Ancient Egyptian Influence on Modern Religion Essay

Egypt is considered the birthplace of many world religions. It contains some of the oldest religious artifacts, texts, and art that can be traced to modern religions. Signs of early Egyptian religion date back to the Predynastic period, beginning with evidence of polytheistic worship. Many scholars have researched the development of Ancient Egyptian religion over the centuries and have studied the direct correlation between it and the modern religions of Judaism and Christianity. Questions arise as to whe Judaism developed because of social and political conditions of Ancient Egypt or rather through conscious adaptation of Egyptian stories, values, and traditions. Was it through divine inspiration that the faiths formed, or was it simply†¦show more content†¦Ptah was also a creator god who built the boats that carried the souls of the dead into the Underworld. Osiris was the ruler of the Underworld and husband to Isis, the goddess of fertility and the ideal wife. Isis†™ song, Horus, was the god of the sky and depicted with a hawk-like head often portrayed with a double crown. These deities were worshipped daily by the Egyptians in temples built by the ruling pharaoh and his priests. The pharaoh was viewed as the intermediary between the deities and his people. Through his kingship and divine power, he was expected to maintain universal peace and order. Egyptians also underwent extensive and excessive processes to preserve their souls after death through tombs, mummification, and offerings to the gods for preservation of the deceased bodies (â€Å"Ancient Egyptian Religion†). The concept of life after death is rooted in ancient Egyptian religion where funerary processes and burial rituals were fundamental and crucial to an afterlife. Egypt was one of the first countries to convert to Christianity in 43 A.D. From the persecution of Christ by the Romans to the acceptance of Christianity as the imperial religion of the empire, Christia nity underwent significant changes in the first few centuries after Christ’s ascension. Many Egyptian pagan beliefs and deity legends were unconsciously transferred to infant Christian faith and reformed in stories of the new deity, Jesus. Several elementsShow MoreRelatedEgyptian Religion s Influence Over Christianity1588 Words   |  7 PagesEgyptian Religion’s Influence Over Christianity Religion is present in almost every single culture in the world and has been for several thousands of years. Egypt is one of the first known and recorded civilizations in the world and has been studied for as long as its artifacts have been founded. In the discoveries of these artifacts, historians have found religious-like stories with Gods and supernatural elements. 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Vlsi design and embedded systems - Free Essay Example

Sample details Pages: 21 Words: 6255 Downloads: 4 Date added: 2017/06/26 Category Statistics Essay Did you like this example? CHAPTER 1 INTRODUCTION 1.1 Motivation Phase locked loop (PLL) [1-3] is the heart of the many modern electronics as well as communication system. Recently plenty of the researches have conducted on the design of phase locked loop (PLL) circuit and still research is going on this topic. Most of the researches have conducted to realize a higher lock range PLL with lesser lock time [4] and have tolerable phase noise. Don’t waste time! Our writers will create an original "Vlsi design and embedded systems" essay for you Create order The most versatile application of the phase locked loops (PLL) is for clock generation and clock recovery in microprocessor, networking, communication systems, and frequency synthesizers. Phase locked-loops (PLLs) are commonly used to generate well-timed on-chip clocks in high-performance digital systems. Modern wireless communication systems employ Phase Locked Loop (PLL) mainly for synchronization, clock synthesis, skew and jitter reduction [5]. Phase locked loops find wide application in several modern applications mostly in advance communication and instrumentation systems. PLL being a mixed signal circuit involves design challenge at high frequency. Since its inspection in early 1930s, where it was used in the synchronization of the horizontal and vertical scans of television, it has come to an advanced form of integrated circuit (IC). Today found uses in many other applications. The first PLL ICs were available around 1965; it was built using purely analog component. Recent advances in integrated circuit design techniques have led to the development of high performance PLL which has become more economical and reliable. Now a whole PLL circuit can be integrated as a part of a larger circuit on a single chip. There are mainly five blocks in a PLL. These are phase frequency detector (PFD), charge pump (CP), low pass loop filter (LPF), voltage controlled oscillator (VCO) and frequency divider. Presently almost all communication and electronics devices operate at a higher frequency, so for that purpose we need a faster locking PLL. So there are a lot of challenges in designing the mentioned different blocks of the PLL to operate at a higher frequency. And these challenges motivated me towards this research topic. In this work mainly the faster locking of the PLL is concentrated by properly choosing the circuit architectures and parameters. The optimization of the VCO circuit is also carried out in this work to get a better frequency precision. 