VIKRAM SARABHAI SPACE CENTER - TECHNICAL ASSISTANT ( ELECTRONICS AND COMMUNICATION ENGINEERING)- 2015
1. The output of the circuit will be of frequency
a) 125 Hz
b) 250 Hz
c) 375 Hz
d) 500 Hz
2. The number 149 in octal code is
a) 154
b) 178
c) 254
d) 225
3. Universal gates are
a) OR & AND gates
b) NOR & NAND gates
c) NOR & AND gates
d) NAND & OR gates
4. In full adder, there are
a) Two binary number inputs and two outputs
b) Three binary digit inputs and two binary outputs
c) Three binary digit inputs and three binary digit outputs
d) NAND & OR gates
5. The main advantage of PCM system is lower
a) Bandwidth
b) Power
c) Noise
d) None of these
6. To transmit N signals each band limited to fmHz by time division multiplexing will require a minimum bandwidth of
a) fm
b) 2fm
c) N fm
d) Fm /N
7. Automatic gain control is used
a) To maintain the tuning correct
b) To reduce the volume of loud passages of music
c) To increase the amplification at high frequencies
d) To maintain the same volume of output when stations of different strength are received
8. The rotor of an induction motor cannot run with synchronous speed because
a) Lenz’s law will be violated
b) Rotor torque will then be zero
c) Induction motor would become synchronous motor
d) Air function prevents it to do so.
9. Using negative feedback for improvements, which statement is false
a) Increased bandwidth
b) Increased noise
c) Decreased distortion
d) High input impedance but lowe output impedence
10. An amplifier has input impedance of 4 kohm and output impedance of 80 kohm. It is used in negative feedback circuit with 10% feedback. If open loop gain is 90, the closed loop input impedances are
a) 40 kohm and 8 kohm respectively
b) 4 kohm and 80 kohm respectinvely
c) 0.4 kohm and 800 kohmrespectively
d) 8 kohm and 160 kohm resopectively
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