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A 66-year-old female presents to emergency department feeling generally unwell for the past week, associated with dizziness on standing and central chest/epigastric pain radiating to the shoulders. The patient also reported intermittent palpitations and chest pain for the past week. The patient described the pain as ‘heartburn’ across her chest and denied any history of radiation to the left arm or jaw and dyspnoea. The patient experienced the most severe episode this morning soon after waking, and felt light-headed, with palpitations and chest discomfort. Her past medical history included hypertension controlled with 10mg Amlodipine and 50mg Atenolol once daily, as well as 10mg Atorvastatin once daily. She was a non-smoker, had an alcohol intake of 4 units weekly, and was independent with normal mobility.
Get original essayOn physical examination, the patient was in no obvious distress and looked comfortable. She had warm extremities and was well perfused, with a blood pressure of 112/68mmHg and pulse of 68 beats per minute (BPM), cardiovascular, respiratory and abdominal examinations were unremarkable. Her Electrocardiogram (ECG) on admission showed an HR 132, with narrow QRS complexes and no p waves, consistent with a diagnosis of fast atrial fibrillation (AF). Prior to discharge, her repeat ECG showed normal sinus rhythm. The patient was diagnosed with the new onset of AF and was treated with Rivaroxaban 20mg OD, Bisoprolol 10mg OD, and amiodarone 200mg OD and 400mg TDS.
After finding this case study I was interested to learn more about the different approaches to treating AF how a decision is made regarding rate vs. rhythm control I began to do my own research on how the rate controlling drug works, why rhythm control drug was not appropriate in this patient, and the other treatments available to patients with AF. In this essay, I will give a brief overview of AF, with a focus on the different treatments that are used to control patients with AF and which treatment is more significant for the patient in the long-term.
AF is the most common sustained cardiac arrhythmia; it can cause a range of symptoms from dyspnoea to chest pain and palpitations, which can impair quality of life without treatment. It is prevalent in the population in people over 50 and is usually uncommon in infants unless structural or functional abnormality. It has been calculated that in the year 2000 the NHS had spent a total of £459 million including drug treatment and hospital admissions having an impact on healthcare. If affected patients do not get appropriate therapeutic intervention it can increase the risk of stroke five-fold. This is one of the more common but extremely serious complications of AF, alongside congestive heart failure and myocardial infarction.
The main focus in the management of AF is to reduce the chances of severe symptoms such as tachycardia-induced cardiomyopathy (TIC) and stroke. The control of heart rate and rhythm are initially important to restore sinus rhythm; however, it is also important to consider the risk of thromboembolism therefore unless contraindicated therapeutic dose of an oral anticoagulant should be commenced. An AF patient should be assessed for both stroke and bleeding risk. The stroke risk is calculated by the used of CHA2DS2-VASc stroke risk score as my patient did not have this risk assessment completed within the patient notes I have worked out the result for the patient and her result would have been 3 points, therefore, my patient is in the moderate-high risk and is a candidate for anticoagulation which my patient was prescribed with Rivaroxaban 20mg OD. Similar to the stroke risk assessment the HAS-BLED scoring assessment the patient's result would be 2 points which state that anticoagulant can be considered, however, the patient does have a moderate risk for a major bleed.
An important factor in determining the management plan is the type of AF the patient has been diagnosed with, there are three different types which are dependent on how long the patient has AF. The first type is paroxysmal AF this occurs spontaneously and lasts less than seven days and doesn’t usually require treatment, persistent AF lasts longer than seven days and requires treatment however sometimes can resolve spontaneously. Finally, the last type is permanent AF which lasts for more than a year and can be usually be controlled with medication or surgery.
The management depends upon the type of AF diagnosed, Currently, AF patients are treated either pharmacologically or non-pharmacologically depending on the type, symptoms, co-morbidities and most importantly how it affects the patient. The treatment is with either a rate or a rhythm controlling drug which both work differently depending on what part of the heart they are placing their effect on. A rate-controlling drug focusses its effect on controlling the ventricular rate, most likely with calcium channel blockers, beta blocker or digoxin. The rhythm controlling drugs are introduced in patients who remain in AF such as amiodarone and sotalol and can use electrical cardioversion to restore sinus rhythm.
Over the last few years, management for AF has dramatically grown and different drugs and procedures have been introduced for both ventricular rate control and rhythm conversion. The initial management of a patient in AF is to haemodynamically stabilise the patient, establish ventricular rate control and to prevent adverse embolic complications. Another goal is termination of AF and possibly restoring sinus rhythm. A significant factor for the patient and clinician when choosing a management plan for an AF patient is whether a patient will benefit from a rate and rhythm control approach. Commonly rate control is the initial management which is simpler than a rhythm control approach to AF, involves less toxic medications and less invasive procedures, compared to rhythm control which uses potential drugs that can have a toxic effect on the patient or an invasive procedure e.g. catheter ablation or surgery however, when rhythmic treatment is successful the patient will restore sinus rhythm. A rate-controlling intervention is mainly used in asymptomatic patients with AF, particularly in patients with recurrent AF the preferred drug is rate control as the initial management.
National Institute and Care Excellence (NICE) (2014) state rate control should be the first line of treatment in newly diagnosed AF, which is the chosen treatment for my patient. A rate control is also used in patients with paroxysmal cause and if the clinicians think that heart failure could be the primary cause. The goal of the ventricular rate control is to attain a rate of less than 100 BPM, by partially blocking signals in the atria and preventing them from being conducted to ventricles by increasing the refractoriness of the AV node resulting in reduced ventricular rate, effectively allowing the heart to pump slower and more efficiently. Medications that are commonly used include beta-blockers or a rate-limiting calcium channel blocker is the first choice and digoxin. NICE recommend monotherapy with a beta-blocker, not sotalol due to its adverse effects, or a rate-limiting calcium-channel blocker as initial therapy as part of a rate controlling intervention. This is independent of a patient’s heart rate, co-morbidities, and personal preference.
Guidelines also state that for patients with non-paroxysmal AF that remain sedentary to consider digoxin monotherapy. If monotherapy does not control the patient’s symptoms and it is thought to be due to poor ventricular control consider combination therapy of two of the following: beta blocker, digoxin and calcium-channel blocker (diltiazem). It is stated by NICE that amiodarone should not be prescribed for long-term rate control.
Rate control medications have some side effects such as fatigue, dyspnoea, pre-syncope and some more serious effects such as inducing a pro-arrhythmia which is more frequent occurrences of pre-existing arrhythmias, also digoxin can be toxic and cause nausea and vomiting initially however if not appropriately treated can cause serious cardiovascular complications. As rate control drugs do not cure AF the patient has to be on a life-long treatment which can cause atrial enlargement due to the increased workload and can increase chances of stroke.
The other type of treatment is rhythm control which is used in symptomatic patients after being trialled with ventricular rate-controlling drugs and being unsuccessful and whose symptoms continue after heart rate has been controlled or for whom a rate control strategy has not been successful.
