41 questions and answers
What are the basic components of communication system? Which of the above components affect the signal most with noise, in a communication system?
The basic compos of communication systems are Transmitter Transmission path
Describe why modulation is necessary for communication.
Multiplexing: Multiplexing is the technique use for transmitting several information bearing signaler the same physical channel simultaneously. It is possible; if different type of base band signal is modulate by the different high ranges carrier frequency.
Find the carrier and modulating frequency, the modulation index and the maximum deviation of the FM wave presented by the voltage equation \(v=5sin\left(6\times{10}^8t+5sin1000t\right)\). What power will this FM wave dissipate across a 20Ω resistor?
Given that \(A_c=5V\), Resistance \(R=20\mathrm{\Omega}\) Carrier frequency \(f_c=\frac{6\times{10}^8}{2\pi}=95.45MHz\)
Write short notes on:
The noise power density at the demodulator output is increase with frequency. This means this the effect of noise increases with increase in frequency. This is unfortunately because, noise is strongest in the frequency range in which the signal is weakest.
A modulating signal is given by \(V_m=2sin\left(2\pi\times500t\right)\) amplitude modulates a carrier signal given by \(V_C=10sin2\pi\times{10}^6t\), Determine
The expression of Amplitude modulated signal is \(S\left(t\right)=\left[10sin2\pi\times{10}^6t+40sin\left(2\pi\times500t\right)sin2\pi\times{10}^6t\right]\) … (1)
State and prove the Parseval’s theorem for power.
The parseval’s theorem in analogous to the parseval’s power theorem. It states that the total energy of the signal(t) is equal to the sum of energies of the individual spectral components in the frequency domain.
A carrier signal \(A_ccos\omega_ct\) is amplitude modulated by a message signal \(A_mcos\omega_mt\), where \(A_m<A_c\)
\(s\left(t\right)=\left(A_c+A_mcos\omega_mt\right)cos2\pi f_ct\) ………….….. (1) Where \(m_a=\frac{\left|A_m\right|}{A_c}\) for all \(A_c\geq A_m\) and it is called modulation index.
Explain briefly the VSB-SC modulation
The block diagram for generation of VSB signal is shown in Fig. 17. The block diagram consists of incoming message signal \(x\left(t\right)\), carrier signal \(A_ccos2\pi f_ct\), balanced modulator and a Low Pass Filter (LPF).
Compare AM and NBFM.
AM stand for amplitude modulation. Bandwidth of the amplitude modulated signal is \(2f_m\), where \(f_m\) is the maximum modulating signal frequency. The mathematical expression of AM waveform is defined as
Considering a message signal \(e_m=E_mcos\omega_mt\) and carrier signal by \(e_c=E_csin\left(\omega_c+\theta\right)t\), find the expression of the resultant FM wave.
The general expression of FM signal is \(S\left(t\right)=E_csin\left(\omega_ct+\theta\right)\) \(S\left(t\right)=E_csin\left(\omega_ct+2\pi k_f\int_{0}^{t}{e_mdt}\right)\)
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)