Cathedral By Raymond Carvers Essays - Cathedral, Humility

Cathedral By Raymond Carvers "For now we see through a glass darkly; but then face to face: now I know in part; but then I shall know even as I am known" (1 Corinthians 13). The narrator of Raymond Carver's "Cathedral" is a man living a life of monotony, continuously feeding the cold and bigoted mind that we witness for the first part of the story. The process of guiding Robert through the drawing of the cathedral, removes the narrator from that dark looking glass and initiates a tranformation in which he is compelled to meet himself face to face; this awakening stirs the narrator's humility, imagination, and faith. It is human nature to embrace preconceptions regarding the facets of daily life, from politics to people. It is, as well, innate to consider oneself better than another. An awakening such as the narrator's, however, ruptures the protective shield that surrounding steadfast biases, and forces the person to assess their position in the greater schema of humankind. A bias that surfaces early on, is the mention of Robert's wife, "Beulah!" The narrator exclaims, "That's a name for a colored woman." (Carver, "Cathedral," 182) Here, by attaching a stereotype to a simple name, he exhibits the precise indiscretion of a closed-minded bigot, and then eventually reaches humility through his awakening. The narrator possesses several other prejudices that also hinder his humility. Later on, for example, the narrator sees Robert for the first time and the man's appearance startles him: "This blind man, feature this," he says, "he was wearing a full beard! A beard on a blind man!" (183) Later still, the narrator reinforces his portrayal of an ignorant, presumptuous man when he notices that Robert doesn't "use a cane and he [doesn't] wear dark glasses, [having] always thought dark glasses were a must for the blind." (183) However, the narrator sheds these stereotypes once he engages in the 'cathedral' conversation with Robert; the two begin to compare how well each of them envisions a cathedral. For instance, Robert gives facts that he has just heard off the television, demonstrating his limited knowledge. The narrator then attempts a description of a Cathedral, "they're really big," the narrator explains, "they're massive;" (188), and subsequently realizes just how little he knows as well. The narrator realizes that with the gift of sight he can really see little more than a blind man . . . And it is here that the narrator awakens to his newly humbled -- equal -- position alongside Robert. Up to this point, the narrator fancied himself a superior person because of his sight. Suddenly, with this moment of awakening, down came that shield protecting his closed-minded presumptions. By engaging in the same action that helped him realize his humbleness, the narrator retrieves his imagination. For so long he had been stifling his innate creativity, choosing instead to allow outside forces create images and art for him. Robert coerces the narrator into sketching a cathedral, unlocking the door behind which the narrator had been keeping his imagination. This brings to light just how important and self-fulfilling that imagination had once been to him and could be again: "So I began. First I drew a box that looked like a house. It could the house I lived in. Then I put a roof on it. at wither end of the roof, I drew spires. Crazy . . . I put in windows with arches. I drew flying buttresses. I hung great doors. I couldn't stop." (189/190) This sketch has initiated another awakening. That is, the narrator placed in perspective what a steady diet of television and drinking had been holding him back from; here he is reacquainted with his estranged imagination, not able to stop drawing because with the sketch comes a flood of new spiritual enlightenment. The narrator doesn't rest here for long, however, forced to stretch his imagination even farther when the television goes off the air. Now the narrator is forced to use his imagination in its purity. "'Close you eyes now,' the blind man said to me. I did it. I closed them just like he said. . . 'Keep them that way,' he said. He said, 'Don't stop now. Draw.'" (190) The narrator completes his drawing and, without even opening his eyes, knows and feels its beauty because he was compelled to draw by his own mind, unaided by external imaginations. "My eyes were still closed. I was in my house. I knew that. But I didn't feel like I was inside anything." (190) The narrator's awakening

Media essays

Media essays The case that I decided to focus on is an older abuse case, but it has recently been resolved in the courts. It is a child abuse case involving James and Bonnie Zeleski. They were both charged with abusing their infant daughter. The child was brought to the hospital with a fracture in each leg, a fracture in each arm, a thigh fracture, three broken ribs, a ripped esophagus, pneumonia, malnourished and several other cuts and bruises. The girl was transferred to an Omaha hospital. The father, James, was charged on June 3, 1998 with Class 4 Felony Child Abuse. His wife, Bonnie, was later charged and convicted of a Class 3 Felony. James was sentenced to three years probation and six months in jail. His wife was sentenced to 15 to 18 months in prison. I think that this case was fairly portrayed by the media. I know at the time, there were several letters to the editor and opinion printed on the subject, but the Grand Island Independent seemed to be fair and stick to the facts. It was a horrible crime and I think they did a good job being unbiased. I think that it is a good idea to publicize crimes like this. From my other studies, I have learned that the informal sanctions, public humiliation and shame, are far more effective than the formal sanctions in preventing crime. When people who are having a hard time dealing with being a parent see something like this in the media, they may stop to think about their actions. A good idea would be to run several articles on where parents can go to for help. The combination of the two, may help prevent this from happening to another child. As a mother I have a definite interest in this crime. I cannot even begin to understand how anyone could do something like that to someone so helpless. I am also interested in this case from the legal perspective and how the case was resolved in the court system. I personally think that the sente...

Biomedical Ethics Essay Example | Topics and Well Written Essays - 1750 words

Biomedical Ethics - Essay Example This paper is going to discuss and analyse the dignity of human life in relation the different concepts, views and ideas proposed by some philosophers and scientists. Looking at the video ‘The Island’, significant science fiction themes are clearly echoed in todays culture of medical ethics, class conflict and organ transplantation. Corporate ethics and prison populations are also reflected in the video. The main theme in the video is corporate abuse of human beings. Starred by Ewan McGregor, the video slowly builds up the theme and displays how the wealthy class engages in immoral activities in the hope that, they might be turned into immortals. By not fearing to destroy their vital body organs by engaging in drug abuse, excessive drinking, smoking and eating junk foodstuffs, these people show how wealth can be used to manipulate the good values and morality in humanity. The Island is an organization in the contemporary corporate world that makes its clients believe that it produces entirely new body organs in the laboratory yet this is not the case. It instead clones the clients and grows exact human beings whose body parts will be used in case of transplantations. The video is a true reflection of what is taking place in the contemporary world. The wealthy people and organizations are abusing corporate ethics in order to fulfil their desires. According to Kateb (2011), some doctors, including the highly revered Harry Sharp believed that social failure was a medical problem. This was in support of the scientific Eugenics movement sought to do away with some vices and immoral acts among human beings. Poverty, alcoholism, prostitution and criminal behaviour were the core vices that they sought to eliminate. Others included schizophrenia, rebelliousness and weak mindedness. Heated debates and arguments have however emerged concerning some of these

