55851. A + 1.9 lens has a focal length of 25 mm. The diameter of lens is about
55852. Which of the following terms are applicable to troposcatter propagation?
55853. If the amplitude of the voltage is kept constant, but its frequency is raised to 6 kHz, the new deviation will be for the modulation index is, if fm = 500 Hz, Δf = 2.25
55854. In TV scanning sequence of lines is
55855. Which of the following microphones works on the principle of Faraday's law?
55856. In a CE amplifier connection, the emitter is at ground potential for
55857. The Mauryan dynasty was overthrown by?
55858. Directive gain is
55859. Which of the following sampling frequencies is considered adequate in voice telephony?
55860. In equally tampered scale, frequency of each tone equals the frequency of lower adjacent tone multiplied by
55861. A carrier is modulated by two modulating waves A and B having modulation indices of 0.6 and 0.8 respectively. The overall modulation index is
55862. A communication channel disturbed by additive white, Gaussian noise has a bandwidth of 4 kHz and SNR of 15. The highest transmission rate that this channel can support (in k bits/sec) is
55863. Which of the following microphones is used as a standard for calibration?
55864. The reactance of coupling capacitor for AC signals in an amplifier, should be
55865. 24 telephone channels, each band limited to 3.4 kHz are to be time division multiplexed using PCM. If sampling frequency is 10 kHz and number of quantization levels is 128, the required bandwidth of PCM is
55866. Resonant circuits are used in
55867. Auspitz sign is seen in
55868. Linear diode detector utilizes
55869. In the equivalent circuit of a moving coil cone type loudspeaker, the mass of the moving system is represented by
55870. Assertion (A): In India we use CCIR-B standardReason (R): Video signals are frequency modulated.
55871. CATV stands for
55872. Household tape recorders use
55873. A 400 W carrier is modulated to a depth of 75 percent. The total power in modulated wave will be
55874. A geostationary satellite
55875. A line has L = 0.8 µH/m and C = 32 pF/m. Z0 =
55876. A line has standing waves with a voltage maximum of 35 mV and minimum of 17.5 mV VSWR is
55877. For a bit rate of 8 kbps, the best possible values of the transmitted frequencies in a coherent binary FSK system are
55878. If luminance signal Y = 0.3 R + 0.59 G + 0.11 B, the hue of R - Y colour is
55879. Trap circuits used in video IF amplifier of colour TV are
55880. Sign of groove is seen in
55881. A 300 Hz sound wave of intensity 20 dB is transmitted by a 1500 kHz radio wave by frequency modulation. It is seen that instantaneous frequency varies between 1500.2 kHz and 1499.8 kHz, 300 times a second. If the intensity of sound wave is 100 dB.
55882. If the average power of radar transmitters is 2 kW and the peak power of the transmitter is 1000 kW, what will be the duty cycle?
55883. An analog signal is band limited to B Hz sampled at Nyquist rate and samples are quantized into 4 levels each with probability . The information rate is
55884. The HV supply to a TV receiver is 25 kV and the total beam current for the three electron guns is 2000 μA. The power handled by IHVT is
55885. Some advantages of optical fibre cables are small diameterImmunity to cross talk and EM interferenceLaser and LED modulation methods lend themselves ideally to digital operation Which of the above are correct?
55886. The contrast control in colour TV receiver is done by
55887. The requirements of carrier frequency are
55888. If N bits are lumped together to get an N-bit symbol, the possible number of symbols is
55889. The received signal frequency at any time of a super-heterodyne receiver having IF = 456 kHz is 1 MHz. The corresponding image signal is
55890. For an ideal 3000 Hz channel, Nyquist rate is
55891. Assertion (A): Electromagnetic waves in free space spread uniformly in all directions from a point sourceReason (R): Free space has no interference or obstacles.
55892. In the FM wave described by equation v = 15 sin (4 x 108 t + 3 sin 1100 t), the maximum frequency deviation is
55893. The radar cross-section of a target depends an
55894. Which is the following terms is used in the game of chess?
55895. A directional microphone gives an output of 0.5 mV whereas an omnidirectional one gives an output of 0.5 μV in the same position for the same sound pressure. The directivity of the directional microphone is
55896. If Eb, the energy per bit of a binary digital signal is 10-6 watt sec. and the one sided power spectral density of the white noise N0 = 10-5 W/Hz, then the output SNR of the matched filter is
55897. Consider the following statements about Rhombic antenna It is non resonantIt is a broad band antennaIt is ideally suited for HF transmission Which of the above are correct?
55898. Assertion (A): A composite video signal has synchronising pulses.Reason (R): It is necessary to synchronise the scanning process in the transmitter and receiver.
55899. Noise with uniform power spectral density of N0ω/Hz is passed through a filter H(ω) = 2 exp (-J ω ty) followed by an ideal low pass filter of bandwidth B Hz. The output noise power in watts is
55900. Assertion (A): In standing wave pattern, the nodes and anti nodes are separated by half wave-lengthReason (R): When line is terminated in resistance RL, the standing wave ratio is SWR = Z0/RL or RL/Z0