The automatic calibration circuit, which is the main contribution of this thesis, operates while the transmitter is in service. This online calibration eliminates the need for production calibration and periodic down time for calibration cycles.
Description Thesis Ph. Date issued Department Massachusetts Institute of Technology. Publisher Massachusetts Institute of Technology.
Keywords Electrical Engineering and Computer Science. Electrical Engineering and Computer Sciences - Ph. A digital filter having the equivalent inverse- G s TF shown in 3 compensates for the low-pass property of the PLL and widens the signal path. Baseband digital phase is converted to RF analog phase by controlling the fractional division ratio via the DSM. Under symbol rate of The algorithm typically converges to a very small deviation after 10th or 11th iteration.
Therefore, times iteration is enough for the conversion resolution.
Fractional-N Phase Locked Loops and It’s Application in the GSM System | SpringerLink
For the given five consecutive phase component inputs, a derivation algorithm using a five-point-interpolation method with phase jump preprocess is shown in 7 under a sampling clock of 6. Figure 5 gives the simulated baseband components for EDGE signal. Both the envelope component with an amplitude range of 0. A peak frequency occurs when the envelope has a local minimum [ 2 ].
Since the fractional-N PLL has a low-passed feature with additional FIR attenuation, digital compensation filters need to be designed not only to compensate for the limited path bandwidth caused by the PLL but also to offset the gain attenuation due to the FIR filtering:. However, the ideal inverse-FIR filter conforming to 8 , is prone to instabile response with 14th-order high-passed feature.
Under 6. The circuit-level simulation results in frequency response for both ideal and proposed inverse-FIR filters are depicted in Figure 6. The proposed implementation is simple and stabile with slight overshoot but has the same compensation feature within desired frequency band, when compared to the ideal one.
Simulated frequency responses of FIR-compensated filters: ideal versus proposed implementations. To ensure the compensation filter stable, additional 3 poles with farther locations are added to the inverse- G s filter, without affecting the frequency response within the desired frequency band. To further simplify filters, the proposed 3rd-order inverse-FIR and 4th-order inverse- G s filters are combined together by employing a 7th-order infinite-impulse-response IIR digital filter with a high-pass property.
Figure 7 shows the simulated frequency response of the presented phase modulator. The frequency component f in , divided by F ref and then amplified by the IIR filter, is small enough for the DSM input not to cause overflow. To ensure phase-modulation linearity, it is important to ensure strict match of the TFs between the inverse- G s filter and the fractional-N PLL. With embedded FIR filtering, the 4th-order type-II PLL with kHz bandwidth employs eight PFDs in parallel, and all the lead-lag phase errors converted to push-pull pulse currents are summed at the output of the 8-phase charge pump.
The schematic of the 8-phase charge pump is shown in Figure 8. Cascode biasing architecture helps to reduce switching noise from the multiple current switches and improves static and dynamic current match between the up and down branches. The summed push-pull error current is low-passed filtered to generate an error control voltage V C , which tunes the sequent VCO shown in Figure 9.
LOW PHASE NOISE CMOS PLL FREQUENCY SYNTHESIZER DESIGN AND ANALYSIS
The VCO employs the conventional cross-coupled three-transistor differential architecture with LC tank. An inductor L 3 is inserted between the current source M2 and the cross-couple pair M3-M4 to reduce the second-order harmonic noise, and the embedded RC LPF suppresses the bias noise. Figure 10 shows phase shifter PS based MMD [ 9 , 14 ] module to provide a programmable division ratio of 64— controlled by the baseband phase signal via the DSM. The CML divider-by-4 is composed of two-stage cascaded dividers-by Figure 11 gives the schematic of the CML divider-by-2, which is similar to two-stage cross-coupled latch architecture.
The suggested method is simple and efficient, and is applicable to the joint operation of different sequence separation techniques and the SRF- PLL. The effectiveness The prototype is being developed. The continuous development of the digital processing technology made advanced control strategies available for switched-mode power-supply applications. Titanium and its alloys are frequently used as surgical implants in load bearing situations, such as hip prostheses and dental implants, owing to their biocompatibility, mechanical and physical properties. In this paper, a layer-by-layer LBL self-assembly technique, based on the polyelectrolyte-mediated electrostatic adsorption of poly-L-lysine PLL and DNA, was used to the formation of multilayer on titanium surfaces.
Then bovine serum albumin BSA adsorption and biomimetic mineralization of modified surfaces were studied. The chemical composition and wettability of assembled substrates were investigated by X-ray photoelectron spectroscopy XPS , fluorescence microscopy and water contact angle measurement, respectively. The XPS analysis indicated that the layers were assembled successfully through electrostatic attractions.
Thus the assembling of PLL and DNA onto the surface of titanium in turn via a layer-by-layer self-assembly technology can improve the bioactivity of titanium. PCIe buses require efficient clock data recovery circuits CDR to recover clock signals embedded in data during transmission. The effect of jitter on the proposed design is also simulated and evaluated in this work. It was found that the proposed design is robust against both input and VCO jitter.
Protokol persisian komponen sambung tara ekspres PCIe mengendalikan semua komunikasi antara unit pemprosesan pusat CPU dan peranti perkakasan. Bas PCIe memerlukan litar jam pemulihan data CDR yang cekap untuk mendapatkan kembali isyarat jam yang tertanam dalam data semasa transmisi.