Are low risk women in normal labor receiving too many interventions Essay

Are low risk women in normal labor receiving too many interventions - Essay Example In normal labor the package of routine care becomes very flexible one. These interventions depend upon the place of delivery; at home most of the time moral support and attachment are the major interventions while at a well-equipped health facility the staff utilizes more interventions in the management of any pregnant women. (2) In the UK, the routine practice at the time of delivery is carrying out various activities related to any task of maternal and fetal care. Usually, the intensity and frequency of these activities crosses any line or level recommended. Most of the time these activities are carried out without any supportive evidence and at times these may become dangerous instead of beneficial. Findings from the study carried out by Hofmeyr stressed on the inconclusive evidence of routine use of oxytocin, routine amniotomy, continuous electronic fetal heart rate, etc (2). Use of analgesia has got its own untoward effects. Epidural analgesia may convert the normal labor to a prolonged labor at one end; further, it may also increases the probability of performing other interventions, as they are needed due to the long duration of labor. So after getting epidural analgesia which results in prolonged labor eventually results in exhaustion on the side of the woman with weaker and infrequent labor pains fro which drugs for augmentation are required supported by episiotomy. (3) The frequency and types of interventions used during intrapartum period in the UK especially in low risk women has not been looked for and estimated. (4) There are strong recommendations not to overuse interventions when they are not indicated. (5) There is a common agreement of obstetricians and midwives that most of the obstetric interventions cannot be explained. (6) Therefore, as is well known that these interventions are at times dangerous especially when used in excess and at the same time the frequency of use of these interventions is not available. To get reliable information on the utilization of these interventions appropriately a study is proposed with a research question of are low risk women in normal labor receiving too many interventions Objectives To look for level of intrapartum interventions used in normal labor in the UK. Methodology Study design A cross sectional survey will be carried out to reach the objective of this study. Sampling frame A sampling frame of all the consultant maternity units in Great Britain was obtained from the annual returns to the Royal College of Obstetricians and Gynecologist (RCOG). This list contains the data, which is believed to be almost complete. Aim was to complete data collection in one year. The sampling frame captured 237 hospitals but the final number of hospital to be included in the study was 226. The hospitals with less than 1000 births per annum were excluded from the list. Sample size determination To get an appropriate number of women to capture all major interventions, a sample size of 4040 women was finalized. It was decided to collect information from 40 women from each hospital to complete the data collection in an appropriate time without putting extra burden on the hospitals. For this purpose, 101 hospitals were randomly selected from the sampling frame and from each hospital

Debreifing Research Proposal Example | Topics and Well Written Essays - 500 words

Debreifing - Research Proposal Example Data backup and system documentation had not been addressed (Schmidt, Erek, Kolbe & Zarnekow, 2009). Communication channels in the company were poor thus retrieving information from responsible persons was impossible. â€Å"Lassiter was finding it very difficult to gain information from Kovecki on the progress and status of the system conversion† (Midsouth chamber of commerce, n.d.). A person who clearly understands the roles to be undertaken must head each section/department. Information technology department had to employ a full-time staff with experience in membership organizations and experience on the accounting software to ensure full running of the new system. Simon Kovecki was employed but lacked experience in membership organizations and the accounting software. He wasted a couple of months in learning how the organization operates and training himself on how to use the system. All systems must contain documentation to ensure ease of use (Schmidt, Erek, Kolbe & Zarnekow, 2009). Decision-making role must be well defined to ensure decision pertaining the company is made at the right time; immediately. A specific department to avoid role duplication should do purchasing. UNITRACK software is the best since it is powerful and can handle the matters of the MSCC Company even during its growth. The software is user-friendly and cheap. UNITRAK software firm could have been given chance to install the software and train all the employees as this could have cut cost on training and relieve Kovecki the computer analyst from the training job to handle other system affairs of the company like interviews. Implementation cost could have been cut off since UNITRAK would have done this free of charge (Schmidt, Erek, Kolbe & Zarnekow, 2009). Information technology systems are always complex and need expertise to use. Transforming from the old system to new system (target system) is challenging. Before actual

Care Of Clients With Mental Health Problems

Care Of Clients With Mental Health Problems This essay will look at the relationship between schizophrenia and bio psycho social issues it will also explore the concept of recovery and also look at some of the approaches that are used to promote the recovery process. The National Health Service (2005) describes schizophrenia as a mental illness with substantial short and long term consequences for individuals, family, health and clinical services and society. One in hundred people experience schizophrenia in their lifetime with highest incidence of the disease in late teens and early 20s. People with schizophrenia suffer distress and long term disability and there is a lot of accompanied stigma and prejudice involved with the disease that can have negative effects on employment, relationships and life satisfaction. A persons family is completely destroyed with schizophrenia and carers and family members also carry the burden of the disease and caring the person for a long time. Schizophrenia is a severe mental disorder characterized by profound disruptions in thinking, affecting language, perception and thee sense of self. It often includes psychotic experiences, such as hearing voices or delusion. It can impair functioning through the loss of an acquired capability to earn a livelihood or the disruption of studies (WHO, 2009) Schizophrenia is not caused by one single factor but a combination of different factors these factors are biological, psychological and social. This is what is known as the bio psycho social model of schizophrenia (Santrock, 2007). There are thought to be many causes of schizophrenia one of these are genetic factors. Riley Kendler (2006) state that 70% of people who develop schizophrenia have a relative who has schizophrenia, the closer the relation the more likely a person is to get the disease if a person has an identical twin with schizophrenia they have a 50% chance of developing schizophrenia. There is a genetic component to schizophrenia which means someone may be predisposed to developing schizophrenia but it does not mean that they are pre-determined to develop the illness. Biological factors can include age or a virus and environmental factors for example life stressors can trigger an onset of schizophrenia. Stressful life events that occur can include having a baby, losing a job, moving house or losing someone who is close but not everyone who goes through these stressful situations will be diagnosed with schizophrenia as some people can handle stressful situations better than other people will. Risk factors may be different for different individuals while one person may develop schizophrenia due largely to a strong family history of mental illness (e.g. a high level of genetic risk), someone else with much less genetic vulnerability may also develop the disease due to a combination of pre-pregnancy factors, pregnancy factors, social and family stress or environmental factors that they experience during their childhood, teen or early adult years. This suggests that individuals possess different levels of vulnerability to schizophrenia, which are determined by a combination of biological, social and/or psychological factors. It is proposed that vulnerability to schizophrenia will result in the development of problems only when environmental stressors are present (Riley Kendler, 2006). If the vulnerability of an individual is sufficiently high, relatively low levels of environmental stress might be sufficient to cause problems. If the vulnerability is much less, problems wil l develop only when higher levels of environmental stress are experienced (NHS report, on Schizophrenia 2005). In mental health recovery has a lot of different definitions and does not always refer to a person having complete recovery from mental health problems in the same way that a person can fully recover from having physical health problems. A person not only has to recover from the distress and trauma of psychotic experiences they also have to deal with social exclusion, discrimination, stigma, loss of position in society, feelings of hopelessness, possible forced hospitalisation and the trauma of receiving a diagnosis. The National Institute of Mental Health (2009) suggests that there is no single meaning of the concept of recovery for people with mental health problems, but the easiest way to explain the recovery model is one of hope and that it is possible for a persons meaningful life to be restored, despite serious mental illness. Recovery is often referred to as a process, outlook, vision, and conceptual framework or guiding principle (Watkins, 2007). The Mental Health foundation (2007) state that the recovery process should provide a holistic view of mental illness that focuses on the person as a whole and not just their symptoms. They also believe that recovery from severe mental illness is possible and it is a journey rather than a destination but it does not necessarily mean getting back to where a person was before their diagnosis recovery will happen in fits and starts and, like life it has many ups and downs, calls for optimism and commitment from all concerned, is very much influenced by peoples expectations and attitudes requiring a well organised support system this can be from family, friends or professionals it also requires mental health service providers to accept and take on new ways of working. Recovery highlights that while people may not have full control over their symptoms, they can have full control over their lives. According to the National Institute of Mental Health recovery is not about getting rid of mental health problems. It is about being able to help people beyond their problems helping the person to be able to recognise and develop the opportunities that connect their abilities, interests and dreams. Mental illness and social attitudes such as stigma that still surrounds mental illness can often impose restrictions on people experiencing ill health (Hinshaw, 2007). Recovery looks past these restrictions to help people achieve their objectives. A care pathway is an outline of anticipated care, placed in an appropriate timeframe, to help a patient with a specific condition or set of symptoms move progressively through a clinical experience to positive outcomes. The Department of Health Dual Diagnosis Practice Guide (2002) state that someone with dual diagnosis Schizophrenia and substance misuse issues will have an integrated care pathway as their care can be complex as there is likely to be multi agency involvement. The Summary of Assessments of Risk and Need (SARN) is a tool designed to be used in mental health services for describing service users needs for care. (Self et al 2008). It provides a brief description of the needs of people entering into Mental Health services or presenting with a possible need for change in a care plan. It was developed to aid in the process of establishing a classification of service users based on their needs so that appropriate service responses could be developed both at the individual and service level. It allows professionals from a range of backgrounds to summarise their assessments in a shared format. Thus it provides a common language for describing health states and related social conditions and improves communication between different users including service users themselves (National Health Service, 2009). There are several strategies used to promote the recovery process and these can include pharmacological interventions, CBT, family therapy. Those who have family benefit most if their families are well informed about the illness have support and skills to deal with the ill family member. Social skills training, vocational assistance and environmental modification help support recovery because if someone is in control of their finances have a job that they can go to this is likely to help with their personal growth and their self esteem. Cognitive behavior therapy can help reduce the distress and disability caused by symptoms of schizophrenia. Improve understanding and self management, reduce the risk of further relapse, improve mood and self esteem it involves client as an active participant in treatment. NICE guidelines (2009) state that psychological interventions should play a key role in the treatment of schizophrenia and that the best evidence is for CBT and family intervention. NICE guidelines now explicitly recommend CBT to be offered as a treatment option and family interventions should be available to families who are living with someone with psychosis or who are in close contact with someone with psychosis. CBT offers a collaborative approach ensures client is at the centre of care and is an active participant in decisions about treatment; this enhances engagement with services (Freeman Felgoise, 2005). Motivational interviewing was originally developed as a treatment for drugs and alcohol addiction. However, it is now used with clients with psychosis to enhance compliance with medication (Rollnick Miller, 2002). It is also used for clients with a dual diagnosis of drug or alcohol use and psychosis (Haddock et al, 2002). Motivational interviewing is based on the theory of stages of change or cycle of change (Proschaska Diclemente, 1982). According to Rollnick Miller (2002) the different stages of change are; In pre-contemplation the person does not acknowledge a problem exists. In contemplation the person is ambivalent they are in two minds about what they want to do. In action the person is preparing and planning for change. When they are ready the decision to change is made and it becomes all consuming. In maintenance the change has been introduced into the persons life. Some support may still be needed through the maintenance stage. Lapse is a temporary return to old unhelpful thoughts, feelings or behaviours. Relapse is a full return to the old behaviour. Lapse and relapse are viewed as natural part of the Cycle of Change and do not assume failure. It does not mean that lapse or relapse is desirable or even always to be expected. It simply means that change is difficult, and it is unreasonable to expect anyone to be able to change a habit perfectly without any slip ups (Rollnick Miller, 2002). When a relapse o ccurs, several trips through the stages may be necessary to make lasting changes. Each time the person is encouraged to review, reflect and learn from their slip ups. Rollnick and Miller (2002), state that motivational interviewing is especially effective when clients are either in the pre-contemplation or contemplation stages. Relapse rates in psychosis are extremely high, even if people stay on their medication so it is always good practice to work closely with the client and their family and list early warning signs (Witkiewitz Marlatt, 2007). This can lead to an action plan that can be implemented to help spot signs of relapse. Once a list of early warning signs has been completed a detailed action plan can be drawn up this will usually include, which the client and their family should do if signs of relapse are spotted. These plans can include what services should respond to the client and families concerns and give a list of available resources e.g. extra medication, phone numbers to call in crisis. Doing this can be empowering for both the client and their family it can enhance the relationship between them and mental health services giving them more control over their treatment and also enables them to feel supported in practical ways (Witkiewitz Marlott, 2007) . As with all therapies there is always problems the main ones associated with CBT and motivational interviewing are initial engagement, encouraging people to talk about their symptoms and problems, funding, time limitations and resources and ensuring that skilled mental health workers have sufficient training in carrying out these therapies. Being diagnosed with schizophrenia shouldnt mean that a person cant live a full and happy life. With the right help and advice and continuing support from mental health services a person who suffers from schizophrenia should be able to work, build relationships and live a normal life just like anyone else. According to Mind (2009) this is due to a better understanding of schizophrenia the introduction of more effective medications and the increasing use of therapeutic interventions.

