Digital signal processing
Lexical units:
digital signal processing (DSP) – цифровая обработка сигналов
real-world analog signal – практический аналоговый сигнал
analog-to-digital converter – аналого-цифровой преобразователь
output signal – выходной сигнал
computational power – вычислительные возможности
purpose-built – специализированный
application-specific integrated circuit (ASIC) –
интегральная схема, специализированная для решения конкретной задачи
field-programmable gate array (FPGA) –
программируемая пользователем вентильная матрица
stream processor – процессор для потоковой обработки данных
spatial domain – пространственная область
multidimensional – многомерный
autocorrelation – автокорреляционная функция
wavelet – вейвлет, всплеск
(математическая функция анализа частотных компонентов данных)
discrete Fourier transform – дискретное преобразование Фурье
recognition – распознавание
crossover – разделитель спектра сигнала
equalization – стабилизация или компенсация канала связи
magnetic resonance imaging (MRI) – отображение магнитного резонанса
fixed-point arithmetic – арифметическая операция с фиксированной запятой
(формат представления вещественного числа в памяти ЭВМ в виде целого числа)
floating point arithmetic – арифметическая операция с плавающей запятой
(форма представления действительных чисел, в которой число хранится в форме мантиссы и показателя степени)
TEXT
Digital signal processing (DSP) is concerned with the representation of signals by a sequence of numbers or symbols and the processing of these signals. It is clear that DSP and analog signal processing are subfields of such a great modern scientific doctrine as signal processing.
The goal of DSP is usually to measure, filter and then, if necessary, compress continuous real-world analog signals. The first step is usually to convert the signal from an analog to a digital form, by sampling it using an analog-to-digital converter, which turns the analog signal into a stream of numbers. However, often, the required output signal is another analog output signal, which requires a digital-to-analog converter. Even if this process is more complex than analog processing and has a discrete value range, the application of computational power to digital signal processing allows for many advantages over analog processing in many applications, such as error detection and correction in transmission as well as data compression.
DSP algorithms have long been run on standard computers, on specialized processors called digital signal processors, or on purpose-built hardware such as application-specific integrated circuit (ASIC). Today there are additional technologies used for digital signal processing including more powerful general purpose microprocessors, field-programmable gate arrays, digital signal controllers, and stream processors.
In DSP, engineers usually study digital signals in one of the following domains: time domain (one-dimensional signals), spatial domain (multidimensional signals), frequency domain, autocorrelation domain, and wavelet domains. They choose the domain in which to process a signal by trying different possibilities as to which domain best represents the essential characteristics of the signal. A sequence of samples from a measuring device produces a time or spatial domain representation, whereas a discrete Fourier transform produces the frequency domain information, that is the frequency spectrum. Autocorrelation is defined as the cross-correlation of the signal with itself over varying intervals of time or space.
The main applications of DSP are audio signal processing, audio compression, digital image processing, video compression, speech processing, speech recognition, digital communications, RADAR, SONAR, seismology, and biomedicine. Specific examples are speech compression and transmission in digital mobile phones, room correction of sound in hi-fi and sound reinforcement applications, weather forecasting, economic forecasting, seismic data processing, analysis and control of industrial processes, medical imaging such as CAT scans and MRI (magnetic resonance imaging), MP3 compression, computer graphics, image manipulation, hi-fi loudspeaker crossovers and equalization, and audio effects for use with electric guitar amplifiers.
Digital signal processing is often implemented using specialised microprocessors to process data using fixed-point arithmetic, although some versions are available which use floating point arithmetic and are more powerful. For faster applications FPGAs might be used. Beginning in 2007, multicore implementations of DSPs have started to emerge from a range of global companies. For faster applications with vast usage, ASICs might be designed specifically. Vice versa, a traditional slower processor such as a microcontroller may be adequate. Also a growing number of DSP applications are now being implemented on Embedded Systems using powerful PCs with a Multi-core processor.
Comprehension
Exercise 1.True or false?
1) A sequence of samples from a measuring device produces a time or spatial domain representation.
