2009/4

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    High-Order Current-Mode and Transimpedance-Mode Universal Filters with Multiple-Inputs and Two-Outputs Using MOCCIIs
    (Společnost pro radioelektronické inženýrství, 2009-12) Horng, Jiun-Wei
    A high-order current-mode and transimpedance-mode universal filter with multiple-inputs and two-outputs based on multiple output second-generation current conveyors (MOCCIIs) is introduced. By choosing the input current terminals appropriately, the current-mode and transimpedance-mode lowpass, bandpass, highpass, notch or allpass filters can be obtained without component matching conditions. The proposed nth order universal filter requires (n+1) MOCCIIs, (n+1) resistors and n grounded capacitors. As examples, the first-order, biquadratic and third-order universal filters are given and compared with previous published works.
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    Audio Surveillance through Known Event Classification
    (Společnost pro radioelektronické inženýrství, 2009-12) Grezl, Frantisek; Cernocky, Jan
    The way of audio surveillance through known event classification is presented introducing simple yet efficient framework. The use of the proposed system for unknown event detection is also suggested and evaluated. Further, a specific audio event is detected with use of audio classification, which helps the detection to focus on a signal of specific behavior. Thus it is shown that the system can be used in several applications.
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    A CPW-Fed Novel Planar Ultra-Wideband Antenna with a Band-Notch Characteristic
    (Společnost pro radioelektronické inženýrství, 2009-12) Yu, Fei; Wang, Chunhua
    A coplanar waveguide (CPW) fed novel planar ultra-wideband antenna with a band-notch characteristic is presented. The proposed antenna consists of a rectangular metal radiation patch and a tapered arc-shaped ground plane. To achieve ultra wideband, three modifications are introduced, the first one is to remove a 90-degree fan angle on the upper corners of the patch, the second one is to shape the bottom of the patch into an arc, and the third modification is to remove a small fan angle on each side of the ground plane near the feeding line. Simulation results show that the proposed antenna operates over 3.0 to 23 GHz for VSWR < 2. By embedding a C-shaped slot in the radiating patch, a frequency band notch between the bandwidth of 5 to 6 GHz for Wireless LAN (WLAN) will be obtained. All simulations in this work were carried out by using the electromagnetic software Ansoft HFSS 11. Compared with the recently proposed antennas, this antenna has advantages in wide bandwidth, good band-notch characteristic, compact in size and easy design. Details of the proposed antenna are presented, and simulated results show that the antenna has stable radiation patterns and good gain flatness over its whole frequency band.
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    Maximum Available Accuracy of FM-CW Radars
    (Společnost pro radioelektronické inženýrství, 2009-12) Ricny, Vaclav
    This article deals with the principles and above all with the maximum available measuring accuracy analyse of FM-CW (Frequency Modulated Continuous Wave) radars, which are usually employed for distance and velocity measurements of moving objects in road traffic, as well as air traffic and in other applications. These radars often form an important part of the active safety equipment of high-end cars – the so-called anticollision systems. They usually work in the frequency bands of mm waves (24, 35, 77 GHz). Function principles and analyses of factors, that dominantly influence the distance measurement accuracy of these equipments especially in the modulation and demodulation part, are shown in the paper.
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    Traction Permanent Magnet Synchronous Motor Torque Control with Flux Weakening
    (Společnost pro radioelektronické inženýrství, 2009-12) Dolecek, Radovan; Novak, Jaroslav; Cerny, Ondrej
    The paper deals with analysis of dynamic behavior of a feedback flux weakening control of PMSM traction drive for light vehicles. The PMSM flux weakening is very important for traction drives. Two torque control structures were analyzed - pure feedback control and feedback control with prediction of the field producing current component. The principles, control structures, simulation and experimental results are given.