Smoking: Hazardous to Your Health Essay -- Argumentative Rebuttal Essa

Smoking: Hazardous to Your Health A about two weeks ago I read an essay called, â€Å"Thank You for Smoking†¦?† by Peter Brimelow. This essay’s main point tries to explain how smoking can be beneficial in some ways. Brimelow’s essay claims smoking can help while driving. Brimelow also thinks smoking can help protect personal freedoms along with benefiting health in some ways (141). Nonetheless, cigarette smoking is the single most preventable cause of premature death in the United States (Morbidity and Mortality Weekly Report). Clearly then, smoking is a very hazardous activity and causes many deaths. Driving and Smoking Brimelow informs his readers that smoking can increase alertness and dexterity which will help when driving (Brimelow 141). It has been confirmed that this is true. Although I do not smoke, should I if I am getting sleepy while driving? Fortunately, it is not necessary. There are many other aids that can help with alertness, such as caffeine. Many popular drinks such as coffee, cappuccino, or pop contain caffeine which can help eliminate tiredness. There are hazardous of smoking while driving also. Cigarettes can be cumbersome and a distraction while driving. If there is anything flammable in the vehicle, a lit cigarette poses a possible hazard. Also, if other people are in the car at the same time, they will be forced to inhale the dangerous toxins floating around. Freedom While talking about freedom and personal choices, Brimelows’ essay notes that we are able to â€Å"†¦judge, as individuals, that the reward outweighs the risk. This is called freedom†(141). It is difficult to provide everyone with their desires associated with smoking. I hate the sme... ...enefit in a few small ways, but has many more negative consequences. Smoking, along with second-hand smoke, has caused many preventable deaths in the United States. Smoking is obviously hazardous, along with being the cause of many deaths in the United States. Works Cited Brimelow, Peter. â€Å"Thank You for Smoking†¦?† The Genre of Argument. Ed. Irene L. Clark. Boston: Thomson-Heinle, 1998. â€Å"Cigarette Smoking-Attributable Mortality and Years of Potential Life Lost—United States, 1990† 19 Sept. 1998 Centers for Disease Control and Prevention. 18 March 2004 . Clark, Irene L. The Genre of Argument. Ed. Irene L. Clark. Boston: Thompson-Heinle, 1998. â€Å"OMA position paper on second-hand smoke† Nov. 1996 Ontario Medical Association. 16 March 2004 . Smoking: Hazardous to Your Health Essay -- Argumentative Rebuttal Essa Smoking: Hazardous to Your Health A about two weeks ago I read an essay called, â€Å"Thank You for Smoking†¦?† by Peter Brimelow. This essay’s main point tries to explain how smoking can be beneficial in some ways. Brimelow’s essay claims smoking can help while driving. Brimelow also thinks smoking can help protect personal freedoms along with benefiting health in some ways (141). Nonetheless, cigarette smoking is the single most preventable cause of premature death in the United States (Morbidity and Mortality Weekly Report). Clearly then, smoking is a very hazardous activity and causes many deaths. Driving and Smoking Brimelow informs his readers that smoking can increase alertness and dexterity which will help when driving (Brimelow 141). It has been confirmed that this is true. Although I do not smoke, should I if I am getting sleepy while driving? Fortunately, it is not necessary. There are many other aids that can help with alertness, such as caffeine. Many popular drinks such as coffee, cappuccino, or pop contain caffeine which can help eliminate tiredness. There are hazardous of smoking while driving also. Cigarettes can be cumbersome and a distraction while driving. If there is anything flammable in the vehicle, a lit cigarette poses a possible hazard. Also, if other people are in the car at the same time, they will be forced to inhale the dangerous toxins floating around. Freedom While talking about freedom and personal choices, Brimelows’ essay notes that we are able to â€Å"†¦judge, as individuals, that the reward outweighs the risk. This is called freedom†(141). It is difficult to provide everyone with their desires associated with smoking. I hate the sme... ...enefit in a few small ways, but has many more negative consequences. Smoking, along with second-hand smoke, has caused many preventable deaths in the United States. Smoking is obviously hazardous, along with being the cause of many deaths in the United States. Works Cited Brimelow, Peter. â€Å"Thank You for Smoking†¦?† The Genre of Argument. Ed. Irene L. Clark. Boston: Thomson-Heinle, 1998. â€Å"Cigarette Smoking-Attributable Mortality and Years of Potential Life Lost—United States, 1990† 19 Sept. 1998 Centers for Disease Control and Prevention. 18 March 2004 . Clark, Irene L. The Genre of Argument. Ed. Irene L. Clark. Boston: Thompson-Heinle, 1998. â€Å"OMA position paper on second-hand smoke† Nov. 1996 Ontario Medical Association. 16 March 2004 .

