Comparing the Fall of Han China and Roman Empire Essay Example for Free

Comparing the Fall of Han China and Roman Empire Essay Han China and Rome were two of the most powerful and popular empires of their time, but they fell like any other empire before them. Han China and Rome’s Empires had the same causes for their declines, but their effects are different. The major reasons for the fall of Rome are truly those that have to do with Romes political and economic state. One of the Rome’s problems prior to its fall was the lack of respect for authority, among the citizens and military forces. All the attacks from the barbarians caused problems in the military. This basically led to a lot of political turmoil because of all the chaos that was born, and it started to make the military crumble as well. Romes economy started to go downhill too, after a long period of time, especially because of the gold. The Romans started using gold (coins) and because of that the trade shortage of the eastern regions of the Empire served to block the growth of wealth in the west. The major reasons for Han China Empire’s fall were also because of their economic and political problems, but the effects are different. One of Han China’s problems was the uprising of desperate and hungry peasants. Another problem was their lack of authority to the Han government, which caused the economic problem. The Han Empire was being invaded by nomads, which were also known as barbarians. These barbarians kept invading the empire and made them have to keep fighting, and provide military forces. This worsened the economy and Han finances. Han government had to hire foreign soldiers who only wanted to be paid for their services which made the economy even worse.

Frequency modulation the amplitude

Frequency modulation the amplitude INTRODUCTION In frequency modulation the amplitude is kept constant and the frequency is modulated by the amplitude of the modulating signal. The modulation index for fm is m = maximum frequency deviation/modulating frequency. FM signal can be represented as:- v = ac sin(wct + m sin wmt ) ABSTRACT Frequency modulation is a type of modulation where the frequency of the carrier is varied in accordance with the modulating signal. The amplitude of the carrier remains constant. The information-bearing signal (the modulating signal) changes the instantaneous frequency of the carrier. Since the amplitude is kept constant, FM modulation is a low-noise process and provides a high quality modulation technique which is used for music and speech in hi-fidelity broadcasts. In addition to hi-fidelity radio transmission, FM techniques are used for other important consumer applications such as audio synthesis and recording the luminance portion of a video signal with less distortion. There are several devices that are capable of generating FM signals, such as a VCO or a reactance modulator. Frequency Modulation is abbreviated FM. Definitions An important concept in the understanding of FM is that of frequency deviation. The amount of frequency deviation a signal experiences is a measure of the change in transmitter output frequency from the rest frequency of the transmitter. The rest frequency of a transmitter is defined as the output frequency with no modulating signal applied. For a transmitter with linear modulation characteristics, the frequency deviation of the carrier is directly proportional to the amplitude of the applied modulating signal. Mathematical Analysis of FM As was done with AM, a mathematical analysis of a high-frequency sine wave, modulated by a single tone or frequency, will be used to yield information about the frequency components in an FM wave, FM power relations, and the bandwidth of an FM signal. From the definition of frequency deviation, an equation can be written for the signal frequency of an FM wave as a function of time: fsignal = fC + kf eM(t) = fC + kf EM sin?Mt And substitution of d = kf EM yields: fsignal = fC + d sin?Mt But what does this equation indicate? It seems to be saying that the frequency of the transmitter is varying with time. This brings up the same type of problem that was observed when we looked at a time display of AM and then performed a mathematical analysis in an attempt to determine its frequency content. With AM, the signal appeared to be a sine wave thats amplitude was changing with time. At the time, it was pointed out that a sine wave, by definition, has a constant peak amplitude, and thus cannot have a peak amplitude that varies with time. What about the sine waves frequency? It also must be a constant and cannot be varying with time. As was the case with AM, where it turned out that our modulated wave was actually the vector sum of three sine waves, a similar situation is true for FM. An FM wave will consist of three or more frequency components vectorially added together to give the appearance of a sine wave thats frequency is varying with time when displayed in the time domain. A somewhat complex mathematical analysis will yield an equation for the instantaneous voltage of an FM wave of the form shown here: eFM(t) = EC sin(?Ct + mf sin?Mt) where EC is the rest-frequency peak amplitude, ?C and ?M represent the rest and modulating frequencies, and mf is the index of modulation. This equation represents a single low-frequency