2016/2
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Recent Submissions
- ItemTriangle/Square Waveform Generator Using Area Efficient Hysteresis Comparator(Společnost pro radioelektronické inženýrství, 2016-06) Drinovsky, Martin; Hospodka, JiriA function generator generating both square and triangle waveforms is proposed. The generator employs only one low area comparator with accurate hysteresis set by a bias current and a resistor. Oscillation frequency and its non-idealities are analyzed. The function of the proposed circuit is demonstrated on a design of 1 MHz oscillator in STMicroelectronics 180 nm BCD technology. The designed circuit is thoroughly simulated including trimming evaluation. It consumes 4.1 μA at 1.8 V and takes 0.0126 mm2 of silicon area. The temperature variation from -40°C to 125°C is ±1.5 % and the temperature coefficient is 127 ppm/°C.
- ItemA Geometric Approach to Group Delay Network Synthesis(Společnost pro radioelektronické inženýrství, 2016-06) Osuch, Piotr Jan; Stander, TinusAll-pass networks with prescribed group delay are used for analog signal processing and equalisation of transmission channels. The state-of-the-art methods for synthesising quasi-arbitrary group delay functions using all-pass elements lack a theoretical synthesis procedure that guarantees minimum-order networks. We present an analytically-based solution to this problem that produces an all-pass network with a response approximating the required group delay to within an arbitrary minimax error. For the first time, this method is shown to work for any physical realisation of second-order all-pass elements, is guaranteed to converge to a global optimum solution without any choice of seed values as an input, and allows synthesis of pre-defined networks described both analytically and numerically. The proposed method is also demonstrated by reducing the delay variation of a practical system by any desired amount, and compared to state-of-the-art methods in comparison examples.
- ItemGrey Box Non-Linearities Modeling and Characterization of a BandPass BAW Filter(Společnost pro radioelektronické inženýrství, 2016-06) Mabrouk, Mohamed; Boujemaa, Mohamed-Ali; Choubani, FethiIn this work, the non-linearities of a 3G/UMTS geared BandPass Bulk Acoustic Wave ladder filter composed of five resonators were modeled using non-linear modified Butterworth-Van Dyke model. The non-linear characteristics were measured and simulated, and they were compared and found to be fairly identical. The filter's central frequency is 2.12 GHz, the corresponding bandwidth is 61.55 MHz, and the quality factor is 34.55.
- ItemEfficient Design of Digital FIR Differentiator using $L_1$-Method(Společnost pro radioelektronické inženýrství, 2016-06) Aggarwal, Apoorva; Rawat, T. K.; Kumar, Manjeet; Upadhyay, D. K.In this paper, an efficient design of FIR digital differentiator using the L1-optimality criterion is proposed. We present a technique based on the modified Newton method to solve the design problem so that the optimal differentiator coefficients are obtained by minimizing the absolute error. The novel L1-error function leads to a flat response at low-frequencies. Extensive simulations are carried out to validate the proposed design. The superiority of the proposed design is evident by comparing it with other conventional design techniques such as, windowing, minimax and the least-squares approach.
- ItemSegmentation of Moving Object Using Background Subtraction Method in Complex Environments(Společnost pro radioelektronické inženýrství, 2016-06) Kumar, Satrughan; Sen Yadav, JigyendraBackground subtraction is an extensively used approach to localize the moving object in a video sequence. However, detecting an object under the spatiotemporal behavior of background such as rippling of water, moving curtain and illumination change or low resolution is not a straightforward task. To deal with the above-mentioned problem, we address a background maintenance scheme based on the updating of background pixels by estimating the current spatial variance along the temporal line. The work is focused to immune the variation of local motion in the background. Finally, the most suitable label assignment to the motion field is estimated and optimized by using iterated conditional mode (ICM) under a Markovian framework. Performance evaluation and comparisons with the other well-known background subtraction methods show that the proposed method is unaffected by the problem of aperture distortion, ghost image, and high frequency noise.