Agriculture and the Nitrogen Cycle Essay

Agriculture is an important industry that provides food for human consumption. The decrease of land available for agriculture coupled with the increase of human population has required that agricultural lands increase their output. This was achieved through the use of improved crop varieties, more productive livestock, better weed and pest control and the increased use of fertilizers, specifically nitrogen fertilizers which has linearly increased to 1. 2 Mt in the 1980s. However, farming also affects the environment. Increases in phosphorus and nitrate contents of water lead to increased biological activity and large concentrations of nitrate in drinking water create health hazards. J. K. R. Gasser studied the nitrogen cycles in agriculture and reported the results in his article â€Å"Agricultural Productivity and the Nitrogen Cycle. † Gasser (1982) explained that nitrogen is emitted from the soil or from animal effluents as ammonia, nitrous oxide or N2. Considerable amounts of nitrogen are also recycled directly as animal urine and feces. The preceding crops in agricultural lands also affect the amount of nitrogen released for the current crops. However, Gasser (1982) explained that no arable system provides enough nitrogen for the maximum production of crops such that additional nitrogen must be added in the form of fertilizers. Gasser (1982) reported that there is no evidence supporting that the increased use of nitrogen fertilizer also increases the total amount of nitrogen in soil-plant system. He stated that little of the nitrogen in circulation â€Å"will appear directly in the atmosphere or groundwaters, most will leave the agricultural system after one or more changes or subsidiary cycles† (Gasser, 1982, 313). Gasser (1982) concluded that the losses from the system must be at least as large as the known inputs. He persuaded to quantify the movement of nitrogen, the understanding of which would allow the losses from agricultural system to be minimized improving the utilization of nitrogen in farming and reducing its effects on the atmosphere and water. Reference Gasser, J. K. R. (1982). Agricultural productivity and the nitrogen cycle. Philosophical Transactions of the Royal Society B (Biological Science) vol. 296, no. 1082, 303-314.

Cantuyrbury Tales essays

Cantuyrbury Tales essays If one were to read The Canterbury Tales, by Geoffrey Chaucer, it is inevitable that one would sense Chaucers outright disrespect toward the medieval church. Through various descriptions of Church figures, brilliant characterization, and obvious comments Chaucer displays his evident antipathy toward the Church. Through his descriptions of certain religious figures he illustrates that they are the opposite of what they should be. Also, through the tales these travelers tell he shows the blasphemous struggles of power that the Church went through in the middle ages. To begin his mockery of the Church Chaucer begins with the Friar. In the Prologue, Chaucer writes ...For he was qualified to hear confessions, or so he said, with more than priestly scope; He had special license from the Pope. Obviously he is portraying the Friar as a liar, displaying his distrust toward the Church. When the Friar tells his tale, it is about the wickedness and corruption of Summoners which exhibits Chaucers amusement with the struggle for power by the Medieval Church. Chaucer again mocks the Friars character by portraying him as better than lepers, beggars and that crew. Friars by calling are supposed to be beggars who live on just enough to survive, which is exactly that which he sees himself above. Next on Chaucers ridicule list is the Pardoner. Chaucer describes him as a shameless and immoral man intensely self-loathing yet devoted to his task of defrauding people of their money. The pardoner makes people believe that they have sinned and need to buy pardons to save themselves from eternal damnation. The Pardoner tells a tail about three rioters who encounter death through their greediness. His motive for telling his tale is to get the travelers to buy pardons from him. This once again voices Chaucers distrust toward the church. Furthermore Chaucer at...