As AF has been shown to be an independent factor of mortality in AF patient’s research shows that restoring sinus rhythm is more important and delivers a beneficial outcome and decreasing mortality and hospitalisation. There are two main types of rhythm control, cardioversion and drug treatment for restoration of sinus rhythm. The pharmacological drugs commonly used are amiodarone and beta-blockers sotalol, they both work on different ion channels to control the rhythm of the heart. The drug sotalol has an effect by blocking potassium channels to prolong action potentials and refectory periods resulting in slower heart rates. Whereas, amiodarone works by prolonging repolarisation by inhibiting sodium and potassium ion channels resulting in a decrease in heart rate and vascular resistance. The electrical cardioversion is a procedure where electrical currents are delivered to the heart to convert the arrhythmia to sinus rhythm. However, after given the extra cost and potential risks associated with antiarrhythmic drugs patients have been less likely to try this approach. Although amiodarone is usually well tolerated it can cause some common adverse effects such as bradycardia, hyperthyroidism, phototoxicity, slate grey skin, pulmonary toxicity (including pneumonitis and fibrosis), taste disturbance, tremor, and nausea. The other common side effects with sotalol, bradycardia this risk is increased further in patients with severe hypertension, cold extremities, fatigue and visual disturbances.
There has been controversial discussion around rate and rhythm control in treating AF patients, some studies recommend rate control is more beneficial than rhythm control and some suggest rhythm control results have better long-term benefits. There have been many standardised trails to demonstrate the benefit and risks between rate versus rhythm control in AF patients, Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) and Rate Control versus Electrical Cardioversion (RACE) these studies evaluated approaches of rate and rhythm control in AF. Research shows that rate control is a much easier and simpler method for a patient to incorporate into their lives and therefore, a better outcome for the patient as there are more chances for a patient to be compliant with medication, leading to many clinicians ruling out the rhythmic control. Results from the AFFIRM study suggest that beta-blockers had a better success rate of 74% compared to that of 54% in calcium-channel blockers in achieving rate control when they were either used alone or combined with digoxin and therefore, more patients are put on beta-blocker over a calcium channel blocker unless contraindications. Subsequently, the drugs have adverse effects such as exacerbation of asthma and chronic obstructive pulmonary disease (COPD) which can become problematic for younger patients with structural/functional defects or elderly patients who have COPD and causing acute exacerbations and worsening of dyspnoea resulting in emergency hospitalisation. It has also been found to exacerbate depression having a big impact on a patient’s life and unfortunately risks potentially a patient’s mental state, resulting in further healthcare support. This should be taken into consideration when taking a patient history as a physician associate it will be imperative to gain a detailed history from the patient to avoid this issue.
Research has shown that that restoration of sinus rhythm can reduce the risk of emergency hospital admission and stroke, improve the ejection fraction, reduce atrial hypertrophy, and improve exercise capacity, further improving patient’s quality of life, which would have a positive impact on a patient. However, studies show that the use of rhythm control drugs leads to an increased number of hospital admissions due to recurrence of AF. When a rhythmic controlled AF patient requires hospitalisation, a rate controlling drugs are often given intravenously to reduce symptoms during attacks, therefore, patients with rhythmic control and cannot be treated alone they require a combination of both rhythm and rate control. This shows there is dependence on rate control once sinus rhythm has been established previously and shows that there will be cost implications with costlier pharmacological drugs and increased hospital admissions causing a burden on healthcare. Compared to rate control cost both AFFIRM and RACE studies showed that rate control is less costly than rhythm control, making this more favourable due to financial budget restraints.
However, in a selected minority of patients, particularly younger and physically active a rhythm control strategy may be preferred. It has been found that restoring sinus rhythm is more important than a rate control management in persistent AF, AFFIRM supports this by finding reduced mortality rates where there was a control on sinus rhythm and also use of oral anticoagulants, showing a strong correlation in amiodarone restoring sinus rhythm. AFFIRM study shows that within the rhythm controlled group there was an increase by 1-5 fold of a non-cardiovascular death, however, largely driven by increased death from cancer and pulmonary disorders. This marries up with the adverse side effects of increased levels of amiodarone and fibrosis, which may suggest that patients died due to toxic amounts of rhythm control drugs. Although many of the studies suggest there are long-term benefits of restoring and maintaining sinus rhythm such as has improving ejection fraction, reducing left atrial size, allowing AF patients to increase exercise capacity, and improving the quality of life for AF patients, the toxic side effects of rhythm controlling drugs may outweigh the initial benefits in the long-term. In the two largest of these, there was even a trend to increased mortality in the rhythm control group, which may have been due to potential toxicity of drugs and also the inappropriate withdrawal of anti-coagulants in the rhythm control group leading to an increase in thromboembolic events.
As a stroke is one of the most serious adverse events in AF, potentially once the heart was back in sinus rhythm, it should have reduced the risk of stroke and avoid the need for anticoagulation. Unfortunately, this is not always the case and even if the patient is no longer symptomatic, studies show that ECG monitoring shows the presence of asymptomatic incidents often remain, which can make it questionable of the success of restoring sinus rhythm.
RACE studies showed after pooling all the evidence that there was no clear mortality benefit of rhythm control over rate control in patients with asymptomatic AF. RACE also found no substantial significance between rate and rhythm control in patients with AF, although the studies did not include a broad spectrum of patients and excluded younger patients and patients that had severe symptoms the results can only be valid to patients that have no other co-morbidities and patients that were not affecting their daily life and were able to endure their AF only. Showing that these results may not be as valid when deciding a treatment plan for AF patients in other populations, making it an irrelevant source to aid the treatment plan to alleviate the patient’s symptoms and to improve the patient’s long-term outcome.
To conclude as rate control therapy is more important currently compared to a rhythm control therapy because of its advantages for a large percentage of patients with AF, as there is less chance of toxic drug use, reduces the risk of harm to the patient. In my opinion, the studies indicate that unless rate control therapy has been unsuccessful that it less vital to aggressively restore sinus rhythm. I feel this is very important as AF primarily affects 65+ who more than likely have other co-morbidities however, the other important group of patients who can be affected especially younger and physically active individuals and those in whom have congenital defects a rhythm control strategy would be a preferred approach taking into consideration age, other conditions and patients preference.
A future trial should concentrate on the long-term effects of treatment in the largest proportion of patients with AF, those with symptomatic permanent AF, with the aim of improving patient’s quality of life. The inadequate data provides a lack of answers however by completing future trials including a wider range of patients with AF gathering better representation so that the result are applicable to the wider population. To find treatments that are aimed at all groups of people with AF all different age ranges, gender, ethnicities and also different types of AF. NHS England have stated that if treatment for AF is optimised that there is a potential to save £241 million which would be beneficial for both the patient and NHS, by educating general practitioners, implementing diagnostic devices and having pharmacist-run anticoagulation services there has been a reduction in ischaemic events these programmes are being optimised and NHS are encouraging all areas in the country to implement these changes.
