56251. Consider the following statements as regards IF in radio receivers If IF is too high, poor selectivity and poor adjacent channel rejection could resultIf IF is high, tracking difficulties increaseA very low IF makes selectivity too sharpAs IF is decreased, image frequency rejection becomes better Which of the above are correct?
56252. Audio-signal modulates a 125 MHz carrier, causing a frequency deviation of 5 kHz. The bandwidth of the narrowband FM signal is __________ kHz.
56253. Assertion (A): Radar gave birth to microwave technology.Reason (R): In radar systems very high frequencies give the most accurate results.
56254. A channel has a SNR of 7 and BW 4 kHz. Keeping the channel capacity (BPS) same, the BW is reduced to accommodate more channels. The SNR
56255. The output VR of the ratio detector is related with the output VF of similar Foster-Seeley discriminator as follows.
56256. In grid bias modulation system the power required for modulating amplifier
56257. In spread spectrum technique
56258. QAM stands for
56259. The bandwidth required for amplitude modulation is
56260. The smallest change in sound intensity that can be detected by human ear is __________ dB.
56261. Low frequency boost can be easily compensated by
56262. An MTI compares a set of received echos with those received during the previous sweep.
56263. If e = 10 sin(108 t + 3 sin 104 t) then the deviation is
56264. When a complex signals is used to frequency modulate a carrier, the resulting sideband distribution is
56265. Which of the following is the main advantage of PCM system?
56266. BPSK stands for
56267. If a dipole is meant for a frequency of 1 MHz, the length of each rod is about
56268. Consider the following statements:
In a radar system having a high value of the ratio (antenna diameter)/wavelength the maximum range is largegood target discrimination is achievedcapture area is increasedtarget acquisition is difficult Which of the above are correct?
56269. Assertion (A): The maximum range of a radar is proportional to fourth root of the peak transmitted pulse power.Reason (R): Radar signals are subjected twice to inverse square law.
56270. As EM waves travel in free space they get
56271. Cross talk is due to reception of portions of a signal from one channel into another.
56272. If there are M equally likely and independent messages and M = 2N where N is an integer, the information in each message is equal to
56273. A radar beacon is a small radar set having a receiver, a separate transmitter and an antenna.
56274. In the above case the total power in the modulated wave double sideband, suppressed carrier AM will be
56275. Brownian motion is
56276. In a TV studio the illuminance is about
56277. MEWS stands for
56278. Top loading in an antenna increases
56279. In a radar, the return echo arrives after the allocated pulse interval. Then
56280. The decoder for PAL system is
56281. CW Doppler radar is capable of giving accurate measurements of relative velocities.
56282. In the stabilized reactance modulators AFC system
56283. An antenna is 30 metre high. The frequency is 1 MHz. The radiation resistance is about
56284. Which of the following codes is based on BCD format?
56285. In a system using QASK and 4 bits to form a symbol, the required bandwidth is
56286. Each of the following statements regarding frequency modulation is true except
56287. Assertion (A): Radio transmission is by sky wavesReason (R): Waves having frequencies higher than 30 MHz penetrate the atmosphere and do not return to earth.
56288. During playback the take up reel is
56289. To avoid objectionable noise in a microwave TV link, the SNR should be about
56290. Foster Seeley discriminator uses a
56291. Which of the following statement about modulation is correct?
56292. Sound wave travels as
56293. FM signal can be generated by
56294. A planar array radar uses a high gain planar array antenna.
56295. Which of the following terms is not applicable to Yagi-Uda array?
56296. If transmission path, in PCM, is very long then
56297. If F(ω) is Fourier transform of f(t), then the Fourier transform of f(t) cos ωct is
56298. In a TV receiver the raster is normal but there is no sound and quality of picture is poor. The defective part is
56299. If the plate supply voltage for a plate modulated class C amplifier is E, the maximum plate cathode voltage could be almost as high as