Vlsi Implementation of Array Based Fir Filter Folding Essays

Vlsi Implementation of Array Based Fir Filter Folding Essays Vlsi Implementation of Array Based Fir Filter Folding Essay Vlsi Implementation of Array Based Fir Filter Folding Essay We are grateful to our Principal, Prof. K. Venkataramani for his support and direction in the course of the project. We take great pleasure in thanking our Head of the Department, Dr. S. Jayashri who has always been a source of inspiration. Her constant motivation has been a driving force for the successful completion of the project. This project was made possible due to the proficient and prompt guidance given by our Project Guide, Mr. J. Selvakumar. We take this opportunity to express our gratitude for the encouragement he has provided us. We are indebted to him for spending his valuable time with us.We thank our project coordinator, Mrs. M. Susila for conducting periodic reviews and giving us valuable suggestions. We also thank the lab technicians for their help and cooperation. ABSTRACT This project aims to implement finite impulse response (FIR) filter based on multiplier arrays in Very Large Scale Integration (VLSI) and intends to show the reduction of the hardware complexity t hat result out of folding techniques. FIR filter being one of the fundamental components of digital signal processing (DSP) has a vital role to play in communication and signal processing.The advantages of FIR filter are stability and easy implementation but these are undermined by its hardware complexity due to large number of filter-taps. Thus, processes such as folding are used to reduce the hardware complexity of FIR filters because they involve repetitive multiplications. This project deals with the implementation of an 8 tap FIR filter in unfolded, folded and two-stage cascaded folded filter. Cascading combines the merits of folded and unfolded schemes. The filters are implemented with four multipliers- Braun array, Ripple carry, carry save and Wallace tree.The performance of the structures with the four multipliers is compared in terms of hardware complexity and combinational path delay. The advantages of VLSI such as low cost, low power, high reliability, small size and high functionality are to be exploited in this project. The hardware descriptive language used is verilog HDL. TABLE OF CONTENTS CHAPTER NO. TITLE PAGE NO. ABSTRACT LIST OF TABLES LIST OF FIGURES LIST OF SYMBOLS AND ABBREVIATIONS iv x xi xiii 1. INTRODUCTION 1 1. 1 DIGITAL SIGNAL PROCESSING 1. 1. 1 Analog and digital signals 1. 1. 2 Signal processing 1. 1. 3 Digital signal processors 1. 1. Applications of DSP 1 1 1 2 2 2. LITERATURE OVERVIEW 2. 1 2. 2 2. 3 FILTERS ANALOG FILTERS DIGITAL FILTERS 2. 3. 1 Advantages of digital filter 2. 3. 2 Operation of digital filter 2. 3. 3 FIR and IIR filters 2. 3. 4 FIR filter 2. 3. 4. 1 Terms used in FIR filter 4 4 4 4 5 6 7 7 7 2. 3. 4. 2 Advantages of FIR filter 2. 3. 4. 3 Disadvantages of FIR filter 2. 4 FOLDING 8 9 9 3. ARCHITECTURES OF FIR FILTER 10 3. 1 3. 2 UNFOLDED ARCHITECTURE FOLDED ARCHITECTURE OF K TAP FIR FILTER 10 11 3. 3 CASCADED ARCHITECTURE OF FIR FILTER 13 4. MULTIPLIERS 4. 1 4. 2 BASICS OF DIGITAL MULTIPLICATION ARRAY MULTIPLIER 4. . 1 Braun array multiplier 4. 2. 2 Ripple carry multiplier 4. 2. 3 Carry save multiplier 4. 3 TREE MULTIPLIER 4. 3. 1 Wallace tree multiplier 16 16 16 17 18 19 20 20 5. SOURCE CODE 5. 1 UNFOLDED FILTER 5. 1. 1 Top module 5. 1. 2 16 bit adder 5. 1. 3 17 bit adder 5. 1. 4 18 bit adder 5. 1. 5 D flip flop 5. 1. 6 Multiplier 5. 2 FOLDED FILTER 5. 2. 1 Top module 5. 2. 2 Adder module 5. 2. 3 D-R module 5. 2. 4 D flip flop 22 22 22 23 23 23 23 24 24 24 25 25 26 5. 2. 5 Multiplier adder unit 5. 2. 6 Multiplier 5. 2. 7 Multiplexer 5. 2. 8 C-R module 5. 3 CASCADED FIR FILTER 5. 3. 1 Top module 5. 3. Adder module 5. 3. 3 D-R module 5. 3. 4 D flip flop 5. 3. 5 Filter stage 1 26 27 28 28 28 28 29 29 29 30 31 32 33 34 34 35 35 35 36 37 39 40 40 40 5. 3. 6 Filter stage 2 5. 3. 7 Multiplier adder unit 1 5. 3. 8 Multiplier adder unit 2 5. 3. 9 Multiplier 5. 3. 10 Multiplexer 5. 3. 11 C-R module 5. 4 MULTIPLIERS 5. 4. 1 Braun array multiplier 5. 4. 2 Carry save multiplier 5. 4. 3 Ripple carry multi plier 5. 4. 4 Wallace tree multiplier 5. 5 ADDERS 5. 5. 1 Full adder 5. 5. 2 Half adder 6. SIMULATION RESULTS 6. 1 6. 2 6. 3 UNFOLDED FOLDED CASCADED 41 41 42 43 7. XILINX SYNTEHSIS AND POWER REPORT: 7. UNFOLDED FIR FILTER 7. 1. 1 Synthesis report 7. 1. 2 Power report 44 44 44 46 7. 2 FOLDED FIR FILTER WITH BRAUN ARRAY MULTIPLIER 7. 2. 1 Synthesis report 7. 2. 2 Power report 47 47 49 7. 3 FOLDED FIR FILTER WITH CARRY SAVE MULTIPLIER 7. 3. 1 Synthesis report 7. 3. 2 Power report 49 49 52 7. 4 FOLDED FIR FILTER WITH RIPPLE CARRY MULTIPLIER 7. 4. 1 Synthesis report 7. 4. 2 Power report 52 52 54 7. 5 FOLDED FIR FILTER WITH WALLACE TREE MULTIPLIER 7. 5. 1 Synthesis report 7. 5. 2 Power report 55 55 57 7. 6 CASCADED FIR FILTER WITH BRAUN ARRAY MULTIPLIER 7. 6. 1 Synthesis report 7. 6. 2 Power report 58 58 60 . 7 CASCADED FIR FILTER WITH CARRY SAVE MULTIPLIER 7. 7. 1 Synthesis report 7. 7. 2 Power report 60 60 63 7. 8 CASCADED FIR FILTER WITH RIPPLE CARRY MULTIPLIER 7. 8. 1 Synthesis repor t 7. 8. 2 Power report 63 63 66 7. 9 FOLDED FIR FILTER WITH WALLACE TREE MULTIPLIER 7. 9. 1 Synthesis report 7. 9. 2 Power report 66 66 68 8. RTL SCHEMATICS 8. 1 8. 2 8. 3 UNFOLDED FIR FILTER FOLDED FIR FILTER CASCADED FIR FILTER 70 70 71 71 9. FPGA EDITOR DIAGRAMS: 9. 1 9. 2 9. 3 UNFOLDED FIR FILTER FOLDED FIR FILTER CASCADED FIR FILTER 72 72 73 74 10. COMPARISON 10. 1 COMPARISON OF MULTIPLIERS 10. 1. 1 Charts 10. COMPARISON OF THE THREE ARCHITECTURES OF FIR FILTER 10. 2. 1 Charts 10. 2. 2 Tables 75 75 75 76 76 77 11. CONCLUSION AND FUTURE ENHANCEMENTS 79 APPENDICES A B XILINX SPARTAN II FPGA FAMILY VERILOG 80 80 84 REFERENCES 87 LIST OF TABLES: S. NO TABLE TITLE PAGE NO 1. Table10. 1. Comparison of the gate count of architectures 77 2. Table10. 2. Comparison of the different structures 78 3. Table10. 3. Comparison of the gate count of the structures with different multipliers 78 LIST OF FIGURES: S. NO FIGURE TITLE PAGE NO 1. Fig2. 1. Filtering operation 4 2. Fig2. 2. Signal Proces sing system 5 . Fig2. 3. FIR filter 7 4. Fig3. 1. FIR filter in direct form 10 5. Fig3. 2. Folded architecture of k tap FIR filter 12 6. 7. Fig3. 3. Fig3. 4. Timing diagram 8-tap direct form FIR filter divided into two filter stages 12 13 8. Fig3. 5. Cascaded structure of two folded filter stages 14 9. Fig3. 6. Timing diagram 15 10. Fig4. 1. Multiplier cell 16 11. Fig4. 2. Braun Array Multiplier 17 12. Fig4. 3. Ripple Carry Array multiplier 18 13. Fig4. 5 Carry Save Array Multiplier 19 14. Fig4. 6. Flowchart of a tree multiplier 20 15. Fig4. 7. Transforming a partial product tree into a wallace tree 1 16. Fig4. 8. Wallace tree multiplier 21 17. Fig6. 1. Model Sim Output of unfolded FIR filter 41 18. Fig6. 2. Model Sim Output of folded FIR filter 42 19. Fig6. 3. Model Sim Output of cascaded FIR filter 43 20. 21. Fig 7. 1. Fig8. 1. Project properties RTL schematic of unfolded FIR filter 44 70 22. Fig8. 2. RTL schematic of folded FIR filter 71 23. Fig8. 3. RTL schematic of cascaded FIR filter 71 24. Fig9. 1 Fpga editor diagram of unfolded fir filter 72 25. Fig9. 2 Fpga editor diagram of folded fir filter 73 26. Fig9. 3 Fpga editor diagram of cascaded fir filter 74 27. Fig10. 1Combinational delay of the multipliers 75 28. Fig10. 2 Hardware complexity of the multipliers 75 29. Fig10. 3 Hardware complexity of the three architectures of fir filter 76 30. Fig10. 4 No of clock cycles to obtain output 76 31. Fig10. 5 Combinational delay 77 32. Fig10. 6 No of slices 77 LIST OF SYMBOLS AND ABBREVIATIONS: ADC : Analog to Digital Converter ALU : Arithmetic and Logic Unit ASIC : Application Specific Integrated Circuit BAM : Braun Array Multiplier CSM : Carry Save Multiplier DAC : Digital To Analog converter FA FFT FIR : Full Adder : Fast Fourier Transform : Finite Impulse ResponseFPGA : Field Programmable Gate Arrays GCLK : Global Clock HA : Half Adder HDL : Hardware Descriptive Language IEEE : Institute of Electrical and Electronics Engineers IIR IOB LSB : Infinite Impulse Response : Input Output Buffer : Least Significant Bit LUT : Look Up Table MAC : Multiply Accumulate MSB : Most Significant Bit RCM : Ripple Carry Multiplier RTL : Register Transfer Level VHDL : VHSIC Hardware Descriptive Language VLSI : Very Large Scale Integration 1. INTRODUCTION: 1. 