sine wave, fM, frequency modulating another high-frequency sine wave, fC. Note that this equation indicates that the argument of the sine wave is itself a sine wave. The Index of Modulation The index of modulation, mf, is given by the following relationship: A few more comments about the index of modulation, mf, are appropriate. As can be seen from the equation, mf is equal to the peak deviation caused when the signal is modulated by the frequency of the modulating signal; therefore, mf is a function of both the modulating signal amplitude and frequency. Furthermore, mf can take on any value from 0 to infinity. Its range is not limited as it is for AM. FM Power Relations Recall that for an FM wave the amplitude of the signal, and hence the power, remains constant. This means that the power in the individual frequency components of the wave must add up to the transmitter output power. Furthermore, if the modulation index changes, the total power must redistribute itself over the resulting frequency components. If there is no modulation, then mf = 0 and J0 = 1.0. Mathematically, this can be shown by the following: Prest freq = J0 power 2 Ptrans or Prest freq = Ptrans for mf = 0.0. To determine the power for any individual frequency component, we can use the following relation: Pn = Jn 2(mf) Ptrans 4.11 Furthermore, the total signal power will be given by: Ptotal = (J0power2 + 2J1power2 + 2J2power2 + 2J3power2 + ) Ptrans. The Effect of Noise on FM Recall AM and the effect of noise on it. Random electrical variations added to the AM signal altered the original modulation of the signal. For FM, noise still adds to the signal, but because the information resides in frequency changes instead of amplitude changes, the noise tends to have less of an effect. Expanding upon this idea a bit, one notes that the random electrical variations encountered by the FM signal will indeed cause distortion by jittering the frequency of the FM signal. However, the change in frequency modulation caused by the jittering usually turns out to be less than the change in the amplitude modulation caused by the same relative amplitude noise variations on an AM signal. Also unlike AM, the effect of the frequency jittering becomes progressively worse as the modulating frequency increases. In other words, the effect of noise increases with modulation frequency. Pre-Emphasis and De-Emphasis To compensate for this last effect, FM communication systems have incorporated a noise-combating system of pre-emphasis and de-emphasis FM Generation Techniques FM signals can be generated using either direct or indirect frequency modulation. Direct FM modulation can be achieved by directly feeding the message into the input of a VCO. For indirect FM modulation, the message signal is integrated to generate a phase modulated signal. This is used to modulate a crystal controlled oscillator, and the result is passed through a frequency multiplier to give an FM signal DIRECT FM GENERATION The simplest method for generating FM directly is to vary the frequency of an oscillator. A capacitance microphone or a varactor diode may be used as part of the oscillators frequency determining network. The capacitor microphones capacitance varies in response to the intensity of the sound waves striking it, making the oscillators frequency vary as the amplitude of the sound varies. The varactor diodes capacitance depends on the voltage across it. Audio signals placed across the diode cause its capacitance to change, which in turn, causes the frequency of the oscillator to vary. INDIRECT FM GENERATION While it is not possible to vary the frequency of a crystal oscillator directly, it is possible to vary its phase. The resulting PM signal can be used to create FM. This is the basis of the Armstrong modulator.The mathematics required to analyze the Armstrong modulator completely are complex, so we will discuss only the basic circuit operation. An audio signal is passed through a preemphasis network and then an integrator, a special network whose output is the time integral of the input signal.. In this way an FM signal is generated.The Armstrong modulator cannot produce much deviation, so combination of multipliers and mixers are used to raise the carrier frequency and the deviation. The multipliers are used to multiply the carrier and the deviation. The mixers are used to decrease the carrier, while keeping the deviation constant so that additional multiplier stages can be used to obtain more deviation. FM Performance FM Spectrum A spectrum represents the relative amounts of different frequency components in any signal. Its like the display on the graphic-equalizer in your stereo which has leds showing the relative amounts of bass, midrange and treble. These correspond directly to increasing frequencies (treble being the high frequency components). It is a well-know fact of mathematics, that any function (signal) can be decomposed into purely sinusoidal components (with a few pathological exceptions) . In technical terms, the sines and cosines form a complete set of functions, also known as a basis in the infinite-dimensional vector space of real-valued functions (gag reflex). Given that any signal can be thought to be made up of sinusoidal signals, the spectrum then represents the recipe card of how to make the signal from