Q. During day time ionosphere can be considered to be consisting of

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Q. Baudot code is a six bit code.

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Q. PWM can be generated

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Q. Consider the following statements as regards SAW filter

1. The centre frequency is determined by the pitch of IDT comb shaped electrodes
2. The response can be modified shaping the overlap of comb electrodes
3. The response is maximum when acoustic wave has its wavelength equal to pitch
4. When a number of identical electrodes are arranged at the same pitch, the frequency characteristics of the filter is expressed by (sin x)/x

Which of the above statements are correct?

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Q. In telephone, the dial tone has a frequency of

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Q. Companding is used

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Q. For a good public address system the sound intensity at the farthest point should be at least

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Q. An ungrounded antenna near the ground

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Q. Reception through space wave is limited to line of sight distance.

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Q. A video transmission system transmits 625 picture frames per second. Each frame consist of a 400 x 400 pixel grid with 64 intensity levels per pixel. The data rate of the system is

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Q. Which of the following is a false statement about Armstrong modulation system?

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Q. Which one is digital modulation technique?

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Q. Since noise phase modulated FM wave, as the noise sideband frequency approaches the carrier frequency, the noise amplitude

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Q. Consider the following statements as regards DPSK and DEPSK

1. DPSK demodulator requires a device which operates at carrier frequency and provides a delay of bit time Tb
2. In DPSK, synchronous demodulation recovers the signal b(t) and the decoding of b(t) to generate d(t) is done at base band
3. In both DPSK and DEPSK errors always occur in pairs

Which of the above statements are correct?

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Q. An audio frequency of 5 kHz is translated to a radio frequency carrier of frequency 1 MHz and transmitted it to space through an antenna. The required height of antenna is

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Q. Pre-emphasis circuit is used

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Q. In which frequency range is the noise figure in a transistor minimum

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Q. In commercial FM Broadcasting, A radio station transmitting the signal at 98.3 MHz, it is

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Q. Which of following digital modulation technique?

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Q. A discrete zero memory information source has 40 symbols and each symbol is equally likely. The minimum number of bits required to code the source with uniform length code and entropy of the source are

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