1.2 Organization of Thesis Before going into the details of the PLL, the motivation behind this work is mentioned in the Chapter 1 of the thesis. Chapter 2 briefly describes the whole PLL system. An introduction to the PLL circuit is mentioned in the section 2.1. Section 2.2 contains the detail architecture of the whole PLL system. Different types of PLLs are mentioned in the section 2.3. Section 2.4 explains the basic terms used in the PLL system while the consecutive sections give the details about the noise and application of the PLL. Chapter 3 builds the concepts of optimization. Definition of optimization technique and different circuit optimization techniques are presented in section 3.1 and 3.2 respectively. Section 3.3 gives the brief outline of the concept of geometric programming and convex optimization. The optimization of the CSVCO circuit is explained in section 3.4. The design and synthesis of the PLL is described in Chapter 4. The different design environments used in this work is mentioned in the section 4.1. The adopted design procedure is explained in section 4.2. Section 4.3 gives the design specifications and parameters of the work. The simulation results of the different circuits used in the PLL are depicted in the different sections of the Chapter 5. The performance of the CSVCO designed using convex optimization is compared with that of the traditional method in section 5.3. Section 5.5 gives the different simulation results of the PLL and its performance comparison between schematic and post layout level. At last Chapter 6 provides the conclusion that inferred from the work. CHAPTER 2 PHASE LOCKED LOOP 2.1 Introduction A PLL is a closed-loop feedback system that sets fixed phase relationship between its output clock phase and the phase of a reference clock. A PLL is capable of tracking the phase changes that falls in this bandwidth of the PLL. A PLL also multiplies a low-frequency reference clock CKref to produce a high-frequency clock CKout this is known as clock synthesis. A PLL has a negative feedback control system circuit. The main objective of a PLL is to generate a signal in which the phase is the same as the phase of a reference signal. This is achieved after many iterations of comparison of the reference and feedback signals. In this lock mode the phase of the reference and feedback signal is zero. After this, the PLL continues to compare the two signals but since they are in lock mode, the PLL output is constant. The basic block diagram of the PLL is shown in the Figure 2.1. In general a PLL consists of five main blocks: Phase Detector or Phase Frequency Detector (PD or PFD) Charge Pump (CP) Low Pass Filter (LPF) Voltage Controlled Oscillator (VCO) Divide by N Counter The Phase frequency Detector (PFD) is one of the main parts in PLL circuits. It compares the phase and frequency difference between the reference clock and the feedback clock. Depending upon the phase and frequency deviation, it generates two output signals UP and DOWN. The Charge Pump (CP) circuit is used in the PLL to combine both the outputs of the PFD and give a single output. The output of the CP circuit is fed to a Low Pass Filter (LPF) to generate a DC control voltage. The phase and frequency of the Voltage Controlled Oscillator (VCO) output depends on the generated DC control voltage. If the PFD generates an UP signal, the error voltage at the output of LPF increases which in turn increase the VCO output signal frequency. On the contrary, if a DOWN signal is generated, the VCO output signal frequency decreases. The output of the VCO is then fed back to the PFD in order to recalculate the phase difference, and then we can create closed loop frequency control system. 2.2 PLL Architecture The architecture of a charge-pump PLL is shown in Figure 2.2. A PLL comprises of several components. They are (1) phase or phase frequency detector, (2) charge pump, (3) loop filter, (4) voltage-controlled oscillator, and (5) frequency divider. The functioning of each block is briefly explained below. 2.2.1 PhaseFrequency Detector The Phase frequency Detector (PFD) is one of the main part in PLL circuits. It compares the phase and frequency difference between the reference clock and the feedback clock. Depending upon the phase and frequency deviation, it generates two output signals UP and DOWN. Figure 2.3 shows a traditional PFD circuit. If there is a phase difference between the two signals, it will generate UP or DOWN synchronized signals. When the reference clock rising edge leads the feedback input clock rising edge UP signal goes high while keeping DOWN signal low. On the other hand if the feedback input clock rising edge leads the reference clock rising edge DOWN signal goes high and UP signal goes low. Fast phase and frequency acquisition PFDs [6-7] are generally preferred over traditional PFD. 2.2.2ChargePump and Loop Filter Charge pump circuit is an important block of the whole PLL system. It converts the phase or frequency difference information into a voltage, used to tune the VCO. Charge pump circuit is used to combine both the outputs of the PFD and give a single output which is fed to the input of the filter. Charge pump circuit gives a constant current of value IPDI which should be insensitive to the supply voltage variation [8]. The amplitude of the current always remains same but the polarity changes which depend on the value of the UP and DOWN signal. The schematic diagram of the charge pump circuit with loop filter is shown in the Figure 2.4. When the UP signal goes high M2 transistor turns ON while M1 is OFF and the output current is IPDI with a positive polarity. When the down signal becomes high M1 transistor turns ON while M2 is OFF and the output current is IPDI with a negative polarity. The charge pump output current [3] is given by IPDI=IPUMPIPUMP4 =2IPUMP4 =IPUMP2 =KPDI (1) Where KPDI=IPUMP2 (amps/radian) (2) The passive low pass loop filter is used to convert back the charge pump current into the voltage. The filter should be as compact as possible [9].The output voltage of the loop filter controls the oscillation frequency of the VCO. The loop filter voltage will increase if Fref rising edge leads Fin rising edge and will decrease if Fin rising edge leads Fref rising edge. If the PLL is in locked state it maintains a constant value. The VCO input voltage is given by Vinvco = KF IPDI (3) Where KF is the gain of the loop filter. 