sinusoids. Like: 1 part of 50 Hz and 2 parts of 200 Hz. Pure sinusoids have the simplest spectrum of all, just one component: In this example, the carrier has 8 Hz and so the spectrum has a single component with value 1.0 at 8 Hz . The FM spectrum is considerably more complicated. The spectrum of a simple FM signal looks like: The carrier is now 65 Hz, the modulating signal is a pure 5 Hz tone, and the modulation index is 2. What we see are multiple side-bands (spikes at other than the carrier frequency) separated by the modulating frequency, 5 Hz. There are roughly 3 side-bands on either side of the carrier. The shape of the spectrum may be explained using a simple heterodyne argument: when you mix the three frequencies (fc, fm and Df) together you get the sum and difference frequencies. The largest combination is fc + fm + Df, and the smallest is fc fm Df. Since Df = b fm, the frequency varies (b + 1) fm above and below the carrier. A more realistic example is to use an audio spectrum to provide the modulation: In this example, the information signal varies between 1 and 11 Hz. The carrier is at 65 Hz and the modulation index is 2. The individual side-band spikes are replaced by a more-or-less continuous spectrum. However, the extent of the side-bands is limited (approximately) to (b + 1) fm above and below. Here, that would be 33 Hz above and below, making the bandwidth about 66 Hz. We see the side-bands extend from 35 to 90 Hz, so out observed bandwidth is 65 Hz. You may have wondered why we ignored the smooth humps at the extreme ends of the spectrum. The truth is that they are in fact a by-product of frequency modulation (there is no random noise in this example). However, they may be safely ignored because they are have only a minute fraction of the total power. In practice, the random noise would obscure them anyway. Frequency Response Frequency response is a specification used in amplifiers, pre-amplifiers, CD players, tape decks and other audio components to measure how uniformly it reproduces sounds from the lowest tones to the highest. An amplifier or other component should preserve the loudness relationship between various instruments and voices and should not over or under-emphasize any frequency or tone. This is known as flat frequency response. Bandwidth As we have already shown, the bandwidth of a FM signal may be predicted using: BW = 2 (b + 1 ) fm where b is the modulation index and fm is the maximum modulating frequency used. FM radio has a significantly larger bandwidth than AM radio, but the FM radio band is also larger. The combination keeps the number of available channels about the same. The bandwidth of an FM signal has a more complicated dependency than in the AM case (recall, the bandwidth of AM signals depend only on the maximum modulation frequency). In FM, both the modulation index and the modulating frequency affect the bandwidth. As the information is made stronger, the bandwidth also grows. Applications of frequency modulation: Broadcasting: FM is commonly used at VHF radio frequencies for high-fidelity broadcasts of music and speech . Normal (analog) TV sound is also broadcast using FM. A narrow band form is used for voice communications in commercial and amateur radio settings. The type of FM used in broadcast is generally called wide-FM, or W-FM. In two-way radio, narrowband narrow-fm (N-FM) is used to conserve bandwidth. In addition, it is used to send signals into space. Sound: FM is also used at audio frequencies to synthesize sound. This technique, known as FM synthesis, was popularized by early digital synthesizers and became a standard feature for several generations of personal computer sound cards. Radio: An example of frequency modulation. This diagram shows the modulating, or message, signal, xm(t), superimposed on the carrier wave, xc(t) The modulated signal, y(t), produced from frequency-modulating xc(t) with xm(t). A Method of Reducing Disturbances in Radio Signaling by a System of Frequency Modulation called radio FM. As , wideband FM (W-FM) requires a wider signal bandwidth than amplitude modulation by an equivalent modulating signal, but this also makes the signal more robust against noise and interference. Frequency modulation is also more robust against simple signal amplitude fading phenomena. As a result, FM was chosen as the modulation standard for high frequency, high fidelity radio transmission: hence the term FM radio (although for many years the BBC called it VHF radio, because commercial FM broadcasting uses a well-known part of the VHF band; in certain countries, expressions referencing the more familiar wavelength notion are still used in place of the more abstract modulation technique name).A high-efficiency radio-frequency switching amplifier can be used to transmit FM signals (and other constant-amplitude signals). For a given signal strength (measured at the receiver antenna), switching amplifiers use less battery power and typically cost less than a linear amplifier. This gives FM another advantage over other modulation schemes that require linear amplifiers, such as AM and QAM. REFRENCES; http://en.wikipedia.org/wiki/Frequency_modulation http://www.tech-faq.com/frequency-modulation.shtml http://www.fas.org/man/dod-101/navy/docs/es310/FM.htm http://www.answers.com/topic/frequency-modulation

