and widely used solution, as they can achieve a high IRR while being a passive block. However, it is not easy for the designer to know when a simple quadrature scheme is enough and when they should aim for a double quadrature structure approach, as the latter can improve the performance at the cost of requiring more area and complexity. This study focuses on the IRR, which crucially depends on the symmetry between the I and Q branches. Non-idealities (component mismatches, parasitics, etc.) will degrade the ideal balance by affecting the mixer and/or following/previous stages. This paper analyses the effect of imbalances, providing the constraints for obtaining a 40 dB IRR in the case of a conversion from a one-hundred-megahertz signal to the five-gigahertz range (upconversion) and vice versa (downconversion) for simple and double quadrature schemes. All simulations were carried out with complete device models from 65 nm standard CMOS technology and also a post-layout Monte Carlo analysis was included for mismatch analysis. The final section includes guidelines to help designers choose the most adequate scheme for each case.

Interaction of Speech Coders and Atypical Speech II

2002 ◽  
Vol 45 (4) ◽  
pp. 689-699 ◽  
Author(s):  
Donald G. Jamieson ◽  
Vijay Parsa ◽  
Moneca C. Price ◽  
James Till
Keyword(s):  
Communication Systems ◽  
Speech Rate ◽  
Voice Quality ◽  
Voice Disorders ◽  
Normal Hearing ◽  
Speech Quality ◽  
Degraded Speech ◽  
Before And After ◽  
Subband Processing

We investigated how standard speech coders, currently used in modern communication systems, affect the quality of the speech of persons who have common speech and voice disorders. Three standardized speech coders (GSM 6.10 RPELTP, FS1016 CELP, and FS1015 LPC) and two speech coders based on subband processing were evaluated for their performance. Coder effects were assessed by measuring the quality of speech samples both before and after processing by the speech coders. Speech quality was rated by 10 listeners with normal hearing on 28 different scales representing pitch and loudness changes, speech rate, laryngeal and resonatory dysfunction, and coder-induced distortions. Results showed that (a) nine scale items were consistently and reliably rated by the listeners; (b) all coders degraded speech quality on these nine scales, with the GSM and CELP coders providing the better quality speech; and (c) interactions between coders and individual voices did occur on several voice quality scales.

Sensorless Control of IPMSM Using Modified Current Slope Estimation Method

2012 ◽  
Vol 150 ◽  
pp. 100-104
Author(s):  
Tao Zhang ◽  
Wei Ni ◽  
Hui Ping Zhang ◽  
Sha Sha Wu
Keyword(s):  
Permanent Magnet ◽  
Digital Signal Processor ◽  
Permanent Magnet Synchronous Motor ◽  
Estimation Method ◽  
Digital Signal ◽  
Synchronous Motor ◽  
Low Speed ◽  
Rotor Position ◽  
Operating Region ◽  
Interior Permanent Magnet

When the permanent magnet synchronous motor is operated at a low speed. The rotor position and speed are very difficult to estimate using the extended flux or back EMF method. A novel modified current slope estimating method is used to estimate the rotor position and speed in low speed in this paper. The mathematical models of an interior permanent magnet synchronous motor (IPMSM) are deduced. The basic principle of modified current slope method is introduced. The simulation control system is built based on Matlab and a TMS320LF2407 digital signal processor is used to execute the rotor position and speed estimation. The experimental and simulation results have shown that the rotor position and speed can be accurately estimated in a low-speed operating region.

scholarly journals Voice re-education and its evaluation through digital signal processing: A case study

Loquens ◽  
2017 ◽  
Vol 4 (1) ◽  
pp. 040
Author(s):  
Zulema Santana-López ◽  
Óscar Domínguez-Jaén ◽  
Jesús B. Alonso ◽  
María Del Carmen Mato-Carrodeguas
Keyword(s):  
Voice Quality ◽  
Quality Measurement ◽  
Digital Signal ◽  
Communication Process ◽  
Time Frequency ◽  
Voice Signal ◽  
Functional Dysphonia ◽  
Before And After ◽  
Voice Pathologies ◽  
The Voice

Voice pathologies, caused either by functional dysphonia or organic lesions, or even by just an inappropriate emission of the voice, may lead to vocal abuse, affecting significantly the communication process. The present study is based on the case of a single patient diagnosed with myasthenia gravis (Erb-Goldflam syndrome). In this case, this affection has caused, among other disruptions, a dysarthria. For its treatment, a technique for the education and re-education of the voice has been used, based on a resonator element: the cellophane screen. This article shows the results obtained in the patient after applying a vocal re-education technique called the Cimardi Method: the Cellophane Screen, which is a pioneering technique in this field. Changes in the patient’s voice signal have been studied before and after the application of the Cimardi Method in different domains of study: time-frequency, spectrum, and cepstrum. Moreover, parameters for voice quality measurement, such as shimmer, jitter and harmonic-to-noise ratio (HNR), have been used to quantify the results obtained with the Cimardi Method. Once the results were analyzed, it has been observed that the Cimardi Method helps to produce a more natural and free vocal emission, which is very useful as a rehabilitation therapy for those people presenting certain vocal disorders.

scholarly journals Reversible logic in pipelined low power vedic multiplier

2019 ◽  
Vol 16 (3) ◽  
pp. 1265
Author(s):  
Ansiya Eshack ◽  
S. Krishnakumar
Keyword(s):  
Low Power ◽  
Communication Systems ◽  
Large Scale ◽  
Optical Computing ◽  
Digital Signal ◽  
Logic Gates ◽  
Reversible Logic ◽  
Large Scale Integration ◽  
Time Required ◽  
Scale Integration

<span>With an ever growing demand for low-power devices, it is a general trend to search for ways to reduce the power consumption of a system. Multipliers are an important requirement in applications linked to Digital Signal Processing, Communication Systems, Optical Computing, Nanotechnology, Low-Power Very Large Scale Integration and Quantum Computing. Conventional mathematics makes multiplication a very long and time consuming process. The use of Vedic mathematics has led to great reduction in the time required for such calculations. The excessive use of Urdhava Tiryakbhyam sutra in multiplication surely proves its effectiveness and simplicity in this domain. This sutra supports the process of pipelining, a method employed in reduction of the power used by a system. Reversible logic has been gaining demand due to its low-power capabilities and is currently being used in many computing applications. The paper proposes two multiplier systems: one design employs the Urdhava Tiryakbhyam sutra along with pipelining and the second uses reversible logic gates into the first design. These proposed systems provide very less delay for result computation and low hardware utilization when compared to non-pipelined Vedic multipliers.</span>

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