2.2.3Voltage ControlledOscillator An oscillator is an autonomous system which generates a periodic output without any input. The most popular type of the VCO circuit is the current starved voltage controlled oscillator (CSVCO). Here the number of inverter stages is fixed with 5. The simplified view of a single stage current starved oscillator is shown in the Figure 2.5. Transistors M2 and M3 operate as an inverter while M1 and M4 operate as current sources. The current sources, Ml and M4, limit the current available to the inverter, M2 and M3; in other words, the inverter is starved for current. The desired center frequency of the designed circuit is 1GHz with a supply of 1.8V. The CSVCO is designed both in usual manner as mentioned in [3], [10, 11]. The general circuit diagram of the current starved voltage controlled oscillator is shown in the Figure 2.6. To determine the design equations for the CSVCO, consider the simplified view of VCO in Figure 2.5. The total capacitance on the drains of M2 and M3 is given by Ctot=52Cox(LpWp+LnWn) (4) The time it takes to charge Ctot from zero to VSP with the constant current ID4 is given by t1=VSPID4Ctot (5) While the time it takes to discharge Ctot from VDD to VSP is given by t1=VDD-VSPID1Ctot (6) If we set ID4= ID1=ID then the sum of t1 and t2 is given by t1+t2=VDDIDCtot (7) The oscillation frequency of CSVCO for N number of stage is fosc=1Nt1+t2=IDNCtotVDD (8) This is equal to fcenter when Vinvco=VDD2 (9) The gain of the VCO is given by KVCO=fmax-fminVmax-Vmin HzV (10) 2.2.4 FrequencyDivider The output of the VCO is fed back to the input of PFD through the frequency divider circuit. The frequency divider in the PLL circuit forms a closed loop. It scales down the frequency of the VCO output signal. A simple D flip flop (DFF) acts as a frequency divider circuit. The schematic of a simple DFF based divide by 2 frequency divider circuit is shown in the Figure 2.7. 2.3 Types of PLL There are mainly 4 types of PLL are available. They are . Liner PLL Digital PLL All Digital PLL Soft PLL 2.4 Terms in PLL 2.4.1 Lock in Range Once the PLL is in lock state what is the range of frequencies for which it can keep itself locked is called as lock in range. This is also called as tracking range or holding range. 2.4.2 Capture Range When the PLL is initially not in lock, what frequency range can make PLL lock is called as capture range. This is also known as acquisition range. This is directly proportional to the LPF bandwidth. Reduction in the loop filter bandwidth thus improves the rejection of the out of band signals, but at the same time the capture range decreases, pull in time becomes larger and phase margin becomes poor. 2.4.3 Pull in Time The total time taken by the PLL to capture the signal (or to establish the lock) is called as Pull in Time of PLL. It is also called as Acquisition Time of PLL. 2.4.4 Bandwidth of PLL Bandwidth is the frequency at which the PLL begins to lose the lock with reference. 2.5 Noises in PLL The output of the practical system deviates from the desired response. This is because of the imperfections and noises in the system. The supply noise also affects the output noise of the PLL system [12]. There are mainly 4 types of noises. They are explained below. 2.5.1 Phase Noise The phase fluctuation due to the random frequency variation of a signal is called as phase noise. This is mostly affected by oscillators frequency stability. The main sources of the phase noise in PLL are oscillator noise [12-15], PFD and frequency divider circuit. The main components of the phase noise are thermal and flicker noise. 2.5.2 Jitter A jitter is the short term-term variations of a signal with respect to its ideal position in time [16-19]. This problem negatively impacts the data transmission quality. Jitter and phase noise are closely related and can be computed one from another [18]. Deviation from the ideal position can occur on either leading edge or trailing edge of signal. Jitter may be induced and coupled onto a clock signal from several different sources and is not uniform over all frequencies. Excessive jitter can increase bit error rate (BER) of communication signal [19]. In digital system Jitter leads to violation in time margins, causing circuits to behave improperly. 2.5.3 Spur Non-desired frequency content not related to the frequency of oscillation and its harmonics is called as Spur. There are mainly two types of spur. They are reference spur and fractional spur. Reference spur comes into picture in an integer PLL while fractional spur plays a major role in fractional PLL. When the PLL is in lock state the phase and frequency inputs to the PFD are essentially equal. There should not be any error output from the PFD. Since this can create problem, so the PFD is designed such that, in the locked state the current pulses from the CP will have a very narrow width as shown in the Figure 2.9. Because of this the input control voltage of the VCO is modulated by the reference signal and thus produces Reference Spur [20]. 2.5.4 Charge Pump Leakage Current When the CP output from the synthesizer is programmed to the high impedance state, in practice there should not be any current flow. But in practical some leakage current flows in the circuit and this is known as charge pump leakage current [20]. 2.6 Applications of PLL The demand of the PLL circuit increases day by day because of its wide application in the area of electronics, communication and instrumentation. The recent applications of the PLL circuits are in memories, microprocessors, hard disk drive electronics, RF and wireless transceivers, clock recovery circuits on microcontroller boards and optical fiber receivers. Some of the PLL applications are mentioned below. 1.FrequencySynthesis A frequency synthesizer is an electronic system for generating a range of frequencies from a single fixed time base or oscillator. 2.Clock Generation Many electronic systems include processors of various sorts that operate at hundreds of megahertz. Typically, the clocks supplied to these processors come from clock generator PLLs, which multiply a lower-frequency reference clock (usually 50 or 100 MHz) up to the operating frequency of the processor. The multiplication factor can be quite large in cases where the operating frequency is multiple GHz and the reference crystal is just tens or hundreds of megahertz. 3.Carrier Recovery (Clock Recovery) Some data streams, especially high-speed serial data streams (such as the raw stream of data from the magnetic head of a disk drive), are sent without an accompanying clock. The receiver generates a clock from an approximate frequency reference, and then phase-aligns to the transitions in the data stream with a PLL. This process is referred to as clock recovery. 4. SkewReduction This is one of the very popular and earliest uses of PLL. Suppose synchronous pair of data and clock lines enter a large digital chip. Since clock typically drives a large number of transistors and logic interconnects, it is first applied to large buffer. Thus, the clock distributed on chip may suffer from substantial skew with respect to data. This is an undesirable effect which reduces the timing budget for on-chip operations. 