Electronics System Design Lab Viva Questions and Answers

Question No. 01: What is FM?
Answer: In telecommunications and signal processing, frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. (Compare with amplitude modulation, in which the amplitude of the carrier wave varies, while the frequency remains constant.)

Question No. 02: Define microprocessor
Answer: A silicon-chip that contains a CPU. In the world of personal computers, the terms microprocessor and CPU are used interchangeably. At the heart of all personal computers and most workstations sits a microprocessor. Microprocessors also control the logic of almost all digital-devices, from clock radios to fuel-injection systems for automobiles.

Question No. 03: What is DSP?
Answer: Digital signal processing (DSP) refers to various techniques for improving the accuracy and reliability of digital communications. The theory behind DSP is quite complex. Basically, DSP works by clarifying, or standardizing, the levels or states of a digital signal.

Question No. 04: Define AWGN.
Answer: AWGN-Additive White Gaussian Noise. It’s the natural noise added in the system.
Correlators are used to remove the noise. Equalizers are used to remove the ISI, in the receiver.

Question No. 05: Define Voltage regulator.
Answer: A voltage regulator is designed to automatically maintain a constant voltage level. A voltage regulator may be a simple “feed-forward” design or may include negative feedback control loops. It may use an electromechanical mechanism, or electronic components.

Question No. 06: What is AM?
Answer: Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. In amplitude modulation, the amplitude (signal strength) of the carrier wave is varied in proportion to the waveform being transmitted. That waveform may, for instance, correspond to the sounds to be reproduced by a loudspeaker, or the light intensity of television pixels. This technique contrasts with frequency modulation, in which the frequency of the carrier signal is varied, and phase modulation, in which its phase is varied.

Question No. 07: What is an instrumentation amplifier?
Answer: An instrumentation (or instrumentational) amplifier is a type of differential amplifier that has been outfitted with input buffer amplifiers, which eliminate the need for input impedance matching and thus make the amplifier particularly suitable for use in measurement and test equipment.

Question No. 08: Define Timer.
Answer: The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation, and oscillator applications. The 555 can be used to provide time delays, as an oscillator, and as a flip-flop element. Derivatives provide up to four timing circuits in one package.

Question No. 09: State the difference between AC and DC voltage.
Answer: In direct current (DC), the electric charge (current) only flows in one direction. Electric charge in alternating current (AC), on the other hand, changes direction periodically. The voltage in AC circuits also periodically reverses because the current changes direction.

Question No. 10: Define modulation.
Answer: In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted.

Question No. 11: Define microcontroller
Answer: A microcontroller (sometimes abbreviated μC, uC or MCU) is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals.

Question No. 12: Define voltage controller?
Answer: A voltage controller, also called an AC voltage controller or AC regulator is an electronic module based on either Thyristors, TRIACs, SCRs or IGBTs, which converts a fixed voltage, fixed frequency alternating current (AC) electrical input supply to obtain variable voltage in output delivered to a resistive load.

Question No. 13: What is PCB?
Answer: A printed circuit board (PCB) mechanically supports and electrically connects electronic components using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate.

Question No. 14: What is the purpose of using data modem?
Answer: Short for modulator-demodulator. A modem is a device or program that enables a computer to transmit data over, for example, telephone or cable lines. Computer information is stored digitally, whereas information transmitted over telephone lines is transmitted in the form of analog waves.

Question No. 15: Define Amplifier.
Answer: An electronic device for increasing the amplitude of electrical signals, used chiefly in sound reproduction a device consisting of an amplifier combined with a loudspeaker and used to increase the volume of the sound produced by electric guitars and other musical instruments.

Question No. 16: What is SCR?
Answer: Thyristors or silicon controlled rectifiers; SCR are found many uses in electronics, and in particular for power control. These devices have even been called the workhorse of high power electronics. Thyristors are able to switch large levels of power are accordingly they used in a wide variety of different applications. Thyristors even finds uses in low power electronics where they are used in many circuits from light dimmers to power supply over voltage protection.

Question No. 17: What is ZIGBEE?
Answer: ZIGBEE is a IEEE 802.15.4 based specification for a suite of high-level communication protocols used to create personal area networks with small, low-power digital radios.

Question No. 18: Define various modes of operation of timer.
Answer: The 555 has three main operating modes, Monostable, Astable, and Bistable. Each mode represents a different type of circuit that has a particular output.
Astable mode, Bistable Mode (or Schmitt Trigger), Monostable mode.

Question No. 19: Define signal sampling
Answer: In signal processing, sampling is the reduction of a continuous signal to a discrete signal. A common example is the conversion of a sound wave (a continuous signal) to a sequence of samples (a discrete-time signal).
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