2) The main applications of DSP are audio signal processing and audio compression only.
3) It is obvious that DSP and analog signal processing are subfields of signal processing.
4) At first, engineers must convert the signal from an analog to a digital form.
5) DSP has never been used in analysis and control of industrial processes.
6) A microcontroller may be adequate enough for faster DSP applications.
7) Multidimensional signals are usually referred to the spatial domain.
8) DSP algorithms are not run on standard computers any more.
9) ASIC is the abbreviation for a field-programmable gate array.
10) If the required output signal is another analog output signal you have to use a digital-to-analog converter.
Exercise 2.Complete the sentences using the correct words from the text:
1) Today there are additional … used for digital signal … including more … general purpose microprocessors.
2) The … of DSP is usually to measure, filter and then … continuous …-… analog signals.
3) DSP is concerned with the … of signals by a … of numbers or symbols and the … of these signals.
4) A growing number of DSP … are now being implemented on … Systems using … PCs.
5) … is defined as the …-… of the signal with itself over varying … of time or space.
6) Specific examples of DSP are speech … and … in … mobile phones.
7) Some versions are … which use … point … and are more powerful.
8) Multicore … of DSPs have started to … from a range of … companies.
Vocabulary
Exercise 3.Give the Russian or English equivalents for the following word combinations:
Hi-fi loudspeaker crossovers and equalization; использование специализированных процессоров для обработки данных; application of computational power to digital signal processing; цифро-аналоговый преобразователь; time and spatial domain representation; распознавание многоядерного процессора; faster applications with vast usage; временнáя область с одномерными сигналами; field-programmable gate arrays, digital signal controllers and stream processors; настройка звука в закрытом помещении.
Exercise 4.Match the words with their meanings:
| 1) signal | a) working with numbers |
| 2) recognition | b) an electronic circuit that can execute computer programs |
| 3) processor | c) systematic arrangement of objects, usually in rows and columns |
| 4) multicore | d) connected line of events |
| 5) sequence | e) a type of microprocessor design in which multiple processors coexist on the same chip |
| 6) array | f) identification of smth. already known or acknowledgement of smth. as valid |
| 7) arithmetic | g) process of adjusting the strength of certain frequencies within a signal |
| 8) equalization | h) a discrete part of a communication |
Exercise 5.Translate from Russian into English:
1) Цифровая обработка сигналов – это процесс преобразования сигналов, представленных в цифровой форме. 2) Примером интегральной схемы, специализированной для решения конкретной задачи, может являться микросхема, разработанная только для управления мобильным телефоном. 3) Если бы алгоритмы цифровой обработки сигналов не были проверены на специальных процессорах, они бы не применялись в обычных персональных компьютерах. 4) Программируемая пользователем вентильная матрица (ППВМ) является полупроводниковым устройством, которое может быть сконфигурировано производителем или разработчиком после изготовления. 5) Особенностью ППВМ является то, что конфигурация соединений между её блоками может меняться с помощью специальных сигналов, посылаемых схеме. 6) Принципом магнитно-резонансной томографии (magnetic resonance tomography) является отображение магнитного резонанса, то есть метод измерения электромагнитной реакции ядер атомов водорода на их возбуждение электромагнитными волнами. 7) Раньше обработка аудио-сигналов была обязательна для радиовещания, поскольку в студиях возникали проблемы, связанные с установлением соединения при передаче. 8) Временнáя область описывает анализ математических функций или физических сигналов по отношению ко времени. 9) Арифметическая операция с фиксированной запятой широко применяется в цифровой обработке сигналов. 10) Электронное устройство, преобразующее напряжение в двоичный цифровой код, называется аналого-цифровым преобразователем.
Exercise 6.Make up the summary of the text and write its annotation.
Discussion
Exercise 7.Work in pairs or in small groups. Share in the discussion. Use the following questions as prompts:
1) Could you interpret the term “DSP” and give its definition?
2) What is the general purpose of DSP?
3) Would you describe the initial stage of digital signal processing?
4) What is an ASIC?
5) What additional technologies are used for digital signal processing nowadays?
