(SEM VIII) THEORY EXAMINATION 2017-18 EMBEDDED SYSTEMS

SECTION A (Brief Explanation – Proper Paragraph Style)

Basic Structure of Embedded System
An embedded system consists of input devices, a processor, memory, and output devices. First, a sensor collects input from the environment. If the signal is analog, it is converted into digital form using an ADC. The processor then processes this data according to the programmed instructions stored in memory. Finally, the output is given to an actuator or display device. This structure allows the system to sense, process, and respond automatically.

Division of Embedded Systems
Embedded systems are divided based on size and complexity. Small-scale systems use simple microcontrollers and limited memory. Medium-scale systems use 16/32-bit controllers and may include RTOS. Large-scale systems are complex and use powerful processors with operating systems like embedded Linux. They can also be classified as standalone, real-time, or networked systems.

Sampling
Sampling is the process of converting a continuous analog signal into discrete values at regular time intervals. It allows analog signals to be processed digitally. Proper sampling ensures accurate representation of the original signal.

Signal and Its Types
A signal is a physical quantity that carries information. It can be analog, which is continuous in nature, or digital, which consists of discrete binary values (0 and 1). Embedded systems often convert analog signals into digital form for processing.

Signal Conditioning
Signal conditioning improves the quality of a signal before processing. It may involve amplification, filtering, or noise removal. This ensures accurate and reliable system performance.

Signal Processing
Signal processing refers to analyzing and modifying signals to extract useful information. In embedded systems, digital signal processing helps in filtering noise and improving signal quality.

Embedded Control
Embedded control means using embedded systems to automatically control machines or devices. For example, in a washing machine, the controller manages water level and timing without human intervention.

Fault and Its Types
A fault is an abnormal condition that disturbs normal system operation. It can be permanent, transient, or intermittent. Fault detection improves system reliability.

Formal Verification
Formal verification is a mathematical method used to prove that a system design is correct and error-free. It increases reliability, especially in safety-critical systems.

Embedded Processors
Embedded processors are specialized processors designed for specific tasks. Examples include microcontrollers, DSPs, ARM processors, ASICs, and FPGAs.

SECTION B (Brief but Clear)

Applications of Embedded Systems
Embedded systems are used in home appliances, automobiles, medical devices, industrial automation, and communication systems. They improve automation, efficiency, and reliability in daily life. For example, engine control systems in cars and ECG machines in hospitals depend on embedded technology.

RTOS Issues
A Real-Time Operating System ensures tasks are completed within deadlines. Major issues include task scheduling, priority management, memory handling, and interrupt control. In hard real-time systems, missing a deadline can cause serious failure.

SECTION C (Brief Explanation)

Characteristics of Embedded Systems
Embedded systems are task-specific, reliable, and resource-limited. They often operate in real time and consume low power. They must be cost-effective and efficient for practical applications.

Timing and Clocks
Timing is crucial in embedded systems because tasks must execute at correct intervals. System clocks synchronize operations, and watchdog timers detect failures. Accurate timing ensures reliable performance.

Communication Strategies
Embedded systems communicate using serial protocols like UART, SPI, and I2C, or network protocols like CAN and Ethernet. Proper communication ensures data transfer between devices.

Digitization Process (ADC to DAC)
Digitization starts with sampling an analog signal, converting it into digital form using ADC, processing it, and then converting it back to analog form using DAC if required.

Minimum Performance Criterion
It defines the lowest acceptable performance level during system faults. It ensures that even in failure conditions, the system continues to function safely.