ELECTRONICS AND COMMUNICATION ENGINEERING IMPORTANT MCQ-Microwave,EMFT,Communication Part-5

Q201 IF THE PEAK TRANSMITTED POWER IN A RADAR SYSTEM IS INCREASED BY A
FACTOR OF 16,THE MAXIMUM RANGE WILL BE INCREASED BY A FACTOR OF
 (a)2
 (b)4
 (c)8
 (d)16
 ans-2

Q202 IF THE ANTENNA DIAMETER IN RADAR SYSTEM IS INCREASED BY A FACTOR OF 4,THE MAXIMUM RANGE WILL BE INCREASED BY A FACTOR OF
 (a)root 2
 (b)2
 (c)4
 (d)8
 ans-c

Q203 IF THE RATIO OF THE ANTENNA DIAMETER TO THE WAVELENGTH IN A RADAR
SYSTEM IS HIGH THIS WILL RESULT IN(INDICATE THE FALSE STATEMENT)
 (a)large maximum range
 (b)good target discrimination
 (c)difficult target acqusition
 (d)incresed capture area
 ans-d

Q204 THE RADAR CROSSECTION OF A TARGET(INDICATE THE FALSE STATEMENT)
 (a)depends on the frequency
 (b)may be reduced by special coating of the target
 (c)depends on the aspect a target ,if this is nonospherical
 (d)is equal to the actual cross-sectional area for small targets
 ans-d

Q205 FLAT-TOPPED RECTANGULAR PULSE MUST BE TRANSMITTED IN A RADAR TO(INDICATE THE FALSE STATEMENT)
 (a)allow  a good minimum range
 (b)make the return echoes easier to distinguish from noise
 (c)prevent frequency changes in the magnetron
 (d)allow accurate range measurements
 ans-b

Q206 A HIGH PRF (INDICATE THE FALSE STATEMENT)
 (a)make the return echoes easier to distinguish from noise
 (b)make target tracking easier with conical scaning
 (c)increse the maximum range
 (d)have no effect on the range resolution
 ans-c

Q207 THE IF BW OF A RADAR RECEIVER IS INVERSALY PROPORTIONAL TO THE
 (a)pulse width
 (b)prf
 (c)pulse interval
 (d)square root of the peak transmitted frequency
 ans-a

Q208 A RETURN ECHO ARRIVES AFTER THE ALLOCATED PULSE INTERVAL
 (a)it will interfere with the operation of the transmitter
 (b)the receiver may be overloaded
 (c)it will not be received
 (d)the target will appear closer than it really is
 ans-d

Q209 AFTER A TARGET HAS BEEN ACQUIRED ,THE BEST SCANNING SYSTEM FOF TRACKING IS
 (a)nodding
 (b)spiral
 (c)conical
 (d)helical
 ans-c

Q210 IF THE TARGET CROSS SECTION IS CHANGING ,THE BEST SYSTEM FOR ACCURATE TRACKING IS
 (a)lobe switching
 (b)sequential switching
 (c)conical scanning
 (d)monopulse
 ans-d

Q211 THE BIGGEST DISADVANTAGE OF CW DOPPLER RADAR IS THAT
 (a)it does not give the target velocity
 (b)it does not give the target range
 (c)a transponder is required at the target.
 (d)it does not give the target position
 ans-b

Q212 THE A SCOPE DISPLAYS
 (a)the target position and range
 (b)the target range,but not position
 (c)the target position but not range
 (d)neither range nor position,but only velocity
 ans-b

Q213 THE DOPPLER EFFECT IS USED IN(INDICATE THE FALSE STATEMENT)
 (a)moving target plotting on the ppi
 (b)the mti system
 (c)fm radar
 (d)cw radar
 ans-a

Q214 THE COHO IN MTI RADAR OPERATES AT THE
 (a)intermediate frequency
 (b)transmitted frequency
 (c)received frequency
 (d)pulse repetition frequency
 ans-a

Q215 THE FUNCTION OF THE QURTZ DELAY LINE IN AN MTI RADAR IS TO
 (a)help in subtracting a complete scan from the previous scan
 (b)match the phase of the coho and the stalo
 (c)match the phase of the coho and the o/p  oscillator
 (d)delay a aweep so that the next sweep can be subtracted from it.
 ans-a

Q216 A SOLUTION TO THE “BLIND SPEED” PROBLEM IS TO
 (a)change the doppler frequency
 (b)vary the prf
 (c)use monopulse
 (d)use mti
 ans-b