6) What domains of studying digital signals in DSP do you know?
7) How can you correlate a discrete Fourier transform with DSP?
8) Could you name the most important – from your point of view – applications of DSP?
9) What items may be used for faster DSP applications? And for slower ones?
LESSON 4
WHAT IS A SENSOR?
Lexical units:
touch-sensitive – сенсорный
to dim – гаснуть
output – выходной сигнал
microscopic scale – микроскопический уровень
MEMS technology – технология микроэлектромеханических систем
to merge into – переходить, превращаться во что-либо
to implement – выполнять, осуществлять
target device – конечный прибор
to obey the rule – соответствовать правилу
linear – линейный (применительно к функции)
deviation – отклонение, девиация
sensitivity error – ошибка чувствительности
dynamic error – динамическая ошибка
bode plot – представление амплитудно-фазовой частоты в логарифме
phase shift – сдвиг по фазе
to some extent – до некоторой степени
random error – случайная (несистематическая) ошибка
resolution – разрешающая способность
to fluctuate – колебаться
scanning tunneling probe – сканирующий туннельный микроскоп
fine – тонкий
tip – наконечник
TEXT
Sensors are used in everyday objects such as touch-sensitive elevator buttons and lamps which dim or brighten by touching the base. There are also innumerable applications for sensors of which most people are never aware. Applications include cars, machines, aerospace, medicine, manufacturing and robotics.
A sensor is a device which receives and responds to a signal. A sensor’s sensitivity indicates how much the sensor’s output changes when the measured quantity changes, i.e. a sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. For instance, if the mercury in a thermometer moves 1 cm when the temperature changes by 1 °C, the sensitivity is 1 cm/°C. Sensors that measure very small changes must have very high sensitivities. Sensors also have an impact on what they measure – a room temperature thermometer inserted into a hot cup of liquid cools the liquid while the liquid heats the thermometer. Sensors need to be designed to have a small effect on what is measured, making the sensor smaller often improves this and may introduce other advantages.
Technological progress allows more and more sensors to be manufactured on a microscopic scale as microsensors using MEMS technology. MEMS (micro-electro-mechanical systems) is the technology of very small mechanical devices driven by electricity. It merges at the nano-scale into nanotechnology. MEMS technology can be implemented using a number of different materials and manufacturing techniques, depending on target device and market sector. The most common materials here are silicon, polymers, and metals.
A good sensor usually obeys the following rules: 1) it is sensitive to the measured property; 2) it is insensitive to any other property likely to be encountered in its application; 3) it does not influence the measured property. Ideal sensors are designed to be linear to some simple mathematical function of the measurement, typically logarithmic. The output signal of such a sensor is linearly proportional to the value or simple function of the measured property. The sensitivity is then defined as the ratio between output signal and measured property.
If the sensor is not ideal, several types of deviations can be observed. For example, the sensitivity may in practice differ from the value specified. This is called a sensitivity error, but the sensor is still linear. If the sensitivity is not constant over the range of the sensor, this is called nonlinearity. Usually this is defined by the amount the output differs from ideal behavior over the full range of the sensor. If the deviation is caused by a rapid change of the measured property over time, there is a dynamic error. Often, this behaviour is described with a bode plot showing sensitivity error and phase shift as function of the frequency of a periodic input signal. If the signal is monitored digitally, limitation of the sampling frequency also can cause a dynamic error. Noise is a random deviation of the signal that varies in time. And, surely, sensors may to some extent be sensitive to properties other than the property being measured. For instance, most sensors are influenced by the temperature of their environment.
These deviations can be classified as systematic errors or random errors. Systematic errors can sometimes be compensated for by means of some kind of calibration strategy. Noise is a random error that can be reduced by signal processing, such as filtering, usually at the expense of the dynamic behaviour of the sensor.
The last item to be considered about the sensor is its resolution. The resolution of a sensor is the smallest change it can detect in the quantity that it is measuring. Often in a digital display, the least significant digit will fluctuate indicating that changes of that magnitude are only just resolved. The resolution is related to the precision with which the measurement is made. Thus, a scanning tunneling probe (a fine tip near a surface collects an electron tunneling current) can resolve atoms and molecules.
