Recent Patents on Electrical & Electronic Engineering - Volume 6, Issue 2, 2013

In this paper, a review of the major evolution steps of mobile transmitter architectures is summarized. We propose a classification and discuss about improvements and evolutions towards the full-digital solutions. This discussion is mandatory while the cognitive-radio concept implies the design of new structures for multi-radio front-ends. Technological process improvements, for example CMOS for high frequency, opens new possible solutions thanks to digitally based buildings blocks and functions. The conception of fully digital architectures is discussed in that idea. Our work in this domain is presented as a contribution in the study of transmitter architecture for multi-radio. Two ways are explored: (1) improvements of analog and digitized architectures, and (2) digital architectures. We present, in these two fields, a state of the art of published works and patents [US20130051440A1], [US20130084816A1], [US20120320957A1]. The Multiradio context drives us to redefine the important figures of merit for the architecture design, as seen in recent publications and patents such as [US20130049854A1], [US20130009710A1], [US8432219], [EP2541781A1]. The traditional efficiency/ linearity trade-off has to be considered with a mandatory frequency flexibility and power control ability, defined here as “power scale-ability”. These constraints made the conception of fully digital architectures attractive, thanks to the flexibility of digital systems. The first part of this paper will present the challenges of designing transmitter architectures for cellular and wireless local/extended area networks (WLAN and WIMAX for example), under the hypothesis of nomadic communication system. The design method in that context is consequently different from classical architecture design. In the second part, a classification of the RF transmitter architectures and their evolution are proposed. Evolution from linearization to linear architectures and introduction of digitized functions are presented, in that order. Solutions are appreciated differently, considering the multiple tradeoffs on efficiency, linearity, flexibility and complexity, while taking into account integration and realization (process).

During the last decade, spread spectrum techniques have become more and more popular in the field of mobile communication systems. In particular, satellite systems (GPS and Galileo) as well as the third generation radio mobile system have adopted the direct sequence spread spectrum as the communication technology of the physical layer. The receiver must first perform a code acquisition and then maintain a fine synchronization with the transmitter, to exploit all the advantages of the spread spectrum technique. This paper aims at presenting a review of recent patents, and state of art solutions as well, in the field of code acquisition and synchronization for spread spectrum systems. Finally, a discussion pointing out the current and future developments in this area summarizes the remarkable points of this work.

The recent discovery of the first modern prototype of the 4th fundamental circuit element by HP Laboratories turned the attention of both academia and industry to today’s broad classification of resistance switching devices, known as memristive devices and systems. The variety of applications which have been proposed recently, ranging from memory and reconfigurable architectures to neuromorphic learning and computing, is characteristic of the intense developing interest of these novel electronic devices which show excellent scalability, fast switching speed, long retention time and endurance. The primary purpose of this short review is to summarize and discuss a set of recent patents describing the progress towards the implementation of novel computational architectures, comprising memristive elements, and their applications, where the favorable characteristics of memristors and their nonvolatility are exploited.

Recent patents and approaches of symbol timing and frequency offset estimation in optical OFDM systems are reviewed. The synchronization methods utilizing the training sequence or cyclic prefix are discussed and compared. The processing approaches includes subtraction, low-power DC offset, auto- and cross-correlation schemes.The synchronization methods have been evaluated in terms of the efficiency and complexity. It is shown that, by determining the optimal length of the non-zero pattern of the training sequence, synchronization algorithm using simplified auto-correlation scheme can achieve both of the accuracy and low complexity for optical OFDM systems.

A bias generation scheme for CMOS cascode current mirrors is proposed. The bias voltage generated is equal to the sum of the overdrive voltage of the mirroring transistor and the gate source voltage of the cascode transistor. The proposed scheme is designed in a 65n m n-well CMOS process with 1.8V supply and simulation results are provided for different process corners. The proposed idea is also found in the patent [1].

In this study, the employment of permanent magnet (PM) in linear switched reluctance motor (LSRM) is studied in order to find the less cogging force construction with respect to an enhanced propulsion force. First, the three types are considered for the proposed structure and PM is added in the pole of the moveable part of LSRM. Then, PM width is increased till it covers all surface of the pole. After that, the propulsion force, the average propulsion force and the cogging force are used to calculate two criteria for evaluating the proposed structures compared to the conventional structure. Finally the optimum structure is chosen using two criteria which are the least cogging force and the improved propulsion force. This process also can be extended for rotary switched reluctance motors (RSRMs). Finite element analysis (FEA) is used to calculate the inductance, the permanent magnet flux linkage, and the cogging force. This paper also presents some patents about the LSRM which can operate as generator and multiple phase LSRM.

The main aim of this paper is to introduce a robust method for distance enhancing of a narrow band digital multipoint communication system. Despite the conventional power line carrier technologies and communicating standards such as EIA – 485, the large signal definition of the Frequency and Amplitude combined Modulations in Power Line Communication (FAMPLC) eliminates the requirement of any repeater facility for the distant access. In this paper, the Frequency Modulated Power Supply (FMPS) in one end and active resistances as dummy loads at the other ends to establish full – duplex large signal power line communication in independent voltage and current layers are presented. The design methodology, data extraction methods and error compensation techniques that resulted in a successful development are discussed. The article presents some promising patents on full duplex digital multipoint systems using large signal power line communication.

In this paper, some of the most recent patents about the switching regulators that use both PWM (Pulse Width Modulation) and PFM (Pulse Frequency Modulation) to improve the efficiency are introduced. The proper switching between the modes as one of the major design concerns is reviewed. Also, a novel architecture that helps to reduce the number of the inductors in SIMO (Single Input Multiple Outputs) systems is introduced. In addition, two patents about the gate drivers are recommended to improve the gate drive efficiency.