5. Jitterand Noise Reduction One desirable property of all PLLs is that the reference and feedback clock edges be brought into very close alignment. The average difference in time between the phases of the two signals when the PLL has achieved lock is called the static phase offset. The variance between these phases is called tracking jitter. Ideally, the static phase offset should be zero, and the tracking jitter should be as low as possible. CHAPTER 3 CONVEX OPTIMIZATION OF VCO IN PLL 3.1 What is an optimization technique? Optimization technique is nothing but the finding of the action that optimizes i.e. minimizes or maximizes the result of the objective function. Optimization technique is applied to the circuits aiming at finding out the optimized circuit design parameter to achieve either the best performance or the desired performance. Optimization techniques are a set of most powerful tools that are used in efficiently handling the design resources and there by achieve the best result. Mainly optimization techniques are applied to the circuit for the selection of the component values, devices sizes, and value of the voltage or current source. 3.2 Types of circuit optimization method There are mainly four types of circuit optimization methods exist. They are Classical optimization Knowledge based optimization Global optimization method Convex optimization and geometric programming 3.2.1 Classical Optimization Methods: In case of analog circuit CAD, classical optimization methods [21], such as steepest descent, sequential quadratic programming, and Lagrange multiplier methods are mainly used. These methods are used with more complicated circuit models, including even full SPICE simulations in each iteration. This method can handle a wide variety of problem. For this there is a need of a set of performance measures and computation of one or more derivatives. The main disadvantage of the classical optimization methods is that the global optimal solution is not possible. This method fails to find a feasible design even one exist. This method gives only the local minima instead of global solution. Since many different initial designs are considered to get the global optimization, the method becomes slower. Because of the human intervention (to give good initial designs), the method becomes less automated. The classical methods become slow if complex models are used. 3.2.2 Knowledge-Based Methods: Knowledge-based and expert-systems methods such as genetic algorithm or evolution systems, systems based on Fuzzy logic, and heuristics-based systems have also been widely used in analog circuit CAD [21]. In case of knowledge based methods, there are few limitations on the types of problems, specifications, and performance measures that are to be considered. These methods do not require the computation of the derivatives. This is not possible to find a global optimal design solution using these methods. The final design is decided on the basis of the initial design chosen and the algorithm parameters. The disadvantage of the knowledge based methods is that they simply fail to find a feasible solution even when one may exist. There is a need of human intervention during the design and the training process. 3.2.3 Global Optimization Methods: Global optimization methods such as branch and bound and simulated annealing are also used in analog circuit design [21]. These methods are guaranteed to find the global optimal design solution. The global optimal design is determined by the branch and bound methods unambiguously. In each iteration, a suboptimal feasible design and also a lower bound on the achievable performance is maintained by this method. This enables the algorithm to terminate non-heuristically, i.e., with complete confidence that the global design has been found within a given tolerance. The branch and bound method is extremely slow, with computation growing exponentially with problem size. The trapping in a locally optimal design can be avoided by using simulated annealing (SA). This method can compute the global optimal solution but not guaranteed. Since there is no real-time lower bound is available, so termination is heuristic. This method can also handle a wide variety of performance indices and objects. T he main advantage of SA is that it handles the continuous variables and discrete variables problems efficiently and reduces the chances of getting a non-globally optimal design. The only problem with this method is that it is very slow and can not guarantee a global optimal solution. 3.2.4 Convex Optimization and Geometric Programming Methods: Geometric programming methods are special optimization problems in which the objective and constraint functions are all convex [22-24]. Convex optimization technique can solve the problems having a large number of variables and constraints very efficiently [22]. The main advantage of this method for which people generally adopt is that the method gives the global solution. Infeasibility is unambiguously detected. Since a lower bound on the achievable performance is given, so the method uses a completely non- heuristic stopping criterion. 3.3 Geometric programming and convex optimization Geometric programming is a special type of optimization technique in which all the objective must be convex. Before applying this technique it has to confirm that whether the given problem is convex optimization problem or not. Convex optimization problem means the problem of minimizing a convex function subject to convex inequality constraints and linear equality constraints. In IC integration convex optimization and geometric programming has become a more efficient computational tool for optimization purpose. This method has an ability to handle thousands of variables and constraints and solve efficiently. The main advantage of convex optimization technique is that it gives the global optimized value and the robust design. The fact that geometric programs can be solved very efficiently has a number of practical consequences. For example, the method can be used to simultaneously optimize the design of a large number of circuits in a single large mixed-mode integrated circuit. The de signs of the individual circuits are coupled by constraints on total power and area, and by various parameters that affect the circuit coupling such as input capacitance, output resistance, etc. Convex optimization is used to find out the optimized