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Get custom essayI feel that as a future physician associate I would take a thorough history of a patient to ensure all co-morbidities are discussed and the patient’s preference for how they would like to be treated. In the future I would like to encourage a patient to choose a rhythm controlling therapy, however, until rhythm control therapies are less toxic and have more effective pharmacological drugs for a wider range of patients, it would be ideal to follow NICE on the initial treatment and should remain as rate control in the majority and rhythm in the minority who would benefit. There is more benefit in restoring sinus rhythm in patients who have been diagnosed with AF at a young age and asymptomatic as there are risks associated with prolonged AF which can cause premature death. As a physician associate I would take into account the patients age and conditions and also to educate the patient on the potential risks of prolonged use of rate-controlling drugs and also the toxic effect of the antiarrhythmic drugs however, also state the better long-term outcome for the patient for being in sinus rhythm as this would also decrease chances of the complications that are associated with AF and should be offered both treatments and to be able to make the decision for themselves and take the patients preferences into consideration.
These regions range in size from just a few square meters to thousands of square kilometres. Scattered throughout the earth, several are remnants from the Pleistocene glaciation. Many ponds are seasonal, lasting just a couple of months (such as sessile pools) while lakes may exist for hundreds of years or more. Ponds and lakes may have limited species diversity since they are often isolated from one another and from other water sources like rivers and oceans. Lakes and ponds are divided into three different zones which are usually determined by depth and distance from the shoreline.
Get original essayThese are bodies of flowing water moving in one direction. Streams and rivers can be found everywhere they get their starts at headwaters, which may be springs, snowmelt or even lakes, then travel all the way to their mouths, usually another water channel or the ocean. The characteristics of a river or stream change during the journey from the source to the mouth. The temperature is cooler at the source than it is at the mouth. The water is also clearer, has higher oxygen levels, and freshwater fish such as trout and heterotrophs can be found there. Towards the middle part of the stream or river, the width increases, as does species diversity numerous aquatic green plants and algae can be found. Toward the mouth of the river or stream, the water becomes murky from all the sediments that it has picked up upstream, decreasing the amount of light that can penetrate through the water. Since there is less light, there is less diversity of flora, and because of the lower oxygen levels, fish that require less oxygen, such as catfish and carp, can be found.
Wetlands are areas of standing water that support aquatic plants. Marshes, swamps, and bogs are all considered wetlands. Plant species adapted to the very moist and humid conditions are called hydrophytes. These include pond lilies, cattails, sedges, tamarack, and black spruce. Marsh flora also include such species as cypress and gum. Wetlands have the highest species diversity of all ecosystems. Many species of amphibians, reptiles, birds and furbearers can be found in the wetlands. Wetlands are not considered freshwater ecosystems as there are some, such as salt marshes, that have high salt concentrations. These support different species of animals, such as shrimp, shellfish, and various grasses.
You have to understand the difference between weather and climate before going into the details of climate of the freshwater biomes, weather refers to changing daily atmospheric conditions, while climate refers to weather condition over a certain time period usually a year, Average temperatures in the summer range from 17 to 23 degrees Celsius and 3 to 8 degrees during the winter.
Maintaining freshwater biomes and their climates are important for humans and animals. Most of the water humans drink and use for bathing and other activities comes from freshwater sources. Freshwater biomes also contain diverse flora and fauna, such as algae, that are the basis for rest of the food chain. Plants that thrive in freshwater are a food source for animals and also provide oxygen through photosynthesis, especially in the summer. Freshwater fishes that feed on plants and insects are often a main food source for humans as well. From a human perspective, freshwater biomes not only provide food and water but are also home to thousands of species of fish, animals and plants. Protecting them from climate change helps to secure humans' survival.
Freshwater biomes can develop around creeks, small ponds, rivers and lakes. While often incorrectly associated with marine biomes, these two biomes are actually two separate components of the aquatic biome /water biome. Marine biomes primarily include all the saline water sources in the world, and the freshwater biome, as the word suggests, includes all of the fresh water sources. While marine biomes are much larger than freshwater biomes, both are equally important for the ecosystem.
Intellectual disability (I.D.) is not an uncommon condition and it may be present from birth or childhood. Some significant conditions that are seen in those individuals that have I.D. are lower intellectual functioning than an average person of the same age, having significant delays in developing ones social and communication skills, and their ability to live independently or to care for themselves. Intellectual disability, however, has a wide range of functioning from mild to profound.
Get original essayIntellectual disability is characterised by considerable delays in cognitive, social, practical, and abstract learning skills. Adaptive skills pr the development of adaptive skills may be an issue for those who have I.D. Adaptive skills include such skills as communications skills, personal care skills, social skills, the ability to interact with the community, taking care of one’s health and safety, having leisure activities, performing in school or work. Practical and cognitive tests are used on an individual to classify them as having intellectual disability. Intelligence
The majority of juveniles with below-average IQ scores, in the range of 70 to 89, are not considered to have intellectual disability. Those adolescents that come with mild disability come up to about 85 percent of all cases of intellectual disabilities. They are portrayed as functioning two to four years behind their developmental stage or having an IQ range of 50 to 75. Some of these children with mild disability may not be diagnosed with the condition until they are well into their school years. Those with mild disability are often characterised by their slow development of walking skills, and also talking or communication skills. They are also slower to learn how to feed themselves than most children. However, they are able to learn practical skills such as math and even reading up to the grade six level.
Moderate disability is often characterised by children having IQ in the range from 35 to 49. Children with moderate disability also tend to exhibit development delays in speech skills and also in motor skills. Basic communication skills are able to be learned by those with mild disability and they are also able to learn a few habits that aid their health and safety and they are also able to learn other essential skills in regards to day to day living, however they are usually not likely to obtain academic skills like reading or math.
Out of all the case of intellectual disabilities, 3 to 5 percent of those cases fall under the severe disability category. Diagnoses for those with severe disability often happen at birth or soon after birth while the IQ ranges from 20 to 34. Motor development and communication are difficult for these children to learn. Feeding oneself and bathing oneself, and self-help skills as such are able to be learnt by those with severe disability, however, only with training. Learning how to walk and gaining a general grasp or comprehension of speech comes with age. They can be able to follow daily routines, as adults, and they may be able to perform simple tasks provided that they are directed and live in an environment that is protected.
After severe disability comes profound disability and this level of intellectual disability is characterised by individuals having an IQ of less than 20. Profound disability is often diagnosed at birth. Profound disability is also accountable for 1 to 2 percent of those with I.D.
There are three different types of rocks based on the way they form. Most of the time, they are very easy to tell apart. All three of these rocks come from the rock cycle. These rocks are called Igneous, Metamorphic, and Sedimentary rocks. These rocks are all very different in many ways but they do have one thing in common, they are all made of minerals. Igneous rocks are formed by the cooling and crystallization of magma. Magma is generated in the plastic asthenosphere, a layer of molten rock under the Earth’s crust. There are two types of igneous rock, intrusive and extrusive. Intrusive igneous rock is crystallized below Earth’s surface, and the slow cooling causes large crystals to form. Examples of intrusive igneous rocks are gabbro and granite. Gabbro and granite are very similar but gabbro is dark colored and contains pyroxene and olivine, while granite contains mainly quartz.
