55901. An amplifier has an input resistance of 10 kΩ and the noise voltage is 10 μV. If two such resistances of 10 kΩ each are connected in series at the input, the total noise voltage is about
55902. Drugs used for treatment of leprosy are
55903. In a colour TV receiver the bandwidth of RF amplifier is
55904. An FM signal with a deviation is passes through the mixer, and has its frequency reduced five fold. The deviation in the output of the mixer is
55905. FSK is a system involving
55906. A 200 Hz sound wave is to be transmitted by a 1000 kHz radio wave using frequency modulation. The instantaneous frequency variation will be
55907. In a TV studios, flying spot scanner is a device for
55908. A broadcast radio transmitter radiates 5 kW when the modulation percentage is 60. How much of this is carrier power?
55909. A device has two resistances 300 Ω and 200 Ω respectively. The noise voltages due to these two resistance calculated separately are 5.38 μV and 4.38 μV respectively. When both of them are used together, the noise voltage will be
55910. The antenna diameter of a radar system is doubled. The maximum range will
55911. Which of the following microphones works on the piezoelectric effect?
55912. In PAL system weighting of R - Y and B - Y signals is done to
55913. In case of probability of the message is 1 to 16 then the information will be
55914. The saving of power in DSB-SC modulated at 80% is
55915. A total of 16 equally probable events exist. If it is required to select one out of them, the number of required bits is
55916. When modulation index of an AM wave is increased from 0.5 to 1, the transmitted power
55917. Quantizing error occurs in
55918. In audio cassettes the width of each recording track is
55919. The most commonly used transistor amplifier circuit is
55920. When energy is fed into open wire transmission line the energy may get dissipated due to
55921. Fourier series expansion of a real periodic signal with fundamental frequency is given by It is given that c3 = 3 + j5. then c-3 is
55922. Loudness control gives
55923. A mobile telephone has a range of about
55924. If transmitted power is 75 kW, the field strength at 30 km distance will be about
55925. In the television system in India, each frame is scanned
55926. Each kilometer of travel in electromagnetic radiation means a time delay of
55927. A video monitor is exactly similar to TV receiver.
55928. A RADAR can be used to
55929. In single tone AM modulation, the transmission efficiency for m = 1 is
55930. AM amplifier having noise figure of 20 dB and available power gain of 15 dB is followed by a mixer circuit having noise figure of 9 dB. The overall noise figure as referred to input in dB is
55931. Which one of the following is non-resonant antenna?
55932. Condyloma lata is seen in
55933. The efficiency of using a binary system for selection of 1 out of 13 equally probable events is
55934. The most suitable method for detecting a modulated signal g(t) = (3 to 6 cos 2p fmt) cos 2p fct is
55935. The time required for horizontal blanking is 16% of that for each horizontal line. If horizontal time is 63.5 μs, the horizontal blanking time for each line is about
55936. When the number of quantising levels is 16 in PCM, the number of pulses in a code group will be
55937. A message signal with bandwidth 10 kHz is lower sideband SSB modulated with carrier frequency fc1 = 106 Hz. The resulting signal is then passed though a narrow band frequency modulator with carrier frequency fc2 = 109 Hz. The bandwidth of the output would be
55938. In a PCM system, if the code word length is increased from 6 to 8 bits, the signal to quantization noise ratio improves by the factor.
55939. For 10 bit PCM system, the signal to quantization noise ratio is 62 dB. If the number of bits is increased by 2, then the signal to quantization noise ratio will
55940. The video heads, in VCR, feed the other circuit
55941. A high pulse repetition frequency in a radar
55942. In PCM, the biggest disadvantage as compared to AM is
55943. Which of the following microphones is the cheapest?
55944. The following are characteristic features of Port-wine stain EXCEPT
55945. If a line is terminated in characteristic impedance Z0, the input impedance measured at the input will be
55946. In a TV, the output from RF tuner is about
55947. 24 telephone channels, each band limited to 3.4 kHz, are to be time division multiplexed by using PCM, calculate the bandwidth of PCM system for 128 quantization levels and an 8 KHz sampling frequency
55948. A signal is sampled at 8 kHz and is quantized using 8 bit uniform quantizer. Assuming SNRq for a sinusoidal signal, the correct statement for PCM signal with a bit rate of R is
55949. Generally a VCR has
55950. A remote control of TV uses a 10 bit word. The maximum number of total commands it can transmit is