2011/4

Browse

Recent Submissions

Now showing 1 - 5 of 41
  • Thumbnail Image
    Item
    Analysis and Simulation of the Transmission Distortions of the Mobile Digital Television DVB-SH Part 1: Terrestrial Mode DVB-SH-A with OFDM
    (Společnost pro radioelektronické inženýrství, 2011-12) Polak, Ladislav; Kratochvil, Tomas
    This paper deals with the latest digital TV standard DVB-SH (Digital Video Broadcasting - Satellite to Handhelds) with focus on utilization of its advantages for the next generation of mobile TV broadcasting. The whole paper consists of two parts. In this first part, after the brief introduction to DVB-SH and related last works review, the simulation model of DVB-SH-A, which is using terrestrial configuration with OFDM transmission mode, is presented. The work is especially focused on the description of new type of forward error correction and system configuration of the DVB-SH-A mode. For the analysis and simulation of the transmission, the original scheme of turbo encoder was modified in this paper. Application for simulation of the transmission in mobile and portable fading transmission channels was developed in MATLAB. Dependences of BER on C/N ratio for all types of payload modulation are compared with focus on mobile TV services availability. Finally, the achieved results are evaluated and clearly discussed.
  • Thumbnail Image
    Item
    An Automatic Technique for MRI Based Murine Abdominal Fat Measurement
    (Společnost pro radioelektronické inženýrství, 2011-12) Tang, Yang; Simerly, Richard; Moats, Rex A.
    Because of the well-known relationship between obesity and high incidence of diseases, fat related research using mice models is being widely investigated in preclinical experiments. In the present study, we developed a technique to automatically measure mice abdominal adipose volume and determine the depot locations using Magnetic Resonance Imaging (MRI). Our technique includes an innovative method to detect fat tissues from MR images which not only utilizes the T1 weighted intensity information, but also takes advantage of the transverse relaxation time(T2) calculated from the multiple echo data. The technique contains both a fat optimized MRI imaging acquisition protocol that works well at 7T and a newly designed post processing methodology that can automatically accomplish the fat extraction and depot recognition without user intervention in the segmentation procedure. The post processing methodology has been integrated into easy-to-use software that we have made available via free download. The method was validated by comparing automated results with two independent manual analyses in 26 mice exhibiting different fat ratios from the obesity research project. The comparison confirms a close agreement between the results in total adipose tissue size and voxel-by-voxel overlaps.
  • Thumbnail Image
    Item
    BPSK Receiver Based on Recursive Adaptive Filter with Remodulation
    (Společnost pro radioelektronické inženýrství, 2011-12) Dimitrijevic, Bojan; Milosevic, Nenad; Marsalek, Roman; Nikolic, Zorica
    This paper proposes a new binary phase shift keying (BPSK) signal receiver intended for reception under conditions of significant carrier frequency offsets. The recursive adaptive filter with least mean squares (LMS) adaptation is used. The proposed receiver has a constant, defining the balance between the recursive and the nonrecursive part of the filter, whose proper choice allows a simple construction of the receiver. The correct choice of this parameter could result in unitary length of the filter. The proposed receiver has performance very close to the performance of the BPSK receiver with perfect frequency synchronization, in a wide range of frequency offsets (plus/minus quarter of the signal bandwidth). The results obtained by the software simulation are confirmed by the experimental results measured on the receiver realized with the universal software radio peripheral (USRP), with the baseband signal processing at personal computer (PC).
  • Thumbnail Image
    Item
    Realization of Resistorless Wave Active Filter using Differential Voltage Current Controlled Conveyor Transconductance Amplifier
    (Společnost pro radioelektronické inženýrství, 2011-12) Pandey, Neeta; Kumar, Praveen
    In this paper, a resistorless realization of high order voltage mode wave active filter based on Differential Voltage current controlled conveyor transconductance amplifier (DVCCCTA) is presented. The wave method is used for simulating reflected and incident wave for basic building block i.e. series inductor and configuring it for other passive element realization by making appropriate connection. The proposed structure uses grounded capacitors and possesses electronic tunability of cutoff frequency. The proposed approach is verified for a 4th order low pass filter through SPICE simulation using 0.25µm TSMC CMOS technology parameters.
  • Thumbnail Image
    Item
    Efficient Algorithm for Power Allocation in Relay-based Cognitive Radio Network
    (Společnost pro radioelektronické inženýrství, 2011-12) Ferdous, N.; Ahmed, M.; Matin, M. A.; Habiba, U.
    This paper addresses a cognitive radio (CR) network scenario where a relay is assigned to mitigate interference to primary users (PUs). We develop an average probability of successful secondary transmission (PSST) to introduce relay in the CR network. The power allocation is done using dual domain concept to maximize the system throughput as well as maintaining interference to an acceptable level and this approach is implemented in our paper that has a higher convergence rate. Furthermore, we propose an alternative approach that maintains a high throughput and at the same time reduces the computational complexity significantly. A detailed analysis is done before simulation. The simulated results validate the theoretical analysis.