Get original essayThe other igneous rock is called Extrusive igneous rocks, they erupt into the surface where they cool quickly and form small crystals. Sometimes they cool so quick they form amorphous glass. These rocks include basalt and obsidian. Basalt is a fine grained, dark colored extrusive igneous rock made mainly of plagioclase and pyroxene. Obsidian is also a dark colored extrusive rock that cools so fast no crystals form. Igneous rocks form at divergent boundaries, subduction zones, convergent boundaries, and hot spots. Igneous rocks compose most of the Earth’s continental crust and nearly all of the oceanic crust.
The second rock in the rock cycle is called Sedimentary rock. Sedimentary rocks form by the accumulation of sediments. There are three types of sedimentary rocks, which include, clastic, chemical, and organic sedimentary rocks. Clastic sedimentary rocks are formed from mechanical weathering debris. Examples of clastic rocks are sandstone and breccia. The second sedimentary rock is called chemical sedimentary rocks. They form when dissolved materials precipitate from solution. Rocks that are apart of chemical sedimentary rocks are iron ore, flint, and limestone. The final sedimentary rock is the organic rock. It forms from the accumulation of plants or animal debris. Just like the chemical sedimentary rock, the organic sedimentary rock also has limestone. Unlike igneous rocks, sedimentary rocks are born cool, mostly underwater. They are arranged in layer of sandy or clay like materials. Some might preserve signs of life like fossils, tracks, or ripple. The main thing about sedimentary rocks is that they don’t change that much when they turn into rock.
The last and final class of rocks is the Metamorphic rock. They are formed when sedimentary and igneous rocks become metamorphosed underground. The main things that make metamorphose rocks are heat, pressure, fluids, and strain. All metamorphic rocks are formed by great heat and pressure. They are almost always strong rocks, made of different minerals, have a wide range of color and luster, and have a striped appearance. Foliated metamorphic rocks are caused when there is high pressure and heat. Rocks that form under these conditions are called schist or gneiss. Non-foliated rocks occur when the is low pressure but high heat. In conclusion all three rocks are important. They all come from the same cycle, the rock cycle, but are all different in their own ways. You can tell the difference between all of them because of their very different characteristics.
The scanner is a device that optically scans images, printed text, handwriting, any object, and which converts it into a digital image. Scanner which are Commonly used in offices are variations of the desktop flatbed scanner where the document is placed on a glass window for Scanning.
Get original essayTypes of scanner
A CCD scanner is composed of a glass pane (or platen), under which there is a bright light (often xenon, LED or cold cathode fluorescent) which illuminates the pane, and a moving optical array in CCD scanning. CCD-type scanners typically contain three rows (arrays) of sensors with red, green, and blue filters.
CIS-Contact Image sensor. This consists of a moving set of red, blue, green LEDs which are strobed for illumination and it is also connected with a monochromatic photodiode array under rod lens array for collection of light .The Images which user needs to be scanned are placed with a face down on the glass and an opaque cover is low-ered over it which will exclude ambient light, and the sensor array and light source will move across the pane and start reading the entire area. Therefore an image is visible to the detector only because of the light it reflects. Transparent images do not work in this way, and require special accessories that il-luminate them from the upper side. Many scanners offerthis as an option.
Uncut film strips of up to six frames, or four mounted slides, are inserted in a carrier, which is then moved by a stepper motor across a lens and CCD sensor inside the scanner. Some models which are mainly used for same-size scans. Film scanners vary a great deal in price and quality. Consumer scanners are relatively inexpensive while the most expensive professional CCD based film scanning system was around 120,000 USD. More expensive solutions are said to produce better results.
This type of scanner are moved over the subject to be imaged with the help of hand. Two different types: 1.document2.3D scanners.
APPSsas1) aaDocument aascanningaxappssw primarily sdesigneda toa handle asdocuments and sdoutput aaPDF, aaand sometimes ddJPEG, files, 2) Photo scanning apps ddthat output JPEG files, and have editing functions useful for photo rather than document editing; 3) Barcode adlikesas QR ascode asscanning apps that then search the internet for information associated with the code.
Now that you passed high school, applied to your abroad-university, packed your luggage and set your foot into your university student accommodation, you are about to meet various types of roommates that every international student has to get ready for meeting.
Get original essayThe Messy
We all mess up our rooms and belongings every now and then, especially when we're about to deliver an important assignment or about to get into a difficult exam. But when it comes to other people, they are more than that. Some people will treat the floor as if it is their wardrobe and their beds as their studying desks, and doing the dishes is absolutely unthinkable.
The Neatly Freaky
These roommates are the exact opposite of the previous ones; they vaccuum the crumbs on the carbet even if it's dawn and they will make sure that the very last teaspoon is not left unwashed in the kitchen's sink. You have to be grateful and help a little, but also be cautious when trying to draw their attention to what bothers you.
Partying Chap
Whether it is in the middle of exams or the beginning of the semester, these mates will always find a good reason to party, not alone! They will invite friends over and party hard till 5 AM maybe, so be ready to join the party or do some confrontations.
Nocturnal Mate
University life is different from the work-life that comes later. In university, you can be a nighter as long as you study well and deliver your assignments on time. However, this could be a troublesome if you are a morning person and your mate is a night owl. Some people just cannot function properly except at the late hours of the night. We could also argue that you could be the night own and your flatmate is the sunshine. Either way, you will have to adjust to having someone with you with a different schedule and different lifestyle. What's a college education without learning to accept diversity, right?
Friendly
Even this type has subtypes under it. Who is friendly to someone could be not to others and vice versa. We should then believe that everyone is friendly but not necessarily to us. So you have to get to know your flatmate better in order to know if his character matches with yours or not, because after all university life is incomplete if you are not making new foreign friends all the way.
Creativity and innovation are pretty similar but also they most of time may rely on each other to know how ? we need to know what does each one mean then when we combine them we will see what could happen and give examples for them, and what could happen if we use them digitally? When you think of creative person you imagine someone colorful and fun but it could be creative in different ways isn’t necessarily to be like that it maybe could person who are unsocial or under fifteen years old and in different majors. Each creative person searching for aspirations from everything and can be very smart and genus in his or her major.
Get original essayWhat are the difference between advertisers people and artists on painting? A huge difference but each one of them can be creative equally, for example, the artist paints his or her painting perfectly in different and new way that expresses many emotions that no one did it before, but he or she need people to see or to buy it. Now it’s the advertiser role to help the artist, so the advertiser need think out of the box to attract people and to target people who will buy and be interested. Creativity is unusual way to express things. It is not necessary to be new things but it have to be introduced in new way. Now ending of 2018 we reached a high technology in many ways that can help people in different sectors business or health.“ To live a creative life, we must lose our fear of being wrong”
Joseph Chilton Pearce
Innovation in the other hand is representing a new idea and improving it to be effective and more acceptable and the person with innovative idea could be entrepreneur, but only if he or she was the only person on his or her field and good at it, back to innovation, so it is a new idea in a new way that should improved to be efficient and more productive and people could accept it.