Comprehension
Exercise 1.True or false?
1) Most sensors are influenced by the temperature of their environment.
2) When the sensitivity is not constant over the range of the sensor, we call it linearity.
3) Sensors are always sensitive to properties other than the property being measured.
4) An ideal sensor does not influence the measured property.
5) Sensors that measure very small changes must have very high sensitivities.
6) Sensor applications include cookery, forestry, soccer, and veterinary medicine.
7) A scanning tunneling probe collects an electron tunneling current.
8) If the sensor is ideal, several types of deviations can be observed.
9) MEMS technology is used to manufacture sensors on a microscopic scale.
10) The most common materials for MEMS technology are rubber, putty, and timber.
Exercise 2.Complete the sentences using the correct words from the text:
1) The … of a sensor is the … change it can detect in the … that it is measuring.
2) MEMS … merges at the …-… into ….
3) Sensors are used in everyday … such as touch-… elevator ….
4) … is a random … of the signal that … in time.
5) The sensitivity is … as the … between … signal and measured property.
6) A … temperature thermometer … into a hot cup of … cools the liquid.
7) If the … is not … over the range of the sensor, this is called ….
8) Systematic … can … be compensated for by means of some kind of … strategy.
Vocabulary
Exercise 3.Give the Russian or English equivalents for the following word combinations:
Ideal behavior over the full range of the sensor; отклонение, вызвавшее несистематическую ошибку; innumerable applications for sensors in robotics and manufacturing; разработка конечных приборов в соответствии с планом; using a number of different materials and manufacturing techniques; сенсорная панель управления для нового конвейера; limitation of the sampling frequency; колебания значений разрешающей способности; to be linearly proportional to the value; чувствительность тонкого наконечника сканирующего микроскопа.
Exercise 4.Match the words with their meanings:
| 1) manufacturing | a) variation from the common way or from a rule |
| 2) deviation | b) the use of machines, tools and labour to produce goods |
| 3) property | c) way of accomplishing a task that is not immediately obvious |
| 4) surface | d) the study of or a collection of techniques |
| 5) device | e) attribute which is characteristic of a class of objects |
| 6) impact | f) the up-side of a flat object |
| 7) technology | g) any piece of equipment made for a particular purpose |
| 8) technique | h) significant or strong influence; effect |
Exercise 5.Translate from Russian into English:
1) Датчиком является любой элемент измерительного, сигнального, регулирующего или управляющего устройства системы, который преобразует контролируемую величину в удобный для использования сигнал. 2) Сейчас различные датчики широко используют при построении систем автоматизированного управления. 3) Датчики преобразуют температуру, частоту, скорость или напряжение в электрический или оптический сигнал, который можно измерить, передать или преобразовать. 4) Если бы учёные средневековья не изобрели основные измерительные приборы, следующие поколения учёных не совершили бы свои открытия. 5) В сенсорах используется чувствительный элемент, который преобразует параметры среды в пригодный для технического использования сигнал. 6) Иногда датчиком называется часть измерительной или управляющей системы, представляющая собой совокупность измерительных преобразователей. 7) В последнее время часто применяются датчики со сложной обработкой сигналов, возможностями настройки и регулирования параметров и стандартным интерфейсом системы управления. 8) Понятие датчика по практической направленности и деталям технической реализации близко к понятию «измерительный прибор», но показания приборов читаются человеком, а датчики обычно используются в автоматическом режиме. 9) Охранные службы многих стран предлагают инфракрасные сенсоры для защиты от воров и грабителей дорогих музейных экспонатов, а также частных коллекций. 10) Сенсором может называться сам чувствительный элемент любого датчика.
Exercise 6.Make up the summary of the text and write its annotation.
Discussion
Exercise 7.Work in pairs or in small groups. Share in the discussion. Use the following questions as prompts:
1) What is a sensor? Why do people use them in different spheres?
2) What do sensors usually have an impact on?
