537 questions and answers
Define SNR and Noise Figure. Why is the noise performance of the first stage of a cascade receiver so important? If each stage of a two – stage cascade amplifier has a gain of 10 dB and noise figure of 10 dB, calculate the total noise figure in dB.
In the communication systems, the comparison of signal power with the noise power at the same point is important, to ensure that the noise at that point is not excessively larger. It is defined as the ration of the signal power to the noise power at the same point.
Calculate the SNR at the output of a synchronous SSB-SC demodulator.
The receiver of an SSB-SC system is similar to that of or DSB-SC system for synchronous detection except for the fact that the bandwidth of the BPF of SSB-Sc receiver should be one- half of the required for DSB-SC.
An amplifier operating over the frequency range from 8 MHz to 20 MHz has a 10 kΩ input resistor. What is the r.m.s noise voltage at the input to this amplifier if the ambient temperature is \({27}^0C\)?
Given that, \(k=Boltzmann^\prime s constant=1.38\times{10}^{-23}\frac{Joules}{Kelvin}\)
What is Carson’s rule? Explain it.
Carson’s rule provides a thumb formula to calculate the bandwidth of a single tone wideband FM.
Explain the terms selectivity, sensitivity and fidelity of receiver.
The selectivity of a receiver is defined as the ability to accept a given band of frequencies and reject all other unwanted frequencies is called its selectivity. It also express the attenuation that the receiver offers to signal at frequencies adjacent to the one to which it is tuned.
What do you mean by thermal and white noise?
The thermal noise also known as Johnson noise. The free electrons within a conductor are always in random motion. This random motion is due to the thermal energy received by them. The distribution of this free electrons within a conductor at a given instant of time is not uniform.
Draw and explain the square – law modulator.
The device that generates an amplitude modulated wave is called an amplitude modulator. In this method, the linear device that will be used is a normal P-N junction diode.
Derive the expression for overall noise figure of a cascaded system.
The noise facto can be expressed in term of decibels. The representation of noise factor in decibel is known as noise figure. The noise figure \(F_{dB}=10logF\)
What is angle modulation?
In exponential modulation the angle of the carrier is varied in according with the baseband signal. For this reason, exponential modulation is also referred to as angle modulation.
Derive the relationship between modulation index and modulated signal amplitude for sinusoidally modulated DSB-TC signal
Let the modulated AM signal \(s\left(t\right)=\left[A_c+A_mx\left(t\right)\right]cos2\pi f_ct\) ……………..... (1) \({s\left(t\right)=A}_c\left[1+\frac{A_m}{A_c}x\left(t\right)\right]cos2\pi f_ct\)
MindStudy - a preparation hub for all the students. The goal is to make it easier for pupils to get better grades on exams.
Copyright © 2025 MindStudy
A product by Shunya Intelliware Solution
(Registered under MSME Uddyam)