Many companies search for innovative people it is like finding talent people but in idea or searching for idea and buy it from them like what happened with to Android Mobile operating system they went to Samsung to offer them the new system but they refused to buy it, but then Google knew about Android system so they took the opportunity and bought it and released the first version 1. 0 in September 23 2007. This kind of innovative idea and Google knew it and took the opportunity, now Samsung paying money so they can use it and come a harsh competitor to Apple Company. “Innovation distinguishes between a leader and a follower “
Steve Jobs
Combined We talked about innovation and creativity and the difference between them. Now we will see what happen if we combine them. They can produce Significant things. People with both advantages will be famous and billionaires like what happened to the founder of eBay Pierre Omidyar who became one of the American billionaire and he is an entrepreneur, so entrepreneurship result from Creative plus innovation. Pierre Omidyar created an digital innovation. He create an auction site as a hoppy he didn’t think he will earn ten thousand dollars per month from his hoppy, so he became more innovative and creative to improve his site and become one of the E-commerce giants. So digital creative innovation is not new. People start to knew about it when the business starts to began from 1995 one of the business is the online bookstore "Amazon ".
Before, was only internet available for government and scientists. Digitally Digital creative innovation is like the rare combination for huge success but doesn’t mean unlimited success some companies like Paypal couldn’t continue alone because of the high percentage of thier transactions profit went to ebay. They were connected to eBay even they are different company so to prevent their company to fall down they decided to aligned with eBay. Both are a high digital creative innovation ideas came together, what’re couple!. Now we have more opportunities to find an innovative creative ideas because of the increasing of people needs and companies. Like eBay could not earn more money without PayPal the safety of transfering money between the seller and the buyer and there were no need to send mony by postmail and waiting a long time to send and receive the product and money. Ending of 2018 TSMC (Taiwan Semiconductor Manufacturing Company) reached 7nm( nanometer)that our IPhones Processor have it. It is the highest technology that the humanity reached. These all innovation it may will improve our lives in many technological ways. In general the Nanotechnology could helps the humanity life.
Our society has inclined to Digital. What does this mean for our culture and our lives? How can long-forgotten stories and places be rediscovered with digital technology? How is social media changing our identities? The digital society presents us with new challenges and the answer can be found in humanities. In a rapidly growing and changing world, humanities are facing tremendous pressure to adapt itself to change and it is science and technology that gave it a helping hand. Humanities and Digital Technology are no longer two separate disciplines, they are complementary to each other. The study aims to see the possibilities of cultivating the English language and literature through Digital Humanities and also provide a critical perspective of the impact of digitization on human lives.
Get original essayKeywords : Digital humanities, Technology, English language, English Literature.
In the manuscript culture, one interesting thing about it is that knowledge can travel without the knower. The knower can write down whatever they have to and the knowledge can travel without the body of the knower requiring to travel. That was a certain kind of revolutionary change in the history of literature. In manuscripts, there will be few copies of a particular text. When there are copies there are interpolations and many things which would make each manuscript copy significantly different from another one and people would have to sit down and copy these manuscripts. The scholars studying would be monks, studying in their monasteries and they would be studying on their own. The monks in monasteries they can discuss with each other but they cannot discuss things with the larger scholarly community. All that change is very significant with the coming of printing where the number of books available increased exponentially. This led to an increase of books in the libraries in people’s personal collections, particularly princesses and Universities. The exchange of knowledge becomes a great deal. The invention of the print brought a certain change in the way of exchange of knowledge and in the way of knowledge production takes place and Digital is the next leap. The change in technology leads to the shifting of this possibility.
Recent advances in digital technologies have provided unprecedented opportunities for digital scholarship in the humanities. In the early 2000s with developments in communication technologies, the digital revolution emerged. A new discipline Digital humanities were digital technologies intersect with the humanities. In the context of the covid pandemic that has probably changed the traditional approaches in education. Today students of literature have to break from the tyranny of the printed text and move confidently into the fluid dynamics of interdisciplinarity.
Digital Humanities is a field of professorial activity at the convergence of computing or digital technologies and the disciplines of the humanities. It is the systematic use of digital resources as well as the analysis application of the humanities Digital humanities is a crossover discipline connecting the social sciences like History and Philosophy, Archeology and Anthropology, Statistics, Linguistics, literature and the art library, and information science, media studies, design, etc.
To have a clear idea of the digital humanities is to reject the idea that digital technology is invading the academy. Computers were not only, as one might expect, as mere storage for large libraries of text. The internet has enabled the use of digital files from almost anywhere on the globe. This access to information has an immense effect on the ability to undertake research in the arts and humanities.
Digital humanities subside from the field of humanities computing. In the pioneering work of Jesuit scholar Roberto Busa, which began in 1946, and of English professor Josephine Miles. In association with IBM, Busa and his team created a computer-generated concordance to Thomas Aquinas's writings known as the Index Thomisticus. Other scholars began using the mainframe of computer’s artificial intelligence tasks like word-searching, sorting, and counting, which was more agile than processing information from texts with handwritten or typed index cards.
In the decades archaeologists, classicists, historians, literary scholars, and a broad spectrum of humanities researchers in other disciplines applied to emerge computational artificial intelligence methods to transform humanities scholarship. The first exclusive journal in the digital humanities was Computers and the Humanities, which was launched in 1966.
Digital humanities are at the cutting edge of applying computer-based technology in the humanities. Earlier it was called as humanities computing, the field has developed over the past forty years. At first concentrated on inventing digital tools and modeling of archives and databases for texts, artworks, and different materials. As artificial intelligence evolved computers provided increasingly sophisticated ways of operating and searching. With recent developments in digital imaging, it is now feasible to produce high-quality reproductions of books and artworks that can change our potential to study them. Digital humanities scholars use different types of digital tools for research, which may be as small as a mobile device or as large as a virtual reality lab. Some scholars prefer advanced programming languages, while others use less complex tools, depending on their needs.
DIRT (Digital Research Tools Directory) and TAPOR (Text Analysis Portal for Research) offer a register of digital analysis tools for students. A free example of an online textual analysis program is Voyant Tools, which solely needs the user to copy and paste either a body of text or a Universal resource locator URL and then click the 'reveal' button to run the program. There is a list of online or downloadable Digital Humanities tools that are aimed toward helping students and others who lack access to funding or institutional servers. Open source web publishing platforms like WordPress and Omeka also are widespread tools. There was a necessity for a consistent protocol for tagging digital texts, and therefore the Text Encryption Initiative (TEI) was developed. The TEI project was launched in 1987 and printed the first full version of the TEI Guidelines in May 1994.