1 DIGITAL SIGNAL PROCESSING: Digital Signal Processing, as the term suggests, is the processing of signals by digital means.A signal in this context can mean a number of different things. Historically the origins of signal processing are in electrical engineering, and a signal here means an electrical signal carried by a wire or telephone line, or perhaps by a radio wave. More generally, however, a signal is a stream of information representing anything from stock prices to data from a remote-sensing satellite. The term digital comes from digit, meaning a number (you count with your fingers your digits), so digital literally means numerical; the French word for digital is ‘numerique’.A d igital signal consists of a stream of numbers, usually (but not necessarily) in binary form. The processing of a digital signal is done by performing numerical calculations. 1. 1. 1 ANALOG AND DIGITAL SIGNALS: In many cases, the signal of interest is initially in the form of an analog electrical voltage or current, produced for example by a microphone or some other type of transducer. In some situations, such as the output from the readout system of a CD (compact disc) player, the data is already in digital form.An analog signal must be converted into digital form before DSP techniques can be applied. An analog electrical voltage signal, for example, can be digitized using an electronic circuit called an analog-to-digital converter or ADC. This generates a digital output as a stream of binary numbers whose values represent the electrical voltage input to the device at each sampling instant. 1. 1. 2 SIGNAL PROCESSING: Signals commonly need to be processed in a variety of ways. For ex ample, the output signal from a transducer may well be contaminated with unwanted electrical noise.The electrodes attached to a patients chest when an ECG is taken measure tiny electrical voltage changes due to the activity of the heart and other muscles. The signal is often strongly affected by mains pickup due to electrical interference from the mains supply. Processing the signal using a filter circuit can remove or at least reduce the unwanted part of the signal. Increasingly nowadays, the filtering of signals to improve signal quality or to extract important information is done by DSP techniques rather than by analog electronics.The development of digital signal processing dates from the 1960s with the use of mainframe digital computers for number-crunching applications such as the Fast Fourier Transform (FFT), which allows the frequency spectrum of a signal to be computed rapidly. These techniques were not widely used at that time, because suitable computing equipment was gene rally available only in universities and other scientific research institutions. 1. 1. 3 DIGITAL SIGNAL PROCESSORS: The introduction of the microprocessor in the late 1970s and early 1980s made it possible for DSP techniques to be used in a much wider range of applications.However, general-purpose microprocessors such as the Intel x86 family are not ideally suited to the numerically-intensive requirements of DSP, and during the 1980s the increasing importance of DSP led several major electronics manufacturers (such as Texas Instruments, Analog Devices and Motorola) to develop Digital Signal Processor chips specialized microprocessors with architectures designed specifically for the types of operations required in digital signal processing. Like a general-purpose microprocessor, a Digital Signal Processor is a programmable device, with its own native instruction code.DSP chips are capable of carrying out millions of floating point operations per second, and like their better-known g eneral-purpose cousins, faster and more powerful versions are continually being introduced. DSPs can also be embedded within complex system-on-chip devices, often containing both analog and digital circuitry. 1. 1. 4 APPLICATIONS OF DSP: DSP technology is nowadays commonplace in such devices as mobile phones, multimedia computers, video recorders, CD players, hard disc drive controllers and modems, and will soon replace analog circuitry in TV sets and telephones.An important application of DSP is in signal compression and decompression. Signal compression is used in digital cellular phones to allow a greater number of calls to be handled simultaneously within each local cell. DSP signal compression technology allows people not only to talk to one another but also to see one another on their computer screens, using small video cameras mounted on the computer monitors, with only a conventional telephone line linking them together. In audio CD systems, DSP technology is used to perform complex error detection and correction on the raw data as it is read from the CD.Although some of the mathematical theory underlying DSP techniques, such as Fourier and Hilbert Transforms, digital filter design and signal compression, can be fairly complex, the numerical operations required actually to implement these techniques are very simple, consisting mainly of operations that could be done on a cheap four-function calculator. The architecture of a DSP chip is designed to carry out such operations incredibly fast, processing hundreds of millions of samples very second, to provide real-time performance: that is, the ability to process a signal live as it is sampled and then output the processed signal, for example to a loudspeaker or video display. All of the practical examples of DSP applications mentioned earlier, such as hard disc drives and mobile phones, demand real-time operation. The major electronics manufacturers have invested heavily in DSP technology. Because they no w find application in mass-market products, DSP chips account for a substantial proportion of the world market for electronic devices.Sales amount to billions of dollars annually, and seem likely to continue to increase rapidly. 2. LITERATURE OVERVIEW: 2. 1 FILTERS: In signal processing, the function of a filter is to remove unwanted parts of the signal, such as random noise, or to extract useful parts of the signal, such as the components lying within a certain frequency range. The following block diagram illustrates the basic idea. Fig2. 1. Filtering operation There are two main kinds of filter, analog and digital. They are quite different in their physical makeup and in how they work. 2. ANALOG FILTERS: An analog filter uses analog electronic circuits made up from components such as resistors, capacitors and op amps to produce the required filtering effect. Such filter circuits are widely used in such applications as noise reduction, video signal enhancement, graphic equalizers i n hi-fi systems, and many other areas. There are well-established standard techniques for designing an analog filter circuit for a given requirement. At all stages, the signal being filtered is an electrical voltage or current, which is the direct analogue of the physical quantity (e. . a sound or video signal or transducer output) involved. 2. 3 DIGITAL FILTER: A digital filter is any electronic filter that works by performing digital math operations on an intermediate form of a signal. This is in contrast with older analog filters which work entirely in the analog realm and must rely on physical networks of electronic components (such as resistors, capacitors, transistors, etc. ) to achieve a desired filtering effect. Digital filters can achieve virtually any filtering effect that can be expressed as a mathematical algorithm. The two primary limitations of igital filters are their speed (the filter cant operate any faster than the computer at the heart of the filter), and their co st. However as the cost of integrated circuits have continued to drop over time, digital filters have become increasingly commonplace and are now an essential element of many everyday objects such as radios, cellphones, and stereo receivers. The analog input signal must first be sampled and digitized using an ADC (analog to digital converter). The resulting binary numbers, representing successive sampled values of the input signal, are transferred to the processor, which carries out numerical calculations on them.These calculations typically involve multiplying the input values by constants and adding the products together. If necessary, the results of these calculations, which now represent sampled values of the filtered signal, are output through a DAC (digital to analog converter) to convert the signal back to analog form. Note that in a digital filter, the signal is represented by a sequence of numbers, rather than a voltage or current. Fig2. 2 Signal processing system 2. 3. 1 A DVANTAGES OF DIGITAL FILTERS: The following list gives some of the main advantages of digital over analog filters. A digital filter is programmable, i. . its operation is determined by a program stored in the processors memory. This means the digital filter can easily be changed without affecting the circuitry (hardware). Redesigning the filter circuit can only change an analog filter. Digital filters are easily designed, tested and implemented on a general-purpose computer or workstation. The characteristics of analog filter circuits (particularly those containing active components) are subject to drift and are dependent on temperature. Digital filters do not suffer from these problems, and so are extremely stable with respect both to time and temperature.Unlike their analog counterparts, digital filters can handle low frequency signals accurately. As the speed of DSP technology continues to increase, digital filters are being applied to high frequency signals in the RF (radio freq uency) domain, which in the past was the exclusive preserve of analog technology. Digital filters are very much more versatile in their ability to process signals in a variety of ways; this includes the ability of some types of digital filter to adapt to changes in the characteristics of the signal. 