value of these parameter and sizing of the devices in the circuit [25]. Another application is to use the efficiency to obtain robust designs i.e., designs that are guaranteed to meet a set of specifications over a variety of processes or technology parameter values. This is done by simply replicating the specifications with a (possibly large) number of representative process parameters, which is practical only because geometric programs with thousands of constraints are readily solved. A real valued function fx defined on an interval (space) is called convex if ftx1+1-tx2tfx1+1-tfx2 (11) For every t,0t1 and x1x2 In the Figure 3.1 function fx is represented as a convex function on an interval. The convex optimization problem is in the form of minimize f0x Subjected to fix1 , i=1, 2, 3, m gix=1 , i=1, 2, 3, p xi1 , i=1, 2, 3, n Where fix is a posynomial function gix is a monomial function Let x1,x2xn be n real positive variables. We can denote the vector (xi,xi.xi) of these variables asx. A function f is called a posynomial function of x if it has the form fix1,x2xn=k=1tCkx11kx22k..xnnk (12) Where Cj0 and ij R. The coefficients Cj must be nonnegative but the exponents ij can be any real numbers including negative or fractional. When there is exactly one nonzero term in the sum i.e. t=1 and C10, we call f is a monomial function. 3.3.1 Advantages: Handle thousands of variables and constraints and solve efficiently. Global optimization can be obtained. 3.3.2 Disadvantages: * Strictly limited to types of problems, performance specification and objectives that can be handled. 3.4 Optimization of the VCO circuit In my earlier design of the VCO circuit, the sizes of all the five inverter stages are same. Now the convex optimization technique is applied to find out the optimal scaling ratio of the different inverter stages to get the optimal design with a better performance. There are 5 inverter stages and the design has to give a delay of 100ps. The load capacitance of the VCO circuit is 65 fF. All these design constraints are formulated and applied to the convex optimization technique. Mainly optimization techniques are applied for selection of component values and transistor sizing. In this work I have used the geometric programming technique to find out the optimized scaling ratio of the different stages in CSVCO to meet the desired center frequency with lesser deviation. Let xi is the scaling ration of the ith stage, CL is the load capacitance, and D is the total delay of the inverter stages then optimization problem is in the form of Minimize sum (xi) Subjected to CLCLmax DDmax Where CLmax and Dmax are required design parameters and has a constant value. CHAPTER 4 DESIGN AND SYNTHESIS OF PLL 4.1 Design Environment The schematic level design entry of the circuits is carried out in the CADENCE Virtuoso Analog Design Environment. The layout of the PLL is designed in Virtuoso XL using GPDK090 library. In order to analyze the performances, these circuits are simulated in the Spectre simulator of CADENCE tool. Different performance indices such as phase noise, power consumption and lock time are measured in this environment. Transient, parametric sweep and phase noise analyses are carried out in this work to find out the performances of the circuit. The optimization of the current starved VCO circuit, the scale factor for transistor sizing is found out using the MATLAB environment. 4.2 Design Procedure 4.2.1 VCO Design Since VCO is the heart of the whole PLL system, it should be designed in a proper manner. The design steps for the current starved VCO are as follows. Step 1 Find the value of the propagation delay for each stage of the inverter in the VCO circuit using the following equation. p=1Nf (13) Where p= phl= plh= half of the propagation delay time of the inverter N= no of inverter stages f= required center frequency of oscillation Step 2 Find the WL ratio for the transistors in the different inverter stages using the equation in below. WL n=CloadphlnCoxVdd-VT,n2VT,nVdd-VT,n+ln4Vdd-VT,nVdd-1 (14) WL p=CloadplhpCoxVdd-VT,p2VT,pVdd-VT,p+ln4Vdd-VT,pVdd-1 (15) Step 3 After finding the WL ratio, find the values for W and L. Step 4 Find the value of the total capacitance form the expression Ctot=52Cox(LpWp+LnWn) (16) Where Cox is the oxide capacitance Lp,Wp,Ln,Wn is the width and length of the PMOS and NMOS transistors in the inverter stages. Step 5 Calculate the value of drain current for the center frequency which is given by IDcenter=NCtotVddf (17) Step 6 Find the WL ratio for the current starving transistors in the circuit from the drain current expression which is represented as WL n=2IDcenternCoxVgs-VT,n2 (18) Similarly WL p=2.5WL n (19) 4.2.2 Design of Phase Locked Loop The value of the charge pump current and the component parameters of the loop filter play a major role in the design of the phase locked loop circuit. The value of the lock time mainly depends upon these parameters. So while designing the circuit proper care should be taken in calculating these parameters. For the given values of reference(Fref) and output frequency(Fout) as well as the lock in range, the following steps to be carried out in designing the filter circuit. Step 1 Find the value of the divider circuit to be used which is given by n=FoutFref (20) Step 2 Find the value of the natural frequency (n) from the lock in range as given below lock in range=2n (21) Step 3 Find the value of the charge pump gain (KPDI) from the charge pump current used in the circuit which is given by KPDI=Ipump2 (Amps/radian) (22) Step 4 Find the value of the gain of the VCO (Kvco) circuit from the characteristics curve using the following expression. Kvco=fmax-fminVmax-Vmin (Hz/V) (23) Step 5 Find the values of the loop filter component parameters using the following expressions. C1=KPDIKvcoNn2 (24) C2=C110 (25) R=2nC1 (26) 4.3 Design Specifications and Parameters 4.3.1 VCO Design Specification The current starved VCO design specifications are mentioned in the following table. Parameter Value Center frequency 1GHz No. of inverter stage 5 Inverter delay 100ps Load capacitance 65fF Supply voltage 1.8V Table 1 VCO design specifications 4.3.2 VCO Design Parameters Parameter Value Width of Current starved PMOS(WPCS) 2.33m Width of Current Starved NMOS(WnCS) 140nm Width of PMOS in Inverter(WP) 2.44m Width of NMOS in Inverter(Wn) 150nm LPCS = LnCS = LP = Ln = L 100nm Table 