Simulasi telah dijalankan menggunakan perisian verilog-AMS. Simulasi mengunnakan kesan ketar dalam reka bentuk yang dicadangkan telah dinilai. Reka bentuk yang dicadangkan terbukti teguh mengatasi ganguan ketar di input dan VCO. While protein adsorption was minimized, we found considerable adsorption of polysaccharides, and exposure to DNA resulted in complete desorption These results explain why S. Polymer brush coatings of poly ethylene glycol are considered the gold standard for nonfouling surfaces, but nevertheless, a few bacteria manage to attach and initiate biofilm formation on these coatings.
To achieve robust resistance against bacterial adhesion and biofilm formation, grafting It was designed and simulated for frequency range 10 MHz—3. Four division factors i. Preliminary measurements done in frequency range 20 MHz—1. The automatic VCO mode switching, one of the main design goals, was positively verified.
Power consumption of around 0. Simple and effective pre-emphasis and equalizer circuits are used at transmitter and receiver, respectively. A phase interpolator based clock and data recovery circuit with optimized linearity is a Problems with power quality in the grid have gained a lot of attention recently due to rapid increase in the amount of grid-connected power converters. The converter should produce sinusoidal currents also during abnormal conditions, such as unbalanced grid voltages. Several methods, like This paper proposes an improvement to a delayed signal cancellation based synchronization algorithm for unbalanced grids.
The proposed PLL structure employs only half of the delay required Full Text Available The control of power converter devices is one of the main research lines in interfaced renewable energy sources, such as solar cells and wind turbines. Various synchronisation techniques based control strategies are implemented for the hybrid power system applications under unbalanced conditions in literature studies. One of the most important aspects for the proper operation of the single-phase grid-tied power-conditioning systems is the synchronization with the utility grid.
Among various synchronization techniques, phase locked loop PLL based algorithms have found a lot of interest for the advantages The nanoparticle delivery system increases vaccine thermostability and immunogenicity compared to free vaccine. Vaccination by MN patch produces stronger immune responses than intramuscular administration.
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KGaA, Weinheim. MicroRNA miR inhibition is a promising biological strategy for breast cancer therapy. However its application is limited by the lack of efficient miRNA inhibitor delivery systems.
As a cationic polymer transfection material for nucleic acids, the poly l-lysine -modified polyethylenimine PEI- PLL copolymer combines the high transfection efficiency of polyethylenimine PEI and the good biodegradability of polyllysine PLL. The miR expression and the cellular physiology were determined post transfection. The results indicated that the miR inhibition could induce the cell cycle arrest in G1 phase, upregulate the expression of Programmed Cell Death Protein 4 PDCD4 and thus active the caspase-3 apoptosis pathway.
This work was a combination of the high transfection efficiency of polyethylenimine PEI , the good biodegradability of polyllysine PLL and the breast cancer-killing effect of miR inhibitors. The nanoparticle cytotoxicity was evaluated in vitro using rat cortical neurons. Brain edema was assessed using the brain edema ratio, and the antioxidative activity was assessed by measuring the superoxide dismutase SOD activity and the malondialdehyde MDA content in the brain tissue.
Adaptive hysteresis band current control AHB CC is used to control the three-phase grid currents by means of grid side converter in wind power generation system in this paper. First the mathematical models of each part are given The simulation results have verified that the control strategy is feasible to fit for control of gird currents, active power, reactive power and DC-link voltage in wind power generation system Virtual flux oriented direct power control VFDPC is combined space vector modulation SVM with PI of DC-link voltage, active power and reactive power to control the grid side converter in wind power generation system in this paper.
The simulation results have verified that the control strategy is feasible to fit for control of gird currents, active power, reactive power and DC-link voltage An improved phase-locked loop method for automatic resonance frequency tracing based on static capacitance broadband compensation for a high-power ultrasonic transducer. The phase-locked loop PLL method is widely used for automatic resonance frequency tracing ARFT of high-power ultrasonic transducers, which are usually vibrating systems with high mechanical quality factor Qm.
However, a heavily-loaded transducer usually has a low Qm because the load has a large mechanical loss. In this paper, a series of theoretical analyses is carried out to detail why the traditional PLL method could cause serious frequency tracing problems, including loss of lock, antiresonance frequency tracing, and large tracing errors. Experiments using a generator based on the novel method were carried out using crude oil as the transducer load.
From frequency to time-average- frequency a paradigm shift in the design of electronic system. Written in a simple, easy to understand style, this book will teach PLL users how to use new clock technology in their work in order to create innovative applications. On the basis of the established impedance modeling of the DFIG system, it is found that the PLL with fast control dynamics may result in the occurrence of MFR due to a decreasing phase margin.
The simulation The MPPT strategy used consists of two levels, the first level is a power regulation loop and the second level is an extremum seeking bloc generating the coefficient gathering the turbine characteristics. Figures illustrating the estimated speed and angle confirm that the SRF- PLL is able to give an estimated speed and angle which closely follow the real ones. Also, the power at the DC load and the power at the generator output indicate that the MPPT gives optimum extracted power.
Finally, other results show the effectiveness of the adopted approach in real time applications. Stability of small-amplitude periodic solutions near Hopf bifurcations in time-delayed fully-connected PLL networks. In this paper we investigate stability conditions for small-amplitude periodic solutions emerging near symmetry-preserving Hopf bifurcations in a time-delayed fully-connected N-node PLL network. The study of this type of systems which includes the time delay between connections has attracted much attention among researchers mainly because the delayed coupling between nodes emerges almost naturally in mathematical modeling in many areas of science such as neurobiology, population dynamics, physiology and engineering.
In a previous work it has been shown that symmetry breaking and symmetry preserving Hopf bifurcations can emerge in the parameter space.