3) How can you describe the MEMS technology?
4) Could you name the rules a good sensor should obey?
5) When do we have an ideal sensor?
6) Could you give the examples of systematic errors and random ones?
7) What kind of error is noise and why?
8) What is a sensor resolution?
9) What is it related to?
LESSON 5
PRESSURE SENSORS
Lexical units:
transducer – преобразователь, приёмник
imposed – установленный
transmitter – передатчик
sender – датчик, передатчик
to capture – захватить, зафиксировать
combustion pressure – давление сгорания
traffic enforcement – дорожная полиция (в США)
pressure switch – реле давления
perfect vacuum – абсолютный вакуум
PSI (pounds per square inch) – фунт на квадратный дюйм
gauge pressure – манометрическое давление
to calibrate – градуировать, проверять
tire – шина
differential pressure – перепад давления, разность давлений
input – входной сигнал
pressure drop – потеря давления
sealed – запечатанный, опломбированный
drastically – значительно, кардинально
suitability – пригодность
TEXT
At first we should note that a pressure sensor measures pressure, typically of gases or liquids. The pressure here is taken as an expression of the force required to stop a fluid from expanding, and is usually stated in terms of force per unit area. So, a pressure sensor usually acts as a transducer. It generates a signal as a function of the pressure imposed. As the practice shows, such a signal is electrical in 80 cases of 100.
Pressure sensors are used for control and monitoring in thousands of everyday applications. They can also be used to indirectly measure other variables such as fluid or gas flow, speed, water level, and altitude. These devices can alternatively be called pressure transducers, pressure transmitters, pressure senders, pressure indicators or manometers among other names.
There is also a category of pressure sensors that are designed to measure in a dynamic mode for capturing very high speed changes in pressure. Example applications for this type of sensor would be in the measuring of combustion pressure in an engine cylinder or in a gas turbine. These sensors are commonly manufactured out of piezoelectric materials such as quartz.
Some pressure sensors, such as those found in some traffic enforcement cameras, function in a binary (on/off) manner, i.e., when pressure is applied to a pressure sensor, the sensor acts to complete or break an electrical circuit. These types of sensors are also known as a pressure switch.
Pressure sensors can be classified in terms of pressure ranges they measure, temperature ranges of operation, and most importantly the type of pressure they measure. Thus, in terms of pressure type, they can be divided into five categories.
The first category includes absolute pressure sensors. They measure the pressure relative to perfect vacuum pressure (0 PSI or no pressure). Atmospheric pressure, as compared, makes 14.7 PSI at sea level with reference to vacuum.
The category of gauge pressure sensors is used in different applications because its devices can be calibrated to measure the pressure relative to a given atmospheric pressure at a given location. A tire pressure gauge is an example of gauge pressure indication. When the tire pressure gauge reads 0 PSI, there is really 14.7 PSI (atmospheric pressure) in the tire.
Specialists utilize a vacuum pressure sensor to measure pressure less than the atmospheric pressure at a given location. This item has the potential to cause some confusion as industry may refer to a vacuum sensor as one which is referenced to either atmospheric pressure (i.e. measure negative gauge pressure) or relative to absolute vacuum.
Differential pressure sensors measure the difference between two or more pressures introduced as inputs to the sensing unit, for instance, measuring the pressure drop across an oil filter. Differential pressure is also used to measure flow or level in pressurized vessels.
The fifth category includes sealed pressure sensors. The devices are the same as the gauge pressure sensors except that they are previously calibrated by manufacturers to measure pressure relative to sea level pressure.
It should be also noted that pressure sensors can vary drastically in technology, design, performance, application suitability and cost. A conservative estimate shows that there were over 50 technologies and at least 300 companies making pressure sensors worldwide at the end of 2010.
Comprehension
Exercise 1.True or false?
1) Some pressure sensors may function in a binary manner.
2) Differential pressure sensors measure pressure less than the atmospheric pressure at a given location.
3) All pressure sensors measure pressure of gases and liquids only.
4) No pressure means the same as the perfect vacuum pressure.
