134. For fast communication, which of the following requirements must be met?
A. Large bandwidth
B. High S/N ratio
C. High channel capacity
D. None of the above
135. Broadband long distance communication was originally made possible by the advent of
A. telegraph cable
B. geostationary satellites
C. H.F. radio system
D. repeater amplifie
136. With reference to 'Telex' which of the following statements is correct?
A. It is a telegraph service between various subscribers
B. It is telephone service between various subscribers
C. It is a television service between various subscribers
D. It is a teleprinter service between various subscribers
137. Teleprinter code is unit code.
A.1
B.4
C.6
D. 7 -5-
138. Which of the following TV systems is adopted in India?
A. NTSC system
B. CCTv system
C. PAL system
D. None of the above
139. In communication receivers the fidelity is provided by
A. audio stage
B. detector range
C. mixer stage
D. all of the above
140. Due to which of the following reasons radar detection is limited to line of sight?
A. Short wavelengths are used
B. Long wavelengths are used
C. Curvature of the earth
D. the waves are not reflected by the ionosphere
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