Grammer :: essays papers

Grammer ADVERBS & HELPER VERBS ~the purpose is to show where, when, how, or to what degree ~adverbs are words ending in ly Adverbs not ending in ly: all, almost, also, always, away, ever, forward, later, maybe, most, never, nevertheless, now, not, often, only, onward, perhaps, sometime(s), soon, then, too, very, up helper verbs: be, am, is, are, was, were, have, has, had, have been, has been, had been, shall, will, do, did, may, can, must, might, could, would, should PREPOSITIONAL PHRASES some of the most common prepositions: about, above, according to, across, after, against, along, among, as, at, because of, before, behind, below, beneath, beside, between, beyond, but, by, down, during, except, for, from, in, into, like, near, of, off, on, on account of, outside, outside of, over, past, since, through, to, toward, under, until, up, upon, with, within, without, Examples: 1. (For many years) the lighthouse has been the most famous landmark (along the coast.) 2. It has warned (ships at sea)(of the countless dangers)( from the fog storm.) PRONOUNS subject: Object: I me he him

Misguided American Dream in Arthur Millers Death of a Salesman :: Death Salesman essays

Misguided American Dream in Arthur Miller's Death of a Salesman Death of a Salesman deals with hopes and dreams gone wrong. This does not necessarily have to be the "American" dream as such, because all people share the same hopes and dreams, regardless of nationality. The underlying factor, and the inevitable truth is that we all have to dream, dreams are important for human existence. It is evident to the reader that for Willy, his ultimate dream was to follow in the footsteps of Uncle Ben and become a successful salesman. Unfortunately for Willy, most of his dreams are illusions, yet he is unable to come face to face with this fact. At the plays conclusion, Biff is susceptible to succumb to the fact that his father, Willy, did in fact have "all the wrong dreams", and the reader will agree that this is ultimately what lead to Willy's downfall. Willy's false hopes and dreams are evident in the fact that he wants to be a mirror image of his brother Ben. "The man knew what he wanted and went out and got it!" Willy believes that Ben has the "ultimate life", and strives to follow in the dream of being a successful salesman. This brings forth the notion of Willy kidding himself, and not knowing any different.   "The jungle is dark but full of diamonds." The jungle metaphor is continually bought to the reader's attention throughout the novel. Like Ben, Willy hopes to strike it rich in the business world of New England.   Yet Willy never finds the diamonds (success), and he leaves life without fortune or fame.   In many ways, the jungle also represents the American Dream ideal that Miller often criticized. It is the opinion of Willy that the job of a salesman is the most enjoyable of all jobs. "...And the smile on your face" gives the reader the notion that Willy is happy in his job, which Willy himself leads him self to believe. Evidently, this only turns out to be another illusion that Willy has created for himself. Nearing the novels conclusion, it is evident to the reader that Willy is unable to maintain this smile, and he is no longer happy in his job. Willy's illusions throughout the novel are also evident to the educated audience.

juveniles and the death penalty :: essays research papers

The American Revolution: Revolutionary or Not? In determining whether or not the American Revolution was a true revolution, one must clearly define the term ?revolution?. Historians believe that for a war to be deemed a revolution it must encompass social, religious, economic, and intellectual dimensions as well as political change. I believe that the American Revolution conclusively exhibited all of these dimensions. Socially, America began with modern values unlike those of their British ancestry. The moral of equality was the foundation on which our nation began. When the tension grew between the colonies and England, the new ideology spread and began to widen to include almost all people. First, people began to realize that they did not necessarily live in a way which modeled their belief in equality. This, in itself shows the beginnings of a true revolution in that the people begin to see the need for change even within their own families, social groups, and lifestyles. After recognizing changes were needed, transformations began to occur in the colonies. For instance, a new position for women as upright citizens and leaders of the society emerged, and most states granted women equality of inheritance. Also, social distinctions such as status-seating at church and membership to private social clubs were attacked and diminished. People began referring to themselves as Mr. or Mrs., terms that illustrated the equality of all people, regardless of class or prestige. In addition, because most men were allowed a vote, education of the population became a priority. Nationalism spread as the people of America came to understand their common goals and needs. The concept of constituent power allowed for social changes also, as the people came to believe that the power rested in the will of the people, which caused them to gain self trust and esteem. People focused so much on equality and the rights of all people that in the south, several states passed laws which repressed the importation of slaves and made it easier to free slaves; in the north, slavery was outlawed in most states, and abolitionist groups arose. During the Revolution, the American people also formed new intellectual standpoints. The most respected thinkers of the time began to shift their focus to concentrate on creating political change. Men such as Ben Franklin, and other inventors theologists, and philosophers began to focus on concerns such as economic growth, constitutional revision, and westward expansion, rather than philosophy and theology.