2 List of design parameters of the CSVCO circuit 4.3.3 PLL Design Parameters The whole PLL system design specifications and parameters are shown in the Table 3. Parameter Value Reference frequency((Fref) 500 MHz output frequency(Fout) 1 GHz Lock in range 100 MHz Supply voltage 1.8 V Divider circuit By 2 Charge pump current(Ipump) 600 A Capacitor (C1) 15 pF Capacitor (C2) 1.5 pF Resistor (R) 1.384 K Table 3 PLL design specifications and parameters CHAPTER 5 SIMULATION RESULT AND DISCUSSION 5.1 Phase Frequency Detector The Pass Transistor DFF PFD circuit is shown in Figure 5.1. The PFD is same as to a dynamic two-phase master-slave pass-transistor flip-flop. The clock skew is minimized by using single edge clocks. In this design synchronous reset is used for master while asynchronous reset is used for slave. i.e., the reset is allowed only when the slave latch is transparent. The operating range of the design is increased with the help of synchronous resetting and also the power consumption is reduced compared to the traditional PFD. If the master latch is reset while it is transparent, then there will be significant short-circuit current will produce, resulting in more power. The output of the PFD when Fref signal rising edge leads Fin signal rising edge and vice versa is shown in the Figure 5.2 and Figure 5.3 respectively. 5.2 Charge Pump and Loop Filter When the reference signal clock edge leads the feedback clock edge, the UP signal of the PFD goes high. So to make both the clock have rising edge at the same time the VCO output signal frequency has to be increased. For this purpose an increase in control voltage is needed from the output of charge pump and loop filter circuit. The simulation result which is shown in the Figure 5.4 below gives an increase in the control voltage at the output of the loop filter circuit. From the Figure 5.4 its clear that the control voltage increases for a period during which the UP signal of the PFD remains high. In the other case a decrease in the control voltage is produced at the output of the filter circuit which is shown in the Figure 5.5. When the rising of feedback signal leads the reference signal rising edge the control voltage decreases for the period during which the DOWN signal of the PFD remains high. 5.3 Voltage Controlled Oscillator 5.3.1 Result using traditional method The heart of the PLL circuit is the voltage controlled oscillator. The circuit is designed to give a center frequency of oscillation of 1 GHz. The frequency of oscillation of the output signal for the different input control voltage is mentioned in the Table 4. The center frequency of oscillation at an input control voltage of VDD/2 is 1.012 GHz. The output signal of the VCO at a control voltage of VDD/2 is shown in the Figure 5.6. Control Voltage (VC)(in volt) Frequency of Oscillation (f) (in MHz) 0.103 24.415 0.154 50.929 0.206 91.05 0.257 139.32 0.309 188.179 0.36 234.277 0.411 282.125 0.463 342.256 0.514 412.889 0.566 489.48 0.617 569.178 0.669 650.037 0.720 731.72 0.771 812.946 0.823 893.63 0.874 973.461 Control Voltage Frequency of Oscillation 0.926 1051.851 0.977 1128.02 1.03 1200.67 1.08 1271.818 1.13 1338.398 1.18 1401.32 1.23 1460.798 1.29 1517.121 1.34 1570.371 1.39 1620.798 1.44 1668.416 1.49 1713.913 1.54 1757.073 1.59 1798.081 1.65 1836.986 1.7 1873.865 1.75 1909.109 1.8 1943.021 Table 4 Oscillating frequency of the VCO output signal for different control voltage The VCO characteristics curve is shown in the Figure 5.7. The X-axis of the curve represents the input control voltage while the Y-axis represents the corresponding frequency of oscillation. The gain of the CSVCO circuit is 1.531 GHz/V. The phase noise of the VCO in the schematic level is found to be -82.87 dBc/Hz. The phase noise plot for schematic level is shown in the Figure 5.8. The layout of the 5 stage current starved VCO is shown in the Figure 5.9. The schematic and post layout level simulation results are compared in the Table 5. Parameter Schematic Result Post-Layout Result Frequency(f) 1.012 GHz 1.00256 GHz Frequency Deviation(f) 12 MHz 2.56 MHz Power(P) 432.456 W 480.63 W Phase Noise @1MHz offset -82.7 dBc/Hz -84.88 dBc/Hz Table 5 Comparison of schematic and post layout level simulation results 5.3.2 Result using convex optimization method Using convex optimization method the scaling ratio is found out to satisfy the center frequency of oscillation (i.e. delay of the circuit) from the MATLAB environment. The scaling ratio for different stages of the inverter in the VCO is 1,1,1,1 and 1.4058. The scaling ratio result is shown in the Figure 5.10. Now the transistor sizes are modified according to the scaling ratio. Since the scaling factor of all the stages are 1 except 5th stage, so the transistor sizing of the 5th stage has only changed to get the better frequency precision. The sizes of the transistors of CSVCO optimized using convex optimization technique are listed out in the Table 6. Before optimization the centre frequency of the oscillation is found out 1.012GHz. And after applying the convex optimization and geometric programming to this circuit, the centre frequency of oscillation is 1000.0457MHz. So the frequency deviation from its centre frequency is reduced to .00457% from 1.2%. The performance of CSVCO for both traditional and geometric programming is compared in the Table 7. The comparison of control voltage versus oscillating frequency characteristics of the CSVCO circuit is shown in the Figure 5.11. Stage Parameter value 1 WPCS WnCS WP Wn 2.33m 140nm 2.44m 150nm 2 WPCS WnCS WP Wn 2.33m 140nm 2.44m 150nm 3 WPCS WnCS WP Wn 2.33m 140nm 2.44m 150nm 4 WPCS WnCS WP Wn 2.33m 140nm 2.44m 150nm 5 WPCS WnCS WP Wn 3.28m 195nm 3.435m 215nm Table 6 Size of the transistors of CSVCO circuit after optimization Factor CSVCO using traditional method CSVCO using convex optimization method Frequency(f) 1.012GHz 1.0000457GHz Frequency Deviation(f) 12MHz 45.7KHz Power(P) 432.456W 539.65W Phase Noise @1MHz offset -82.7 dBc/Hz -82.6 dBc/Hz KVCO 1.531GHz/V 1.5926GHz/V Table 7 Performance comparison of CSVCO designed using traditional method and convex optimization 5.4 Frequency Divider The circuit diagram of a pass transistor based DFF frequency divider circuit is shown in the Figure 5.12. The circuit divides the frequency by a factor of 2. The simulation result of the divide by 2 circuits is shown in the Figure 5.13 5.5 