Browsing by Author "Agbemenu, Andrew Selasi"

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    Design of a fully integrated VHF CP-PLL frequency synthesizer with an all-digital defect-oriented built-in self-test
    (The Journal of Engineering, 2022-10-28) Kommey, Benjamin; Boateng, Kwame Osei; Yankey, Jephthah; Addo, Ernest Ofosu; Agbemenu, Andrew Selasi; Tchao, Eric Tutu; Akowuah, Bright Yeboah
    This paper presents the design of an on-chip charge pump phase-locked loop (CP-PLL) with a fully digital defect-oriented built-in self-test (BIST) for very-high frequency (VHF) applications. The frequency synthesizer has a 40–100 MHz tuning range and uses a ring voltage-controlled oscillator for frequency synthesis. The PLL exhibits a phase noise of −132 dBc/Hz at 1 MHz and consumes 1.8mWon a 3 V supply. The BIST implementation uses fewer external input or output, is capable of efficient fault diagnosis, and is compact, posing a low area overhead. The integrated circuit design was realized in the AMI 0.6μ complementary metal-oxide-semiconductor process.
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    Pulse Propagation in Multiaccess Wireline Channels
    (2011-06-19) Agbemenu, Andrew Selasi
    In telecommunication, a lot of measurements and models are perfomed in the time domain. Time domain analysis are usually complex and difficult difference equations are employed. Frequency Domain Models reduce the complexity of some of the mathematics to simplier arithmetic and convolution where necessary. In this thesis, Frequency Domain Modeling is used to come up with two models; Voltage Propagation Model (VPM) and the Current Propagation Models (IPM). The graph analysis is done in the time domain. Python, a powerful array manipulation programming language with third party scientific libraries: scipy, numpy and matplotlib, is used in the programming of the model. Since most models do not integrate GUI for easy testing, a GUI is also incoporated using Nokia’s Qt framework. The simulation results show that both the voltage and current pulses behave in similar ways. The attenuation and distortion of the pulses increases with decrease in the pulse width (increase frequency of propagation). The attenuation of the pulses also increases with increase in the number of taps on the transmission line.