Q. A single tone modulating signal Vm cos ωt modulates a carrier A cos ωct. The carrier power (modulated) and side band powers are respectively

View solution

Q. Modulation index of a AM wave is measured using oscilloscope. The display on the CRO is as shown in figure it can be concluded that

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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?

View solution

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

View solution

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

View solution

Q. In figure the output v(t) is

View solution

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 __________ .

View solution

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

View solution

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

View solution

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

View solution

Q. In figure the output v(t) is

View solution

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

View solution

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

View solution