5) Pressure sensors can never be used to indirectly measure any other variables.
6) A pressure transducer is not the same as a pressure sender.
7) The pressure is usually stated in terms of force per unit area.
8) A pressure sensor generates a signal as a function of the pressure imposed.
9) There are over 15 technologies and at least 30 companies making pressure sensors worldwide nowadays.
10) Differential pressure is used to measure flow or level in pressurized vessels.
Exercise 2.Complete the sentences using the correct words from the text:
1) The pressure is taken as an … of the … required to stop a fluid from ….
2) Specialists utilize a … pressure sensor to measure pressure less than the … pressure at a … location.
3) A … pressure gauge is an example of … pressure indication.
4) Pressure sensors can vary … in technology, design, …, and application ….
5) In terms of … type, pressure … can be divided into … categories.
6) The … of gauge pressure … is used in different ….
7) Atmospheric pressure makes … PSI at … level with reference to ….
8) … sensors are used for control and … in thousands of … applications.
Vocabulary
Exercise 3.Give the English or Russian equivalents for the following word combinations:
Разность давлений; to measure flow or level in pressurized vessels; физические параметры, измеряющиеся в зависимости от давления окружающей среды; to measure pressure relative to sea level pressure; опломбированный датчик давления; force per unit area; уловить изменение очень высоких скоростей; relative to absolute vacuum; давление сгорания в цилиндре двигателя моторной лодки; the potential to cause some confusion.
Exercise 4.Match the words with their meanings:
| 1) pressure | a) to determine or correct the scale of a graduated instrument |
| 2) gauge | b) used to close a thing tight to prevent leaks |
| 3) to monitor | c) surface parallel to the horizon with reference to its height |
| 4) to calibrate | d) force on or against or influence on something |
| 5) perfect | e) space completely empty of substance or gases |
| 6) sealed | f) any of a variety of measuring instruments |
| 7) vacuum | g) complete with everything needed |
| 8) level | h) to be aware of the state of a system |
Exercise 5.Translate from Russian into English:
1) Датчик давления – это устройство, физические параметры которого изменяются в зависимости от давления измеряемой среды. 2) Основным отличием одних измерительных приборов от других является точность регистрации давления, которая зависит от преобразования давления в электрический сигнал. 3) В отличие от датчика давления, манометр – это прибор, предназначенный для измерения давления, а не для его преобразования. 4) Показания манометра, которые могут быть считаны с его шкалы или дисплея, зависят от давления. 5) Датчики давления в камерах дорожной полиции США и Канады основаны на принципе использования реле давления. 6) Чувствительные элементы датчиков базируются на принципе измерения деформации резисторов, припаянных к титановой мембране, которая деформируется под действием давления. 7) Если бы управление статистики не проводило различные промышленные исследования, у нас не было бы информации о количестве и местоположении компаний, которые занимаются производством датчиков давления. 8) Датчики разности давлений могут помочь измерить давление в топливных насосах и масляных фильтрах. 9) Под вакуумом мы понимаем среду, которая содержит газ при давлениях значительно ниже атмосферного. 10) Датчики давления могут использоваться для непрямого измерения таких переменных величин, как уровень воды, скорость потока нефти или газа, а также высота полёта.
Exercise 6.Make up the summary of the text and write its annotation.
Discussion
Exercise 7.Work in pairs or in small groups. Share in the discussion. Use the following questions as prompts:
1) What are the functions of a pressure sensor?
2) Could you state all the names used instead of the term “pressure sensor?”
3) What is the goal of a dynamic mode measurement?
4) Could you give the definition of a pressure switch?
5) How many categories of pressure sensors do you know? Name them.
6) What is 0 PSI?
7) Where can specialists use a vacuum pressure sensor?
8) What is the difference between the first and the fifth categories of pressure sensors?
9) What was the world-wide volume of pressure sensors production at the end of 2010?
