Find out the expressions for the different components of electric and magnetic fields inside a rectangular waveguide for TE mode of propagation. Hence find out the expression for the guide wavelength and propagation constant.

In order to study transmission lines electromagnetically, one should know the laws governing time varying electromagnetic fields. The interaction between charges and their mutual energy is expressed in terms of four vectors E and B, D and H. The first pair defines the factor on a charge density ρ moving with vector v given by;

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A multi hole directional coupler is fed with single power of 2.8 mW at 10 GHz. The coupling factor is 3 dB and the directivity is better than 40 dB over X-band range. Find the distribution of power at all other ports.

The expression for coupling factor is

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The dominant mode TE₁₀ is propagated in a rectangular waveguide of dimensions a=6 cm, b=4 cm. The distance between two successive minima is 4.47 cm. Determine the signal frequency.

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When a dominant mode is propagating in an air filled rectangular waveguide, the guide wavelength for a frequency of 9 GHz is 4 cm. Calculate broad wall dimension of the guide.

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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 \(f_c=\frac{6\times{10}^8}{2\pi}=95.45MHz\)

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added 2 years ago

Write short notes on:

• Pre – emphasis and De – emphasis
• FDM (Frequency division Multiplexing)

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.

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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

• Modulation index
• Frequency present in the modulated signal
• Total transmission power

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)

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added 2 years ago

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.

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A carrier signal \(A_ccos\omega_ct\) is amplitude modulated by a message signal \(A_mcos\omega_mt\), where \(A_m<A_c\)

• Write down the expression for the modulated signal
• Write down the expression for carrier component and side band components.
• Draw the phasor diagram of the modulated signal.

\(s\left(t\right)=\left(A_c+A_mcos\omega_mt\right)cos2\pi f_ct\) ………….….. (1) Where \(m_a=\frac{\left|A_m\right|}{A_c}\) for all \(A_c\geq A_m\) and it is called modulation index.

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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).

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added 2 years ago