As museums, libraries, archives, and alternative establishments have digitized collections and artifacts, new tools and standards have been developed that flip those materials into machine-readable data. Optical Character Recognition (OCR) and the Text Encoding Initiative (TEI), for example, have enabled humanities researchers to huge amounts of textual data. However, these advances are not limited just to text. Sound, images, and video have all been subject to these new styles of analysis. The multimedia system nature of the web has allowed Digital Humanities work to incorporate audio, video, and alternative parts in addition to text. Digital tools also can be freely accessed over the web so they can be easily incorporated into other projects, enabling the rapid diffusion of new methods, tools, and ideas across disciplinary boundaries. These digital technologies open up exciting opportunities for connecting the humanities to a wider public culture.
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Get custom essayIn the constantly growing and changing field of digital humanities technology and science are no longer two separate disciplines they are two sides of the same approach. Digital humanity is a program for humanists of the future.
In today’s day and age, Digital Marketing has become an intrinsic part of everybody’s life. Right from personal use to professional use, Digital marketing is a playground for people to keep their lives updated as well as to network with potential clients which will help their business grow.
Get original essayIndia is the second largest country with over 462 million internet users. With a massive internet, population comes the opportunity for business owners to network with potential customers. This is one huge reason why Digital Marketing has emerged as one of the most sought-after profession not only in India but globally as well.
Customers are often researching online and then buying in stores and also browsing in stores and then searching for other options online. Online customer research into products is particularly popular for higher-priced items as well as consumable goods like groceries and makeup. Consumers are increasingly using the Internet to look up product information, compare prices, and search for deals and promotions.
Objectives
Objective 1: To know the changes made in the modern marketing system.
Objective 2: To understand the new technology how it has been making the speed marketing of the product?
Objective 3: To facilitate the comparison between offline marketing and online marketing.
Objective 4: To know the current situation of the market.
In order to accomplish the above objectives, an attempt has been made to study the importance of digital marketing in business. For the research work, the statistical data was collected from the secondary sources like published and unpublished data collected from different organizations, agencies, and websites. Reputed journals were also used for collecting relevant information.
Digital marketing's development since the 1990s and 2000s has changed the way brands and businesses use technology for marketing. As digital platforms are increasingly incorporated into marketing plans and everyday life, and as people use digital devices instead of visiting physical shops, digital marketing campaigns are becoming more prevalent and efficient.
Digital marketing methods such as search engine optimization (SEO), search engine marketing (SEM), content marketing, influencer marketing, content automation, campaign marketing, data-driven marketing, e-commerce marketing, social media marketing, social media optimization, e-mail direct marketing, display advertising, e-books, and optical disks and games are becoming more common in our advancing technology. In fact, digital marketing now extends to non-Internet channels that provide digital media, such as mobile phones (SMS and MMS), callback, and on-hold mobile ringtones
Digital marketing is the marketing of products or services using digital technologies, mainly on the Internet, but also including mobile phones, display advertising, and any other digital medium.
Digital marketing, the promotion of products or brands via one or more forms of electronic media, differs from traditional marketing in that it uses channels and methods that enable an organization to analyze marketing campaigns and understand what is working and what isn’t – typically in real time.
Digital marketers monitor things like what is being viewed, how often and for how long, sales conversions, what content works and doesn’t work, etc. While the Internet is, perhaps, the channel most closely associated with digital marketing, others include wireless text messaging, mobile instant messaging, mobile apps, podcasts, electronic billboards, digital television and radio channels, etc.
Digital media is so pervasive that consumers have access to information any time and any place they want it. Gone are the days when the messages people got about your products or services came from you and consisted of only what you wanted them to know. Digital media is an ever-growing source of entertainment, news, shopping and social interaction, and consumers are now exposed not just to what your company says about your brand, but what the media, friends, relatives, peers, etc., are saying as well. And they are more likely to believe them than you. People want brands they can trust, companies that know them, communications that are personalized and relevant, and offers tailored to their needs and preferences.
Three keys to digital marketing success:
What does it take to do digital marketing right? Here are three keys to digital marketing success:
Manage complex customer relationships across a variety of channels – both digital and traditional. Respond to and initiate dynamic customer interactions. Extract value from big data to make better decisions faster.
History:
The term digital marketing was first coined in the 1990s, In 2000, a survey in the United Kingdom found that most retailers had not registered their own domain address.
Digital marketing became more sophisticated in the 2000s and the 2010s when the proliferation of devices' capable of accessing digital media led to sudden growth.[ Statistics produced in 2012 and 2013 showed that digital marketing was still growing.
Digital marketing is also referred to as 'online marketing', 'internet marketing' or 'web marketing'. The term digital marketing has grown in popularity over time. In the USA online marketing is still a popular term. In Italy, digital marketing is referred to as web marketing. Worldwide digital marketing has become the most common term, especially after the year 2013.
Digital media growth was estimated at 4.5 trillion online ads served annually with digital media spend at 48% growth in 2010. An increasing portion of advertising stems from businesses employing Online Behavioural Advertising (OBA) to tailor advertising for internet users, but OBA raises the concern about consumer privacy and data protection.
One of the major changes that occurred in traditional marketing was the "emergence of digital marketing" (Patrutiu Baltes, Loredana, 2015), this led to the reinvention of marketing strategies in order to adapt to this major change in traditional marketing (Patrutiu Baltes, Loredana, 2015).
As digital marketing is dependent on technology which is ever-evolving and fast-changing, the same features should be expected from digital marketing developments and strategies. This portion is an attempt to qualify or segregate the notable highlights existing and being used as of press time.
1. Segmentation: more focus has been placed on segmentation within digital marketing, in order to target specific markets in both business-to-business and business-to-consumer sectors.
2. Influencer marketing: Important nodes are identified within related communities, known as influencers. This is becoming an important concept in digital targeting. It is possible to reach influencers via paid advertising, such as Facebook Advertising or Google Adwords campaigns, or through sophisticated scam (social customer relationship management) software, such as SAP C4C, Microsoft Dynamics, Sage CRM and Salesforce CRM. Many universities now focus, at Masters level, on engagement strategies for influencers.
To summarize, Pull digital marketing is characterized by consumers actively seeking marketing content while Push digital marketing occurs when marketers send messages without that content being actively sought by the recipients.
A strategy that is linked to the effectiveness of digital marketing is content marketing. Content marketing can be briefly described as "delivering the content that your audience is seeking in the places that they are searching for it".It is found that content marketing is highly present in digital marketing and becomes highly successful when content marketing is involved. This is due to content marketing making your brand more relevant to the target consumers, as well as more visible to the target consumer.
Marketers also find email an effective strategy when it comes to digital marketing as it is another way to build a long-term relationship with the consumer. Listed below are some aspects that need to be considered to have an effective digital media campaign and aspects that help create an effective email system.
Interesting mail titles differentiate one advertisement from the other. This separates advertisements from the clutter. Differentiation is one factor that can make an advertisement successful in digital marketing because consumers are drawn to it and are more likely to view the advertisement.
Establishment of customer exclusivity: A list of customers and customer's details should be kept on a database for follow up and selected customers can be sent selected offers and promotions of deals related to the customer's previous buyer behavior. This is effective in digital marketing as it allows organizations to build up loyalty over email
Low Technical Requirements: In order to get the full use out of digital marketing it is useful to make your advertising campaigns have low technical requirements. This prevents some consumers not being able to understand or view the advertising campaign.
