Q. If f is frequency and d is distance, path attenuation a between isotropic antennas is given by

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Q. If the transmitted pulse power of a radar is Pt (peak value) and the antenna is isotropic, the power density at a distance r is

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Q. In delta modulation, the output signal to quantization noise ratio S0/Nq is (N is the number of bits)

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Q. If B is channel bandwidth, S is signal power and N is the total noise within the channel bandwidth, the channel capacity C of a white band limited gaussian channel is

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Q. For an RC low pass filter, the relation between noise bandwidth BN and 3-dB bandwidth B3dB is

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Q. The block diagram of AM transmitter in which high level modulation is used as shown in figure. The block X could be

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Q. When E1, E2, E3 etc. are the simultaneous modulating voltages, then the total modulating voltage Et will be

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Q. The constellation diagram of a modem has four states as shown in the figure given below. What is the bit rate of this modem?

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Q. What is the RF amplifier plate voltage when the audio-modulating voltage is +600 V?

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Q. If carrier power is P and amplitude modulation index is m, the total power after modulation is

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Q. In figure the output v(t) is

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Q. Efficiency of general AM signal with em = E₁ cos ω₁t + E₂ cos ω₂ tj ec = Ec cos ωct; E₁ cos ω₁t with modulation index m₂ is __________ .

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Q. Each of the following equation expressing decibel gain is correct except

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Q. Waves travel on each of the line configurations in figure. In which case would the radiation be maximum

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Q. The figure shows a simple detector circuit for amplitude modulated wave v(t) = (1 + m cos ωmt) cost ωct. If the detector is to follow the envelope of modulated wave at all times the extent of modulation m must be less than or equal to m0 where m0 is given by equation

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Q. In figure the output v(t) is

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Q. If Pk be the probability of the message to be received or transmitted, then the amount of information (Ik) associated, in bits, will be

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Q. The ratio given by below equation for 100% amplitude modulation with identical total transmitted power (mf is modulation index of FM) is

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Q. The power density spectrum of noise voltage at the input of a network is Sni and that at the output of the network is Sno. If transfer function of network is H(ω), the corresponding noise figure is

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Q. The modulation index of an AM wave is measured using a CRO. The waveform is as shown in figure, the modulation index is nearly

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