Phase Locked Loop The output of the charge pump and loop filter circuit i.e. the control voltage will maintain a constant value when the references signal and feedback signal are in lock. The control voltage of PLL for the schematic level is shown in the Figure 5.14. From the Figure 5.14 its clear that the control maintains the constant value of 0.9 V at time 280.6 ns. So the lock time of PLL is 280.6 ns. The layout of the PLL is shown in the Figure 5.15. The most of the area of the PLL is consumed by the resistor and capacitor used in the filter network. Different signals like UP, DOWN, Control Voltage, reference signal and feedback input signal of the PLL in the lock state are shown in the Figure 5.16 and Figure 5.17 for schematic level and post layout level respectively. From the Figure 5.16 and 5.17 its clear that when the control voltage is constant, the reference signal and the feedback input signal are almost similar as their phase and frequency are approximately same. The phase noise analysis of the PLL is carried out both in the schematic as well as in the post layout level. The phase noise is found to be -86.21 dBc/Hz and -101.7 dBc/Hz in schematic and post layout level respectively. The phase noise variation of the PLL both in schematic and post layout level simulation are shown in the Figure 5.18 and 5.19 respectively. The performance comparison of the PLL both in schematic and post layout level simulation are mentioned in the Table 8. Parameter Result of Schematic Level Simulation Result of Post Layout Level Simulation Technology 90 nm 90 nm VDD 1.8 V 1.8 V Lock Time 280.6 ns 345.5 ns Frequency 1 GHz 1 GHz Maximum Power Consumption 11.9 mW 10.408 mW Phase Noise @ 1MHz offset -86.21 dBc/Hz -101.7 dBc/Hz Table 8 Performance comparison of PLL circuit CHAPTER 6 CONCLUSION AND FUTURE WORK In this work a PLL with a better lock time is presented. The lock time of the PLL is found to be 280.6 ns. The PLL circuit consumes a power of 11.9 mW from a 1.8 V D.C. supply The lock time of the PLL mainly depends upon the type of PFD architecture used and the parameters of the charge pump and loop filter. So by properly choosing the PFD architecture and adjusting the charge pump current and the loop filter component values a better lock time can be achieved. The centre frequency of oscillation of the VCO depends upon the sizing of the transistors. The frequency deviation from the desired value can be reduced by properly choosing the transistor sizes. By applying the convex optimization technique with frequency of oscillation as the main objective function, the deviation of oscillation frequency is minimized to 0.00457% from 1.2%. Here the convex technique to find out the transistor sizing to meet only the desired frequency specification. The other constraints like area, power and phase noise can also be applied.

Jekyll and Hyde Essay Introduction and Para 1 Free Essays

I am going to write an essay on Robert Louis Stevenson’s supernatural story, the strange case of Dr Jekyll and Mr Hyde, which was the inspiration for lots of modern movies showing dual nature of mankind e. g. The Hulk, Two Face and The Nutty Professor to name a few. We will write a custom essay sample on Jekyll and Hyde Essay Introduction and Para 1 or any similar topic only for you Order Now The story is told mostly in third person by Mr Utterson the lawyer, it is about the scientist Dr Jekyll and his â€Å"friend†, the hated Mr Hyde. Utterson suspects that Hyde may be bribing Jekyll when Jekyll changes his will to one where in the event of his death all his money and his house will be given to Hyde. However when Hyde disappears after brutally murdering the highly respected Sir Danvers Carew, Utterson is pleased, but when Jekyll starts acting weird and will not leave the confines of his cabinet Utterson becomes worried and after Jekyll becomes a recluse and starts making strange demands in a voice that is not his own, Jekyll’s butler and Utterson break down the doctor’s door to find Hyde lying dead on the floor from apparent suicide. The story is later explained in the novella through the testimony of Dr Lanyon, in which he reveals that he witnessed a transformation of Hyde to Jekyll and then explained in more detail by Jekyll. It turns out that Hyde was the result of one of Dr Jekyll’s experiments, where by drinking the ‘transforming draught’ he becomes the hated character who was the complete opposite of his usual self. Over time Jekyll found himself transforming without even drinking the potion, and when the drug ran out he became trapped as Hyde. Upon drinking the very last of the drug Jekyll writes, ‘I bring the life of that unhappy Henry Jekyll to an end’. I thought this book was very interesting and would recommend it to all. This novel is all about the dual nature of mankind. Stevenson believed that every person had a good and bad side to them. The book says a lot about Victorian society as they were all meant to be very good people but really lots of them were corrupt inside. The characters inside this novel show his theory about this very well. For example Jekyll is a well respected man, who was ‘born to a large fortune’ and ‘fond of respect of the wise and good among my fellow men†¦ with every guarantee of an honourable and distinguished future’. Like most people in Victorian society Dr Jekyll was obsessed with respect and he also had an evil side to him. He hated doing â€Å"evil† things such as gambling and drinking so much that he decided to make a potion to split his personality in two. When he first became Hyde, the evil side of his personality he felt ‘younger, lighter and happier in body’ which is because his evil side would not be as developed as his good side as he has done more good than evil in his life. He enjoyed being Hyde because he could do evil things without consequence or people finding out, or so he thought. He felt he did not need to feel guilty about the things he had done as they technically weren’t him. How to cite Jekyll and Hyde Essay Introduction and Para 1, Essays

Kurt Cobain (820 words) Essay Example For Students

