101. If a sound wave has a frequency of 50 Hz, the wavelength is
102. Skin depth at 1000 MHz in comparison with that at 500 MHz is
103. 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?
104. 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
105. 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
106. In a Vidicon camera tube
107. In a CD the sampling frequency is nearly
108. 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?
109. Which of the following is present in both TRF receiver and superheterodyne receiver?
110. The number of channels in a stereophonic system is
111. 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
112. 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?
113. A sinusoidal voltage of 2 kV peak value is amplitude modulated to give 20% modulation. The peak value of each side band term is
114. 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?
115. Which of the following is true in a tape recorder?
116. In a high speed modem the data rate handled is about
117. Trinitron is a monochrome picture tube.
118. The first pulse in a TV remote control is
119. If the ratio of ac to dc load impedance of a diode detector is low, the result will be
120. 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
121. 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
122. In PCM, if the number of quantization levels is increased from 4 to 64, then the bandwidth requirement will approximately be increased __________ times.
123. A tweeter should be fed from the input through a
124. The modulation index is, if fm = 500 Hz, Δf = 2.25 kHz
125. If D is mouth diameter of a paraboloid reflector, its directivity is proportional to