Rewards: The lucrative offers would always help in making your digital campaign a success. Give some reward at the end of the campaign. This would definitely invite more engagement and word of mouth publicity
Digital marketing activity is still growing across the world according to the headline global marketing index. Digital media continues to rapidly grow; while the marketing budgets are expanding, traditional media is declining (World Economics, 2015). Digital media helps brands reach consumers to engage with their product or service in a personalized way. Five areas, which are outlined as current industry practices that are often ineffective are prioritizing clicks, balancing search and display, understanding mobiles, targeting, viewability, brand safety and invalid traffic, and cross-platform measurement (Whiteside, 2016).[37] Why these practices are ineffective and some ways around making these aspects effective are discussed surrounding the following points.
Digital marketing is facilitated by multiple channels, As an advertiser one's core objective is to find channels which result in maximum two-way communication and a better overall ROI for the brand. There are multiple online marketing channels available namely;
Affiliate marketing - Affiliate marketing is perceived to not be considered a safe, reliable and easy means of marketing through an online platform. This is due to a lack of reliability in terms of affiliates that can produce the demanded number of new customers. As a result of this risk and bad affiliates, it leaves the brand prone to exploitation in terms of claiming commission that isn’t honestly acquired. Legal means may offer some protection against this, yet there are limitations in recovering any losses or investment.
Display advertising - As the term infers, Online Display Advertisement deals with showcasing promotional messages or ideas to the consumer on the internet. This includes a wide range of advertisements like advertising blogs, networks, interstitial ads, contextual data, ads on the search engines, classified or dynamic advertisement etc
Email marketing - Email marketing in comparison to other forms of digital marketing is considered cheap; it is also a way to rapidly communicate a message such as their value proposition to existing or potential customers.
Social Media Marketing - The term 'Digital Marketing' has a number of marketing facets as it supports different channels used in and among these, comes the Social Media. When we use social media channels ( Facebook, Twitter, Pinterest, Instagram, Google+, etc.) To market a product or service, the strategy is called Social Media Marketing.
Digital marketing system
Digital marketing planning is a term used in marketing management. It describes the first stage of forming a digital marketing strategy for the wider digital marketing system. The difference between digital and traditional marketing planning is that it uses digitally based communication tools and technology such as Social, Web, Mobile, Scannable Surface. Nevertheless, both are aligned with the vision, the mission of the company and the overarching business strategy.
Stages of planning
Using Dr. Dave Chaffey’s approach, the Digital Marketing Planning (DMP) has three main stages; Opportunity, Strategy, and Action. He suggests that any business looking to implement a successful digital marketing strategy must structure their plan by looking at opportunity, strategy, and action. This generic strategic approach often has phases of situation review, goal setting, strategy formulation, resource allocation and monitoring.
1) Opportunity
To create an effective DMP a business first needs to review the marketplace and set ‘SMART’ (Specific, Measurable, Actionable, Relevant and Time-Bound) objectives. They can set SMART objectives by reviewing the current benchmarks and Key Performance Indicators (KPIs) of the company and competitors. It is pertinent that the analytics used for the KPIs be customized to the type, objectives, mission, and vision of the company.
Companies can scan for marketing and sales opportunities by reviewing their own outreach as well as influencer outreach. This means they have a competitive advantage because they are able to analyze their co-marketers influence and brand associations.[60]
To cease opportunity, the firm should summarize their current customers’ personas and purchase journey from this they are able to deduce their digital marketing capability. This means they need to form a clear picture of where they are currently and how many resources they can allocate for their digital marketing strategy i.e. Labour, time etc. By summarizing the purchase journey, they can also recognize gaps and growth for future marketing opportunities that will either meet objectives or propose new objectives and increase profit.
2) Strategy
To create a planned digital strategy, the company must review their digital proposition (what you are offering to consumers) and communicate it using digital customer targeting techniques. So, they must define the online value proposition (OVP), this means the company must express clearly what they are offering customers online e.g. Brand positioning.
The company should also (re)select target market segments and personas and define digital targeting approaches.
After doing this effectively, it is important to review the marketing mix for online options. The marketing mix comprises the 4Ps - Product, Price, Promotion, and Place. Some academics have added three additional elements to the traditional 4Ps of marketing Process, Place and Physical appearance making it 7Ps of marketing.[63]
3) Action
The third and final stage requires the firm to set a budget and management systems; these must be measurable touchpoints, such as audience reached across all digital platforms. Furthermore, marketers must ensure the budget and management systems are integrating the paid, owned and earned media of the company. The Action and final stage of planning also require the company to set in place measurable content creation e.g. Oral, visual or written online media.
After confirming the digital marketing plan, a scheduled format of digital communications (e.g. Gantt Chart) should be encoded throughout the internal operations of the company. This ensures that all platforms used to fall in line and complement each other for the succeeding stages of digital marketing strategy.
Innovations:
That being said, there is always space for improvement, and just like getting writing help online, we are bound to witness the next step in digital marketing next year. What are some of the most influential and groundbreaking changes we can anticipate in 2018 when it comes to digital marketing?
a) Social media customer engagement
The most popular social media platforms have been known to implement new experimental features into their systems faster than anyone else. Such was the implementation of live feeds and hashtags in Facebook once it acquired Instagram and started its path towards transformation.
Customer engagement has always been an issue when it comes to social media, with managers who don’t know how to go about communicating with their customers effectively. Looking for college term papers for you has always been a matter of luck on social media and that is about to change. In 2018, we can look forward to a more refined system of public communication between businesses and customers, with updated business pages and specialized groups available to anyone interested in communication.
b) Support automation through Big Data
Being available for clients and customers 24/7 can be difficult, especially for small firms and startups. That is why big data is going to change the way we engage customers through support in a big way. Automation is nothing new to the marketing scene, with chatbots being present on major sites throughout the internet, custom paper writing sites included.
What makes big data implementation so different from regular chatbots is the fact that these algorithms will learn from the company’s data servers in order to learn and evolve over time. This process is more commonly known as machine learning, and it will allow companies to fully automate their customer support sectors with only supervisors being needed for the management of said services.
c) Wearable digital apparel
Digital watches, hearing devices, and pacemakers are something we are accustomed to seeing in today’s age. However, with the advent of 2018, we will see smart devices implemented in our everyday apparel and styling.
These devices already exist in the form of Apple and Android watches which allow for augmented reality features in our day-to-day activities. These include heart rate and pacing monitors, online news feeds, looking for college paper help, email notifications as well as Google search capabilities. This is possible through a synchronization process with the main device we keep in our pockets, mostly in the form of a mobile phone that pairs up with the apparel item.
d) Mobile marketing development
Mobile devices are coming to the forefront when it comes to marketing, application development, and overall customer experience attention. This will allow companies to develop specialized marketing strategies aimed specifically at the mobile market, which is considerably larger than the desktop user market.