Marketing Nestle

Nestlà © Purina Pet Care Company (NPPC) has been in existence for 115 years. Nestle’ is a pioneer in pet food and the North American market leader and has consistently demonstrated solid financial results. In 2010 Nestle’ Purina Pet Care Co. or (NPPC) were the proud recipients of the Malcolm Bridge Award.Companies who are honored with this award are achievers of pure performance excellence. The president of the United States presents the Malcolm Bridge award to companies who have demonstrated quality management and therefore they are recognized in an effort raise the awareness of excellence within our business world (ASQ.org, 2013).What marketing elements did NPPC utilize as possible contributors to receiving such an honor? The product mix of this company is diverse and includes a product line consisting of items for both cats and dogs. The width of the product mix includes; dry dog food, wet dog food, dog treats, dog litter, dog training pads, dry cat food, wet cat fo od, cat treats and kitty litter (purina.com, 2013).The second part to the product mix is the depth. According to Lamb, Hair and McDaniel, â€Å"the product line depth is the number of product items in a product line† (2012, pg. 159). NPPC offers eleven products in the cat product line and thirteen products in the dog line. Together these make a good product mix.NCCP also has some major elements in their brand name, some of which are very familiar for those who have pets. The brand names include those such as Purina Alpo, Purina One, Purina Dog Chow, Friskies, Tidy Cats and Fancy Feast to name a few. The major elements of this brand would be the push for healthy pet food which in turn makes a healthy pet, all the while offering nutrition and making both the owner and the pet happy.In order to create a happy customer there are service characteristics that must be met. NPPC offers several. To mention a few let’s begin with the some of the most important service characteri stics. One critical intangible service would include NPPC’s quality. They provide large volumes of their products with a proven track record of consistently high quality and very limited defects or issues. NCCP also creates customer loyalty, healthier pets and longevity by providing a quality product (baldridge.nist.gov, 2010).Along with quality NCCP offers excellent customer service and provides dedicated service teams to insure this service is maintained. Ethics would be another intangible service possessed and research is done to ensure cat and dogs are always treated humane. NCCP participates in a formal ethics program and stays involved in the community. They are also listed as a best place to work (baldridge.nist.gov, 2010).Finally, the dedication to service quality is proven by five different components. The first of which is reliability. NPPC is labeled a most trusted pet care company and strive to earn to more every day by being reliable (baldridge.nist.gov, 2010). R esponsiveness and providing prompt service is measured continually and new innovation and new product development has helped continuous improvement in this area (baldridge.nist.gov, 2010).Assurance has been achieved by proving that NPPC cares about the costumers and their pets. The ethical research done to ensure the nutritional values of each and every product speaks volumes (baldridge.nist.gov, 2010).Empathy is very high on the list of ser quality objectives. This is proven by the massive research, surveys and studies done to make sure each customer has a voice and each pet gets the personal attention they need to have a long and prosperous life. The knowledge of the customers, pets and retailers is unparalleled (baldridge.nist.gov, 2010).Last but not least are the tangibles. The manufacturing and distribution of NPPC products are an example of a tangible service that is performed with excellence and technology of equipment and supplies are updated consistently and held at very hi gh standards. The customer service reps are also held to  standards and treat each retailer, customer and pet with the very highest regards at all times. It is very apparent looking at the track record of NPPC, why they received the Malcolm Baldrige Award. Every element of the company is held to the highest standards possible and the care and attention provided to their customers is phenomenal. Many companies could learn some valuable lessons by looking at the achievers of this highly honored award.

Benefits of Studying Psychology Essay

Question / Topic: Some critics argue that there is no such thing as a psychologically whole person because everyone is fundamentally flawed. Hence, there should not be a need for learning Psychology in this world. What is your response to this? Introduction: What is psychology? The word ‘psyche’ means breath,spirit,soul and logia means study of. It is a scientific study of behavior and mental process. Psychology is all around us like the way people behave, talk and do things. It is an interesting field to learn and it helps in crafting us into a whole person. Thus, the communication skill with them is increased also. †¢A good example for this will be in the education field, where a teacher who needs to deal with children will benefit by learning how to engage in an interesting way of teaching to attract the attention of his/her students. Concluding Sentence: Therefore, we see clearly that a better understanding of human mind and thought process helps to add quality and depth to our relationships with people around us. Topic sentence : Apart from that, learning psychology creates stronger conflict and problem solving capability in a person. Most people tend to lose their mind and become nervous, emotional and unable to decide when a problem arises. This can be avoided by a person who learns psychology. †¢When a problem comes up, a person who has learned psychology can take time to evaluate the situation, evaluating every option available and not to rush thru decision. In other words, he can be logical and not emotionally driven t o make a decision. †¢Addition to that, psychology also teaches people to help empathize others and use the knowledge they have to bring harmony among others. Concluding Sentence: In a nutshell, psychology assists in solving problems and handling conflicts. Conclusion : These are the benefits of learning psychology. It is true that there is no one who is born into this world as a psychologically whole person, but a person can be cultivated into one. Learning psychology plays a major part in this. That is why it is also said as ‘the science of soul’. Understanding of human behavior and use of knowledge learned from psychology helps a person in many ways in their daily life. Thus, the need to learn psychology is indeed very important.