LESSON 6
MICROCONTROLLERS
Lexical units:
integrated circuit – интегральная схема
processor core – ядро процессора
embedded – встроенный
remote control – пульт дистанционного управления
appliances – электроприборы (бытовые)
pipe-line – конвейер
assembly shop – сборочный цех
instrument-making industry – приборостроение
clock rate – тактовая частота
consumption – расход, потребление
to retain – поддерживать, сохранять
interrupt – (здесь) сигнал прерывания
light-emitting diode – светоизлучающий диод
custom – обычный, стандартный
interrupt service routine = interrupt handler – обработчик прерывания
sequence – последовательность, ряд команд
overflow – переполнение
communication link – канал связи
to halt – останавливать
on-chip – встроенный в чип
compiler – компилирующее устройство или программа
assembler – транслятор
field-alterable – программируемый в полевых условиях
erasable – стираемый
TEXT
An item we know as a microcontroller is a small computer on a single integrated circuit containing a processor core, memory and programmable input/output peripherals. Sometimes, in technical literature, it may be abbreviated as μC, uC or MCU. Microcontrollers are designed for embedded applications, in contrast to microprocessors used in personal computers or other general purpose applications.
Microcontrollers are frequently used in automatically controlled products and devices, such as automobile engine control systems, implantable medical devices, remote controls, office machines, appliances, power tools, and toys as well as in transporters, pipe-lines, assembly shops, etc. By reducing the size and cost compared to a design that uses a separate microprocessor, memory, and input/output devices, microcontrollers make it economical to digitally control even more devices and processes. Mixed signal microcontrollers integrating analog components needed to control non-digital electronic systems, are common in the instrument-making industry.
Some microcontrollers may operate at clock rate frequencies as low as 4 kHz, for low power consumption (milliwatts or microwatts). Here, under the clock rate we understand the rate in cycles per second. Such microcontrollers generally have the ability to retain functionality while waiting for an event such as a button press or other interrupt. Power consumption while sleeping (CPU clock and most peripherals off) may be just nanowatts, making many of them well suited for long lasting battery applications. Other microcontrollers may need to act more like a digital signal processor, with higher clock speeds and power consumption.
The majority of microcontrollers in use today are embedded in other machinery, such as automobiles, telephones, appliances, and computer peripherals. These are called embedded systems. While some of them are very sophisticated, many have minimal requirements for memory and program length, with no operating system, and low software complexity. Typical input and output devices include switches, relays, solenoids, light-emitting diodes (LEDs), small or custom LCD displays, radio frequency devices, and sensors for data such as temperature, humidity, light level. Embedded systems usually have no keyboard, screen, disks, printers, or other recognizable I/O devices of a PC, and may use no human interaction devices.
Microcontrollers must provide real time (predictable, though not necessarily fast) response to events in the embedded system they are controlling. When certain events occur, an interrupt system can signal the processor to suspend processing the current instruction sequence and to begin an interrupt service routine (ISR, or “interrupt handler”). The ISR will perform any processing required based on the source of the interrupt before returning to the original instruction sequence. Possible interrupt sources are device dependent, and often include events such as an internal timer overflow, completing an analog to digital conversion, a logic level change on an input such as from a button being pressed, and data received on a communication link. Where power consumption is important as in battery operated devices, interrupts may also wake a microcontroller from a low power sleep state where the processor is halted until required to do something by a peripheral event.
Finally, we should mention microcontroller programs. They must fit in the available on-chip program memory, since it would be costly to provide a system with external memory. Compilers and assemblers are used to convert high-level language and assembler language codes into a compact machine code for storage in the microcontroller’s memory. Depending on the device, the program memory may be permanent, read-only memory that can only be programmed at the factory, or program memory may be field-alterable flash or erasable read-only memory.
Comprehension
Exercise 1.True or false?
1) Typical input and output devices include switches, relays, solenoids, etc.
2) Interrupts must provide real time response to events in the embedded system they are controlling.
3) A number of microcontrollers may operate at clock rate frequencies as low as 14 kHz.
4) A microcontroller is a small microprocessor on a single integrated circuit.
5) Sometimes microcontrollers may need to act more like a digital signal processor.
6) Microcontrollers are rarely used in automatically controlled devices.
