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).