Kurt Cobain (820 words) Essay Kurt CobainFor our modern day hero we used the singer and songwriter Kurt Cobain from the band Nirvana. This punk Seattle band moved almost mainstream almost overnight. Nirvana caught on fast and changed rock and roll music forever and molded the music of the 90s, alternative. Cobain had an enormous amount of talent but unfortunately his life was cut short by a still controversial suicide in his Seattle home. On April 9, 1994, his body was discovered. He is a hero for many of todays troubled youth because his music influences how these troubled kids feel. They are able relate to Cobain and his music. Kurt Cobain was born in 1967. He lived with his sister and parents two hundred miles away from Seattle in the small logging town of Aberdine. His aunt, who helped him form his first band, introduced him to music at a very young age. His parents divorced when Kurt was only seven years old. Torn up by his parents divorce, he went to live with his mother in a trailer. After the divorce, Kur t was forced to look at his life in a different light. Kurt became extremely anti-social, had few friends, and was picked on in school because kids thought he was gay or weird. Kurt started writing poetry at the age of thirteen, and when he was 14, he received his first guitar. Throughout high school he was in many bands- Fecal Matter, Skid Row, Brown Cow, The Sellouts and Pencap Chew. He formed Nirvana during his senior year of high school with his friends Chris Novoselic and Dave Grohl who Kurt called ?the worlds best drummer.? Shortly after the band was formed, Kurt dropped out of high school, and his mother kicked him out of the house. Homeless, he lived under a bridge at the end of his street. It was here that he would spend time alone writing his own songs. From his parents divorce to his mother pushing him out of the house, Kurt had become even more alienated from other people and life. He was very detached. Kurt hated the music of big rock bands like the Sex Pistols, Rolling Stones and Aerosmith. He felt their lyrics were sexist and pointless with no meaning. Kurt was a very sensitive and emotional person, a characteristic that showed through all of his songs. Eventually he became so famous that he a cult following. The songs exemplified the kids world. In the song ?Dumb? Kurt sings, ?I think Im dumb? over and over again to show how his years of neglect from his peers at high school and his family made him feel as if he was to blame. Kids relate to his music because it portrays how the world was so cruel and how he and the kids were treated badly. He was responsible for the most creative rock music of the last decade. Kurt didnt have to hide behind face paint or wear tight clothes to grab attention as the other rock stars. He wore fla nnels and jeans, something that every other kid wore, and he wasnt ashamed by it. In one song ?Come As You Are? Kurt sings ?Come as you are as I want you to be.? He wanted to show the youth that they dont have to follow the crowd and do something someone else wants them to do to fit in. Every modern alternative song has a tint of ?Nirvanaism? in it. Just like bands that followed the Beatles, many groups that followed Cobain tried to sound or copy his same music pattern. In his music he didnt communicate in complete sentences or elaborate arguments. Instead his lyrics were a stream of conscious insights that inspired and appealed to the short attention span of his audience. We picked Kurt Cobain as a hero because he is different than the conventional hero who just goes out and saves lives. Kurt was an emotional leader for the troubled youth, and he gave them a place to escape from a life that was hard to live. His music gave them a hideaway from the harsh realities of the real world. All they had to do was listen, and they felt instant relief because they knew that not only they felt the way they did. They could relate to Kurt and his fragile emotions. In the song ?Rape Me? Kurt sings; ?Rape me, my friend. Rape me again. Im not the only one. Hate me. Do it and do it again. Waste me. Taste me, my friend. My favorite inside source, Ill kiss your open sores. Appreciate your concern. Youll always stink and burn.? This shows how he believed society took advantage of him because he was weak and emotional. These kids relate to Kurt. Kurt once said that he would rather be in pain than fame. His words and music make him a modern day hero. .ua8f7a3d3d91ff22d487105490d1dc276 , .ua8f7a3d3d91ff22d487105490d1dc276 .postImageUrl , .ua8f7a3d3d91ff22d487105490d1dc276 .centered-text-area { min-height: 80px; position: relative; } .ua8f7a3d3d91ff22d487105490d1dc276 , .ua8f7a3d3d91ff22d487105490d1dc276:hover , .ua8f7a3d3d91ff22d487105490d1dc276:visited , .ua8f7a3d3d91ff22d487105490d1dc276:active { border:0!important; } .ua8f7a3d3d91ff22d487105490d1dc276 .clearfix:after { content: ""; display: table; clear: both; } .ua8f7a3d3d91ff22d487105490d1dc276 { display: block; transition: background-color 250ms; webkit-transition: background-color 250ms; width: 100%; opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #95A5A6; } .ua8f7a3d3d91ff22d487105490d1dc276:active , .ua8f7a3d3d91ff22d487105490d1dc276:hover { opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #2C3E50; } .ua8f7a3d3d91ff22d487105490d1dc276 .centered-text-area { width: 100%; position: relative ; } .ua8f7a3d3d91ff22d487105490d1dc276 .ctaText { border-bottom: 0 solid #fff; color: #2980B9; font-size: 16px; font-weight: bold; margin: 0; padding: 0; text-decoration: underline; } .ua8f7a3d3d91ff22d487105490d1dc276 .postTitle { color: #FFFFFF; font-size: 16px; font-weight: 600; margin: 0; padding: 0; width: 100%; } .ua8f7a3d3d91ff22d487105490d1dc276 .ctaButton { background-color: #7F8C8D!important; color: #2980B9; border: none; border-radius: 3px; box-shadow: none; font-size: 14px; font-weight: bold; line-height: 26px; moz-border-radius: 3px; text-align: center; text-decoration: none; text-shadow: none; width: 80px; min-height: 80px; background: url(https://artscolumbia.org/wp-content/plugins/intelly-related-posts/assets/images/simple-arrow.png)no-repeat; position: absolute; right: 0; top: 0; } .ua8f7a3d3d91ff22d487105490d1dc276:hover .ctaButton { background-color: #34495E!important; } .ua8f7a3d3d91ff22d487105490d1dc276 .centered-text { display: table; height: 80px; padding-left : 18px; top: 0; } .ua8f7a3d3d91ff22d487105490d1dc276 .ua8f7a3d3d91ff22d487105490d1dc276-content { display: table-cell; margin: 0; padding: 0; padding-right: 108px; position: relative; vertical-align: middle; width: 100%; } .ua8f7a3d3d91ff22d487105490d1dc276:after { content: ""; display: block; clear: both; } READ: Reflection on Mentorships EssayMusic Essays