126. A noiseless 3 kHz channel can't transmit binary bit at the rate
127. In an AM wave the carrier and one of the side bands is suppressed. If m = 1, the percentage saving in power is
128. Assertion (A): An electronic tuner uses varactor diodeReason (R): The capacitance of a varactor diode depends on the magnitude of reverse bias.
129. 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
130. In a tape recorder the output from RF oscillator is given to
131. A + 1.9 lens has a focal length of 25 mm. The diameter of lens is about
132. Which of the following terms are applicable to troposcatter propagation?
133. 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
134. In TV scanning sequence of lines is
135. Which of the following microphones works on the principle of Faraday's law?
136. In a CE amplifier connection, the emitter is at ground potential for
137. The Mauryan dynasty was overthrown by?
138. Directive gain is
139. Which of the following sampling frequencies is considered adequate in voice telephony?
140. In equally tampered scale, frequency of each tone equals the frequency of lower adjacent tone multiplied by
141. 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
142. 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
143. Which of the following microphones is used as a standard for calibration?
144. The reactance of coupling capacitor for AC signals in an amplifier, should be
145. 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
146. Resonant circuits are used in
147. Linear diode detector utilizes
148. In the equivalent circuit of a moving coil cone type loudspeaker, the mass of the moving system is represented by
149. Assertion (A): In India we use CCIR-B standardReason (R): Video signals are frequency modulated.