55801. An AM signal and a narrowband FM signal with identical carriers, modulating signals and modulation index of 0.1 are added together. The resultant signal can be closely approximated by
55802. The equation v(t) = A cos [ωct + φ(t)] where A and ωc are constant and φ(t) is a function of base signal represents Phase modulationAmplitude modulationAngle modulationFrequency modulation Which of the above are true?
55803. An FM signal with deviation δ is passed through mixer. Its frequency is reduced five fold. The deviation in output of mixer is
55804. The total number of channels allotted for cellular telephone is
55805. The F.T. of {e-1 ∪(t)} is equal to . Therefore
is
55806. Sound waves are electromagnetic waves.
55807. In major diatonic musical scale, an octave is divided into
55808. The bandwidth of DSB suppressed carrier modulation system when the modulating frequency varies between 500 Hz and 5 kHz is
55809. The filter circuit for feeding a wooffer has
55810. The Hilbert transform of cos ω1t + sin ω2t is
55811. In ionosphere incidence angle is 60°. The maximum usable frequency fm is equal to
55812. The generally used value of EHV supply in TV receivers is
55813. The number of channels available in MF band (300 kHz - 3 MHz) for AM modulating signal of 20 kHz is
55814. The function of blend control in stereo system is
55815. The output resistance of a microphone is 20 ohms. It is to feed a line of impedance 320 ohms. To ensure maximum power transfer, the turn ratio of transformer is
55816. In a reactance FET, gm = 9 x 10-3 Siemens, gate to source resistance is one-ninth of reactance of gate to drain capacitor and frequency is 4 MHz. The capacitive-reactance is
55817. Audio cassettes used in household tape recorders have a width of
55818. The receiver of a pulsed RADAR can detect signal power in the order of
55819. In a 100% amplitude modulated signal, the power in the upper sideband when carrier power is to be 100 W and modulation system SSBSC, is
55820. Which camera tube has highest dark current?
55821. If a sound wave has a frequency of 50 Hz, the wavelength is
55822. Skin depth at 1000 MHz in comparison with that at 500 MHz is
55823. Consider the following Generation of SSB signalsDesign of minimum phase type filtersRepresentation of band pass signals Which of the above applications is Hilbert transform used?
55824. The dc voltage on plate modulated class C amplifier is 8 kV. If the peak modulating voltage is 4 kV, the peak RF voltage delivered to load is
55825. In telephone systems the relation between load r , number of calls initiated during a specified interval λ and average duration of a call (h) is
55826. In a Vidicon camera tube
55827. In a CD the sampling frequency is nearly
55828. Consider the following statements about loop antenna It is suitable for direction finding applicationIt is a single turn or multiturn coil carrying RF currentThe loop is surrounded by a magnetic field everywhere perpendicular to the loop Which of the above statements are correct?
55829. Which of the following is present in both TRF receiver and superheterodyne receiver?
55830. The number of channels in a stereophonic system is
55831. When the carrier is unmodulated, a certain transmitter radiates 9 kW when the carrier is sinusoidally modulated the transmitter radiates 10.125 kW. The modulation index will be
55832. A signal x(t) = 100 cos (24p x 103t) is ideally sampled with a sampling period of 50 μ sec and then passed through an ideal low pass filter with cut off frequency of 15 kHz Which of the following frequencies are present at the filter output?
55833. A sinusoidal voltage of 2 kV peak value is amplitude modulated to give 20% modulation. The peak value of each side band term is
55834. Consider the following reasons for using antenna coupler To prevent illegal radiation of spurious frequenciesTo tune out reactive components of antenna impedanceTo have correct value of load impedance for transmitter. Which of the above are correct?
55835. Which of the following is true in a tape recorder?
55836. In a high speed modem the data rate handled is about
55837. Trinitron is a monochrome picture tube.
55838. The first pulse in a TV remote control is
55839. If the ratio of ac to dc load impedance of a diode detector is low, the result will be
55840. The minimum step size required for a Delta modulator operating at 36 samples/sec to track the signal (here u(t) is the unit step function) x(t) = 125t (u(t) - u(t - 1)) + (250 - 125t) (u(t - 1) - u(t - 2)) So that slope overload is avoided, would be
55841. An FM signal with a deviation δ is passed through a mixer, and has its frequency reduced 5 fold. The deviation in the output of the mixer is
55842. In PCM, if the number of quantization levels is increased from 4 to 64, then the bandwidth requirement will approximately be increased __________ times.
55843. A tweeter should be fed from the input through a
55844. The modulation index is, if fm = 500 Hz, Δf = 2.25 kHz
55845. If D is mouth diameter of a paraboloid reflector, its directivity is proportional to
55846. A noiseless 3 kHz channel can't transmit binary bit at the rate
55847. In an AM wave the carrier and one of the side bands is suppressed. If m = 1, the percentage saving in power is
55848. Assertion (A): An electronic tuner uses varactor diodeReason (R): The capacitance of a varactor diode depends on the magnitude of reverse bias.
55849. A superheterodyne receiver is to operate in the frequency range 550 kHz - 1650 kHz, with the intermediate frequency of 450 kHz. Let denote the required capacitance ratio of the local oscillator and I denote the image frequency (in kHz) of the incoming signal. If the receiver is tuned to 700 kHz, then
55850. In a tape recorder the output from RF oscillator is given to