Q217 INDICATE WHICH ONE OF THE FOLLOWING APPLICATIONS OR DISADVANTAGE OF RADAR BEACONS IS FALSE
 (a)target identification
 (b)navigation
 (c)very significant extension of the maximum range
 (d)more accurate tracking of enemy targets
 ans-d

Q218 COMPARED WITH OTHER TYPES OF RADAR ,PHASED ARRAY RADAR HAS THE FOLLOWING ADVANTAGES(INDICATE THE FALSE STATEMENT)
 (a)very fast scanning
 (b)ability to track and scan simultaneously
 (c)critical simplicity
 (d)ability to track many targets simultaneously.
 ans-c

Q219 INTERLACING IS USED IN TELEVISION TO
 (a)produce the illusion of motion
 (b)ensure that all the lines on the screen are scanned ,not merely the alternate ones
 (c)simplify the vertical sync pulse train
 (d)avoid flicker
 ans-d

Q220 THE SIGNALS SENT BY THE TV TRANSMITTER TO ENSURE CORRECT SCANNING IN THE RECEIVER ARE CALLED
 (a)sync
 (b)chroma
 (c)luminance
 (d)video
 ans-a

Q221 INDICATE WHICH OF THE FOLLOWING VOLTAGES IS NOT FOUND IN THE O/P STAGE OF A NORMAL MONOCHROME RECEIVER VIDEO DETECTOR
 (a)sync
 (b)video
 (c)sweep
 (d)sound
 ans-c

Q222 IN TELEVISION 4:3 REPRESENTS THE
 (a)interlace ratio
 (b)maximum horizontal defletion
 (c)aspect ratio
 (d)ratio of the two diagonals
 ans-c

Q223 EQUALIZING PULSE IN TV ARE SENT DURING
 (a)horizontal blanking
 (b)vertical blanking
 (c)the serrations
 (d)the horizontal retrace
 ans-b

Q224 THE FUNCTION OF THE SERRATIONS IN THE COMPOSITE VIDEO WAVEFORM IS TO
 (a)equalize the charge in the integrator before the start of vertical retrace
 (b)help vertical synchronisation
 (c)help horizontal synchronisation
 (d)simplify the generation of the vertical sync pulse
 ans-c

Q225 INDICATE WHICH OF THE FOLLOWING FREQUENCIES WILL NOT BE PRESENT IN THE O/P OF A NORMAL TV RECEIVER
 (a)4.5mhz
 (b)41.25mhz
 (c)45.75mhz
 (d)42.17mhz
 ans-a

Q226 THE VOLTAGE APPLIED TO THE PICTURE TUBE OF A TELEVISION RECEIVER IS FED IN
 (a)b/w grid and ground
 (b)to the yoke
 (c)to the anode
 (d)b/w grid and cathode
 ans-d

Q227 THE CIRCUIT THAT SEPARATES SYNC PULSES FROM THE COMPOSITE VIDEO WAVEFORM IS
 (a)the keyed agc amplifier
 (b)a clipper
 (c)an integrator
 (d)a differentiator
 ans-b

Q228 THE O/P OF THE VERTICAL AMPLIFIER APPLIED TO  THE YOKE IN A TV RECEIVER ,CONSISTS OF
 (a)direct current
 (b)amplified vertical sync pulses
 (c)a sawtooth voltage
 (d)a sawtooth current
 ans-d

Q229 THE HV ANODE SUPPLY FOR THE PICTURE OF A TUBE OF A RECEIVER IS GENERATED IN THE
 (a)main transform
 (b)vertical o/p stage
 (c)horizontal o/p stage
 (d)horizontal deflection oscillator
 ans-c

Q230 ANOTHER NAME FOR THE HORIZONTAL RETRACE IN A RECEIVER IS THE
 (a)ringing
 (b)burst
 (c)damper
 (d)flyback
 ans-d

Q231 THE SHADOW MASK IN A COLOUR PICTURE TUBE IS USED TO
 (a)reduce x-ray emission
 (b)ensure that each beam hits only one dots
 (c)increase screen brightness
 (d)provide degaussing for the screen
 ans-b

Q232 IN A TV RECEIVER ,THE COLOUR KILLER
 (a)cuts off the chroma stages during monochrome reception
 (b)ensure that no colour is transmitted to monochrome receiver
 (c)prevents colour overloading
 (d)makes sure that the colour burst is not mistaken for sync pulses,by cutting off reception during the back poarch
 ans-a

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CURRENT AFFAIRS QUIZ OF DAY-25 February-2017
ELECTRONICS AND COMMUNICATION ENGINEERING IMPORTANT MCQ-Microwave,EMFT,Communication Part-4

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