2. 3. OPERATION OF DIGITAL FILTERS: Suppose the raw signal, which is to be digitally filtered, is in the form of a voltage waveform described by the function V = x (t) where t is time. This signal is sampled at time intervals h (the sampling interval). The sampled value at time t = ih is xi = x (ih) Thus the digital values transferred from the ADC to the processor can be represented by the sequence x0, x1, x2, x3, Corresponding to the values of the signal waveform at times t = 0, h, 2h, 3h, (where t = 0 is the instant at which sampling begins).At time t = nh (where n is some positive integer), the values available to the processor, stored in memory, are x0, x1, x2, x3, , xn Note that the sampled values xn+1, xn+2 etc. are not available, as they havent happened yet! The digital output from the processor to the DAC consists of the sequence of values y0, y1, y2, y3, , yn In general, the value of yn is calculated from the values x0, x1, x2, x3, , xn. The way in which the ys are calculated from the xs determines the filtering action of the digital filter. 2. 3. FIR AND IIR FILTERS: The impulse response of a digital filter is the output sequence from the filter when a unit impulse is applied at its input. (A unit impulse is a very simple input sequence consisting of a single value of 1 at time t = 0, followed by zeros at all subsequent sampling instants). An FIR filter is one whose impulse response is of finite duration. An IIR filter is one whose impulse response (theoretically) continues forever, because the recursive (previous output) terms feed back energy into the filter input and keep it going.Impulse Response The impulse response of a FIR filter is actually just the set of FIR coefficients. (If you put an impulse into a FIR filter which consists of a 1 sample followed by many 0 samples, the output of the filter will be the set of coefficients, as the 1 sample moves past each coefficient in turn to form the output. ) The term IIR is not very accurate, because the actual impulse responses of nearly all IIR filters reduce virtually to zero in a finite time. 2. 3. 4 FIRFILTER: Fig2. 3. FIR filter 2. 3. 4. 1 TERMS USED IN DESCRIBING FIR FILTERS: Tap A FIR tap is simply a coefficient/delay pair.The number of FIR taps, (often designated as N) is an indication of 1) the amount of memory required to implement the filter, 2) the number of calculations required, and 3) the amount of filtering the filter can do; in effect, more taps means more stop band attenuation, less ripple, narrower filters, etc. ) Multiply-Accumulate (MAC) In a FIR context, a MAC is the operation of multiplying a coefficient by the corresponding delayed data sample and acc umulating the result. FIRs usually require one MAC per tap. Most DSP microprocessors implement the MAC operation in a single instruction cycle.Transition Band The band of frequencies between pass band and stop band edges. The narrower the transition band, the more taps are required to implement the filter. (A small transition band results in a sharp filter. ) Delay Line The set of memory elements that implement the Z^-1 delay elements of the FIR calculation. Circular Buffer A special buffer which is circular because incrementing at the end causes it to wrap around to the beginning, or because decrementing from the beginning causes it to wrap around to the end.Circular buffers are often provided by DSP microprocessors to implement the movement of the samples through the FIR delay-line without having to literally move the data in memory. When a new sample is added to the buffer, it automatically replaces the oldest one. 2. 3. 4. 2 ADVANTAGES OF FIR FILTERS: Compared to IIR filters, FIR filters offer the following advantages: They can easily be designed to be linear phase (and usually are). Put simply, linear-phase filters delay the input signal, but don’t distort its phase. They are simple to implement.On most DSP microprocessors, the FIR calculation can be done by looping a single instruction. They are suited to multi-rate applications. By multi-rate, we mean decimation (reducing the sampling rate), interpolation (increasing the sampling rate), or both. Whether decimating or interpolating, the use of FIR filters allows some of the calculations to be omitted, thus providing an important computational efficiency. In contrast, if IIR filters are used, each output must be individually calculated, even if it that output will be discarded (so the feedback will be incorporated into the filter).They have desirable numeric properties. In practice, all DSP filters must be implemented using finite-precision arithmetic, that is, a limited number of bits. The use of finiteprecision arithmetic in IIR filters can cause significant problems due to the use of feedback, but FIR filters have no feedback, so they can usually be implemented using fewer bits, and the designer has fewer practical problems to solve related to non-ideal arithmetic. They can be implemented using fractional arithmetic. Unlike IIR filters, it is always possible to implement a FIR filter using coefficients with magnitude of less than 1. . (The overall gain of the FIR filter can be adjusted at its output, if desired. ) This is an important consideration when using fixed-point DSPs, because it makes the implementation much simpler. FIR filters inherently stable. Since hey have no feedback elements, any bounded input results in a bounded output. 2. 3. 4. 3 DISADVANTAGES OF FIR FILTERS: Compared to IIR filters, FIR filters sometimes have the disadvantage that they require more memory and/or calculation to achieve a given filter response characteristic. Also, certain responses a re not practical to implement with FIR filters 2. FOLDING: Folding transformation is used to systematically determine the control circuits in DSP architectures where multiple algorithm operations such as addition operations are time-multiplexed to a single functional unit. Thus the number of functional units in the implementation is reduced resulting in an IC with low silicon area. This is an important aspect in synthesizing DSP architectures. In general, folding can be used to reduce the number of hardware functional units by a factor of N at the expense of increasing the computational time by a factor of N (number of algorithm operations executed on a single functional unit in hardware).Folding transformation may also lead to an architecture that uses a large number of registers. To overcome this drawback, techniques can be used to compute the minimum number of registers required to implement a folded DSP architecture and to allocate data to these registers. Using register minimiz ation techniques along with the folding transformation not only reduces the number of functional units but also keeps the area consumed by memory in the folded architecture to a minimum. 3. ARCHITECTURES OF FIR FILTER: The direct form structure consists of a large number of filter taps that lead to excessive hardware complexity.Folding techniques have been proposed as a means of reducing the hardware complexity when the processing throughput required by the application is less than the throughput at which the circuit can operate. FIR filters are ideal candidates for folding since they are essentially a repetition of multiplications. The main drawback of folded FIR filter scheme is that while they achieve significant hardware reduction, they also reduce the sample rate. A way to combine the merits of folded and unfolded filters is to cascade a number of folded FIR filter units.The partially folded filter is an intermediate form between the folded and unfolded form of a filter, featur ing higher throughput than the folded and requiring less hardware than the unfolded. Partially folded filter consists of a number of modules, each of them being a fully folded filter. Cascading p such modules increases the sample rate by p. 3. 1 DIRECT FORM ARCHITECTURE: The unfolded architecture consists of delays, multipliers and adders. The output is obtained every clock cycle. A k-tap filter consists of k multipliers, k-1 adders and k-1 delays.The input sample x is delayed and multiplied with filter coefficients and accumulated to get the output. Fig4. shows a k-tap direct FIR filter. Fig3. 1. FIR filter in direct form 3. 