The reason for this is that everyone has some form of a smartphone in their pocket nowadays, with a writing service or similar professional service within reach. Serving curated marketing content designed specifically for mobile applications is becoming easier than ever before thanks to this fact and the market are only bound to grow in the coming year.
e) Interactive marketing content
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Get custom essayLastly, it will no longer be enough to serve up content to the potential customers and hope for the best. With the recent rise of VR and AR technologies not only in games and applications but also in term paper help and similar online services, people are expecting more care and attention in their content. Live to stream, Ask Me Anything (AMA) sessions, as well as any kind of live textual and visual interaction with your customer base, does provide the needed interactive experience.
A 700-MHz to 1.6-GHz RF power digital-to-analog converter with programmable integrated harmonic cancellation and mixed-signal filtering is depicted. Harmonic cancellation is achieved by splitting the power amplifier into different parts, driving different segments of the PA with phase-shifted versions of the local oscillator(LO) signals, and adding at the output. Mixed-signal filtering is realized in a similar way but with sections driven with delayed versions of the input data. The data delays and phase shift are implemented to operate across a wide frequency range and are reconfigurable too. For boosting efficiency, 25% duty-cycle LO signals are used. A technique to correct for IQ constellation distortion made by these 25% duty cycle LO signals is introduced and confirmed in measurements. The transmitter(TX) operates at an extreme sampling rate of 500 Mega Samples per second and an output power of 25.6 dBm is achieved for an output load of 100 ohm when harmonic cancellation is empowered. The TX demonstrates 24dB to 42 dB of third harmonic cancellation for continuous wave signals across a 700-MHz to 2-GHz frequency range, achieving an HD3 as low as -57 dB. The TX achieves an HD3 drop of 33 dB and an 18-dB notch at 40-MHz offset with 20-MHz long-term evolution (LTE) data.
Get original essayDigital power amplifiers(PAs) have become progressively striking because of their technology quantifiability and the capability to use them as the core of a Radio Frequency digital-to-analog converter(DAC). RF DACs are demanding as they enable for digital input data to be changed directly to RF output signals [1] – [3]. The direct conversion from digital to radio frequency signals permits the easiness in reconfiguring the transmitter(TX) to meet different standards. Current works on multi-standard digital PAs [2] has established digital PAs as a feasible option for flexible transmitters. However, the 2 major issues which must be kept in consideration before this becomes a hands-on and efficient solution are harmonic emissions and quantization noise.
Basically, digital PAs, which works as switching PAs, produce strong harmonic content. Digital PAs generate square wave (voltage or current) which then is filtered with an output network. The power of each harmonic, with n as the harmonic number, attenuates with 1/n2 for a square wave, meaning that without extra filtering, the third harmonic is only 9.5 dB lesser than the fundamental in power. Naturally, using a narrowband and high-order fixed filter these harmonics are suppressed. A reconfigurable transmitter(TX) would demand a large amount of these filters, which would be expensive and would add an additional loss from the switch network. Due to which, an integrated and reconfigurable resolution is necessary, in aggregation with a wideband output network.
Moreover, an RF DAC creates quantization noise, as is basically the case with all DACs. Which in turn can cause problems with coexistence in frequency division duplex systems, as a nearby receiver (RX) can be desensitized by this quantization noise. In the long-term evolution(LTE) standard, for eg., a receiver could be offset only by 40MHz. Adding resolution or oversampling to the DACs, is a commonly used practice to reduce quantization noise, but is generally pricey either in area or in power. If the RX frequencies are identified, filtering selectively at those frequencies could be a less expensive decision. Power amplifier are used to deliver a relatively high amount of power, usually to a low resistance load. Ideal PA will deliver 100% of the power it draws from the supply to load. Practically, this can never occur. Thus, amplifiers are differentiated into variety of classes and these classes generally differ in their angle of conduction, efficiency, linearity, and in the amount of distortion they introduce to the system. To remove this harmonic distortion,s they have developed cancellation techniques.
The reason why cancellation techniques are implemented is because of Harmonic distortion, which principally comes from non-linear loads. The application of power electronic is causing increased level of harmonics. It can cause serious problems for the use of electric power and can reduce the life of electronic devices used.
A. Harmonic Cancellation
The two approaches which are generally used to mitigate the effects of heating due harmonics, and a combination of the two approaches is often implemented. One strategy is to reduce the magnitude of the harmonic waves usually by filtering, the other being, using the system components that can handle the harmonics better. This implementation uses two PAs with equal weights using LO signals with a phase-shift of 60 degree, which are then summed at their outputs. This approach successfully removes the second and third order harmonics. To make the output more harmonic-free filters are used which are described in next section.
B. Mixed-Signal Filtering
The filter which is generally used to remove harmonic signals can be constructed by adding an inductance in series power factor correction capacitor. This circuit can be tuned for a frequency close to that of the trivial harmonic signal which is often of the 5th order. By this way we can attenuate the unwanted harmonic. The approach implemented here is, a delay line is used to generate delayed versions of the input data. These delayed versions are used to drive different power amplifiers which are summed at the output, employing a programmable FIR.
C. Limitation of techniques
In previously described techniques the circuits rely on summing sub-power amplifiers with different input signals. The linearity of this summation is a critical requirement which becomes difficult at high signal levels due to increased device non-linearity.
Delay Generation. The data delay line is implemented using a chain of flipflops operating at the data rate, with a highest delay of 25 clock periods. This enables for a notch to be placed at an offset of as close as fs/50 from the center frequency,for which fs being the sample rate. This operation was chosen due to its relative easiness. Unlike an inverter-based delay line, the delay of each element depends only on the data rate as long as the flip-flops can operate at that same data rate. This delay generation remains frequency flexible as long as delay line operates at the desired fs . The outputs of this delay line are fed to a set of MUXs associated with each sub-PA. The select bits of each MUX are set through a scan chain, and each MUX can be set independently of one another, allowing for full programmability of the mixed-signal FIR filter.
Although harmonics will always be a part of the system. this implementation can reduce different orders of harmonic signals for efficient mode of communication system.
[1] D. Chowdhury, S. V. Thyagarajan, L. Ye, E. Alon, and A. M. Niknejad, “A fully-integrated efficient CMOS inverse class-D power amplifier for digital polar transmitters,” IEEE J. Solid-State Circuits, vol. 47, no. 5, pp. 1113–1122, May 2012.
[2] H. Wang et al., “A highly-efficient multi-band multi-mode all-digital quadrature transmitter,” IEEE Trans. Circuits Syst. I, Reg. Papers, vol. 61, no. 5, pp. 1321–1330, May 2014.
[3] B. Yang, E. Y. Chang, A. Niknejad, B. Nikoli´c, and E. Alon, “A 65 nm CMOS, I/Q RF power DAC with 24–42 dB 3rd harmonic cancellation and up to 18 dB mixed-signal filtering,” in Proc. Symp. VLSI Circuits, Kyoto, Japan, Jun. 2017, pp. C302–C303.