7) Compilers are used to convert high-level language codes into a compact machine code.
8) Many embedded systems have maximal requirements for their memory and program length.
9) Microprocessors are used in PCs and other general purpose applications.
10) A logic level change on an input may be caused by a button pressure.
Exercise 2.Complete the sentences using the correct words from the text:
1) The … of microcontrollers in use today are … in other ….
2) Mixed … microcontrollers integrating … components needed to control …-… electronic systems, are common in the …-… industry.
3) Interrupts may also wake a … from a … power … state.
4) Under the … rate we understand the … in cycles per ….
5) Embedded … usually have no …, screen, disks, printers, or other … input-output devices.
6) The … will perform any … required based on the source of the … before returning to the original … sequence.
7) … interrupt sources often include events such as an internal timer … and completing an … to … conversion.
8) … consumption while sleeping may be just …, making many of them well suited for long lasting … applications.
Vocabulary
Exercise 3.Give the Russian or English equivalents for the following word combinations:
Recognizable I/O devices; программируемый в полевых условиях микроконтроллер; ability to retain functionality; встроенная в чип компилирующая программа; logic level change; устройство со стираемой памятью; to signal the processor to suspend processing the current instruction sequence; микроконтроллер, использующийся как устройство для цифровой обработки сигнала; high-level language and assembler language codes; стандартные светоизлучающие диоды, используемые в приборостроении.
Exercise 4.Match the words with their meanings:
| 1) diode | a) electrochemical cell to produce electricity |
| 2) memory | b) device that measures a physical quantity and converts it into a signal |
| 3) compiler | c) set of interacting or independent components forming an integrated whole |
| 4) button | d) device attached to a host computer, but not part of it |
| 5) peripheral | e) switch to control a machine or a process |
| 6) system | f) computer program to transform codes written in programming languages |
| 7) sensor | g) ability to store, retain, and recall data |
| 8) battery | h) two-terminal electronic component |
Exercise 5.Translate from Russian into English:
1) Микроконтроллер – это микросхема, предназначенная для управления электронными устройствами. 2) В современных микроконтроллерах используются мощные вычислительные устройства с широкими возможностями, построенные на одной микросхеме вместо целого набора. 3) При проектировании микроконтроллеров приходится соблюдать баланс между размерами и стоимостью с одной стороны и гибкостью и производительностью с другой. 4) Существует огромное количество микроконтроллеров, которые отличаются размером и видом встроенной памяти, набором периферийных устройств, а также типом корпуса и материалом, из которого он изготовлен. 5) Если бы производители не принимали во внимание ограничения в цене и энергопотреблении, это способствовало бы тому, что тактовая частота микроконтроллеров стала бы чрезвычайно высокой. 6) Программирование контроллеров обычно осуществляется на языке ассемблера, хотя существуют компиляторы и для других языков. 7) Специальные программы для персональных компьютеров, имитирующие работу микроконтроллера, используются для обнаружения, локализации и устранения ошибок. 8) На современном этапе развития приборостроение сделало доступным использование микроконтроллеров в сборочных цехах и на конвейерах, оборудованных соответствующим программным обеспечением. 9) Упрощённый набор команд (reduced instruction set) позволяет микроконтроллерам выполнять большинство инструкций за один такт, что обеспечивает высокое быстродействие даже при низкой тактовой частоте. 10) Микроконтроллер может иметь встроенную энергонезависимую память для хранения программы и данных.
Exercise 6.Make up the summary of the text and write its annotation.
Discussion
Exercise 7. Work in pairs or in small groups. Share in the discussion. Use the following questions as prompts:
1) What is a microcontroller? How can it be abbreviated?
2) Where are they usually applied?
3) What type of microcontrollers is common in the instrument making?
4) Why is the clock rate important in microcontrollers industry?
5) What units are used to measure microcontrollers power consumption?
6) How can you characterize an embedded system?
7) What is the function of an interrupt service routine?
8) Could you describe the principle of interaction between an interrupt and a microcontroller?
9) What types of microcontroller programs do you know?
LESSON 7