2 FOLDED ARCHITECTURE OF K-TAP FIR FILTER: The folded architecture consists of a multiplier and adder unit, which performs one multiplication, addition operation every clock cycle. So it requires k-clock cycles to perform k such operations in production of single output of a k-tap filter. The cyclic shift registers C-R store the filter coefficients in the desce nding order and k-1 input samples are stored in the D-R cyclic shift registers in the descending order.These shift registers account for the delay elements present in the direct form of the unfolded architecture of an FIR filter. The C-R registers correspond to the data latches where the filter coefficients are stored when the filter is programmed. Fig5. shows the architecture of the folded FIR filter. The convolution output is produced in k-clock cycles. The term x (n-k-1) hk-1 is computed first and the term x(n)h0 is computed last. The multiplexer set; mux1 is used to input the filter coefficients to the multiplier-add unit (mac).The select signal ‘sel’ is used to select between the two inputs, one being the external input ‘hc’ and the other is the data out of the shift register C-R. During the first k clock cycles hc is selected and for the remaining computations output from C-R is selected. Multiplexer set, mux2 is used to obtain a new input every kth c lock cycle which then gets stored in the D-R shift register. The third multiplexer set, mux3 is used to obtain the sum of products through accumulation in the mac unit and to clear the accumulator every kth clock cycle. The select signal for the second and the third multiplexer sets is ‘s’.The signal ‘s’ is made high every kth clock cycle. Tristate buffers, which are enabled by signal ‘s’, are used to obtain the final output. The circuit operates at clock frequency ‘fc’. An input sample is processed every k clock cycles and therefore the filter operation frequency is fs=fc/k. The frequency of the control signal ‘s’ is ‘fs’. Fig6. shows the timing diagram of the operation. Fig3. 2. Folded architecture of k-tap FIR filter Fig3. 3. Timing diagram 3. 3 CASCADED ARCHITECTURE OF FIR FILTER: A cascaded structure is obtained by dividing the k-tap filter into many stages. Fig7. hows a twostage structure obtained by dividing an 8-tap FIR filter and introducing a delay between the two stages. Each stage is partially folded and cascaded. Fig8. shows the cascaded architecture using two folded FIR filters in direct form. The first four filter coefficients are stored in the C-R register of stage 1 and the next four coefficients are stored in the C-R register of stage 2. The input sample to the second stage comes from the delay register D-R. The output of the second stage ‘yp’ is used to initialize the accumulator of the first stage. The final output ‘y’ is obtained from the first stage.A delay exists in the sum line from the output of stage 2 to the input of the adder of stage 1 in the Fig. 3. This corresponds to the delay in the input of adder of stage 1 in Fig4. The operation of each stage is similar to that of a normal folded FIR filter. The select signal ‘s’ of both the stages are synchronized. The select signal ‘sel’ to the multiplexer set, m ux1 is used to select the output of the C-R register after four clock cycles as only four coefficients are used by each stage. The second stage produces a partial output ‘yp’ in one sample cycle, which is used by the first stage in the next sample cycle.Fig3. 4. 8-tap direct form FIR filter divided into two filter stages Fig8. Cascaded structure of two folded filter stages The timing diagram, shown in Fig9. clarifies the operation of the circuit. In this diagram y(n), yp(n) and the filter terms accumulated after every clock cycle by both stages is shown. The Computation of the result y(n) lasts to x(n) sample cycles. During the first cycle, stage 2 computes yp(n). This is available in the last clock cycle and is used as an initial value for the accumulation performed by stage 1 in the second sample cycle.During this cycle stage 1 computes y(n) and stage2 computes yp(n+1) of the next result. Thus the computations of two results y(n) and yp(n+1) are overlapped and we obta in a result every four clock cycles. The select signal ‘s’ is made high every fourth clock cycle to get the output. Fig3. 5. Timing diagram 4. MULTIPLIERS: The most critical function carried out by ALU is multiplication Digital multiplication is not the most fundamentally complex operation, but is the most extensively used operation (especially in signal processing) Innumerable schemes have been proposed for realization of the operation 4. BASICS OF DIGITAL MULTIPLICATION: Digital multiplication entails a sequence of additions carried out on partial products The method by which this partial product array is summed to give the final product is the key distinguishing factor amongst the numerous multiplication schemes A 4. 2 ARRAY MULTIPLIER: Partial products are independently computed in parallel Consider two binary numbers A and B, of m and n bits, respectively: Pk is known as the partial product term, also called the summand. Fig4. 1. Multiplier cell 4. 2. 1 BRAUN ARRAY MULTIPLIER: Simplest parallel multiplier. Suited only for positive operands.The partial products are computed in parallel and then collected through a series of carry save adders. The completion time is limited by the depth of the carry save and by the carry propagation in the adder. Fig4. 2. Braun array multiplier 4. 2. 2 RIPPLE CARRY ARRAY MULTIPLIERS: Row ripple form Unrolled shift-add algorithm Delay is proportional to N A ripple carry array multiplier (also called row ripple form) is an unrolled embodiment of the classic shift-add multiplication algorithm. The illustration shows the adder structure used to combine all the bit products in a 44 multiplier.The bit products are the logical and of the bits from each input. They are shown in the form x, y in the drawing. The maximum delay is the path from either LSB input to the MSB of the product, and is the same (ignoring routing delays) regardless of the path taken. The delay is approximately 2*n. Fig4. 3. Ripple carry array mult iplier 4. 2. 3 CARRY SAVE ARRAY MULTIPLIERS: Column ripple form Fundamentally same delay and gate count as row ripple form Gate level speed ups available for ASICs Ripple adder can be replaced with faster carry tree adder Regular routing patternFig4. 5. Carry save array multiplier 4. 3 TREE MULTIPLIER: Offers potential for multiplication in time O (logn) Once partial product array is formed, bits are passed to reduction network Here column-wise compression of the bits takes place, yielding two final partial products Final product is obtained by addition of these two partial products Considered to be irregular in form and does not permit efficient VLSI realization Fig4. 6. Flowchart of a tree multiplier 4. 3. 1 WALLACE TREE MULTIPLIER: Partial Sum adders can be re-arranged in a ree-like fashion, reducing the critical path and the number of cells needed. Fig. (a) Only column 3 has to add 4 bits. All others are less complex Fig. (b) Half Adders (HA) in column 3 ; 4. Fig. (c) Full Adder s (FA) in column 3, 4, and 5; HA in column 2. Fig. (d) Finally, HA from column 1 to 6. Fig4. 7. Transforming a partial product tree into a wallace tree Wallace Tree multiplier implementation. Substantial saving on larger multiplier. Fig4. 8. Wallace tree multiplier 5. SOURCE CODE: 5. 1 UNFOLDED FIR FILTER: 5. 1. TOP MODULE: module FIR_filter(x,h0,h1,h2,h3, h4,h5,h6,h7,clk,y); input[7:0]x,h0,h1,h2,h3,h4,h5,h6,h7; input clk; output[18:0]y; wire[7:0]x0,x1,x2,x3,x4,x5,x6,x7; wire[7:0]x0_bar,x1_bar,x2_bar,x3_bar,x4_bar,x5_bar,x6_bar,x7_bar; wire [15:0]p0,p1,p2,p3,p4,p5,p6,p7; wire[16:0]s0,s1,s2,s3; wire[17:0]s4,s5; delay d0(x,clk,reset,x0,x0_bar); delay d1(x0,clk,reset,x1,x1_bar); delay d2(x1,clk,reset,x2,x2_bar); delay d3(x2,clk,reset,x3,x3_bar); delay d4(x3,clk,reset,x4,x4_bar); delay d5(x4,clk,reset,x5,x5_bar); delay d6(x5,clk,reset,x6,x6_bar); delay d7(x6,clk,reset,x7,x7_bar); mul_8x8 m0(x0,h0,p0); mul_8x8 m1(x1,h1,p1); mul_8x8 m2(x2,h2,p2); mul_8x8 m3(x3,h3,p3); mul_8x8 m4(x4,h4,p4) ; mul_8x8 m5(x5,h5,p5); mul_8x8 m6(x6,h6,p6); mul_8x8 m7(x7,h7,p7); adder_16bit a0(p0,p1,s0), a1(p2,p3,s1), a2(p4,p5,s2), a3(p6,p7,s3); adder_17bit a4(s0,s1,s4), a5(s2,s3,s5); adder_18bit a6(s4,s5,y); endmodule 5. 1. 2 16-BIT ADDER: module adder_16bit(A,B,sum); input [15:0] A,B; output [16:0]sum; assign sum=A+B; endmodule 5. 1. 3 17-BIT ADDER: module adder_17bit(A,B,sum); input[16:0]A,B; input[17:0]sum; assign sum=A+B; endmodule 5. 1. 4 18-BIT ADDER: module adder_18bit(A,B,sum); input[17:0]A,B; output[18:0]sum; assign sum=A+B; endmodule 5. 1. 5 D FLIPFLOP: module delay(D,CLK,reset,Q,Q_bar); input [7:0] D; input CLK,reset; output[7:0] Q; output[7:0]Q_bar; reg [7:0] Q; assign Q_bar=~Q; always @(posedge CLK or negedge reset) if(reset==0)Q

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