| Que. 1 |
Compression in PCM refers to relative compression of |
| A |
|
higher signal amplitude |
| B |
|
lower signal amplitude |
| C |
|
lower signal frequencies |
| D |
|
higher signal frequencies |
|
| Que. 2 |
At a given probalility of error, binary coherent FSK is inferior to binary
coherent PSK by |
| A |
|
6 DB |
| B |
|
3 DB |
| C |
|
2 DB |
| D |
|
0 DB |
|
| Que. 3 |
the number of memory cycles required to execute the following 8085 instruction
(I) LDA 3000 H (II) LXI, FOF 1 H would be |
| A |
|
2 for (I) and 2 for (II) |
| B |
|
4 for (I) and 3 for (II) |
| C |
|
3 for (I) and 3 for (II) |
| D |
|
3 for (I) and 4 for (II) |
|
| Que. 4 |
(D)the speech signal is being sampled at the Nyquest rate |
| A |
|
the input to the modulator is essentially constant |
| B |
|
the modulator is going through slope overload |
| C |
|
the accumulator is in saturation |
| D |
|
the speech signal is being sampled at the Nyquest rate |
|
| Que. 5 |
Frequencies in UHF range propagate by means of |
| A |
|
ground waves |
| B |
|
sky waves |
| C |
|
space waves |
| D |
|
surface waves |
|
| Que. 6 |
In air a lossless transmission line of length of 50cm with L=10 micro.H/m
is operated at 25 mhz.Its electrical length is |
| A |
|
2.0m |
| B |
|
(lemda)m |
| C |
|
(pi)/2radian |
| D |
|
180 egree |
|
| Que. 7 |
In a twice wire transmission line in air. the adjacent voltage maximum
are at 12.5cm and 27.5cm the operating freq. is |
| A |
|
300mhz |
| B |
|
1Ghz |
| C |
|
2Ghz |
| D |
|
6.28Ghz |
|
| Que. 8 |
Two events A and B are stastically indepndent and mutually exclusive.
The probability P(AB) is: |
| A |
|
0 |
| B |
|
1 |
| C |
|
infinite |
| D |
|
none of these |
|
| Que. 9 |
A lossless line of 50 ohms is terminated in a load of 100 ohms resistive.The
VSWR is |
| A |
|
1:2.5 |
| B |
|
2:1 |
| C |
|
4:1 |
| D |
|
3:4 |
|
| Que. 10 |
Ques:short term fading in microwave communication links can be over come
buy |
| A |
|
incresing the transmitted power |
| B |
|
changing the antenna |
| C |
|
changing themodulation scheme |
| D |
|
diversity reception and transmission |
|
| Que. 11 |
FM broadcast band lies in |
| A |
|
VHF band |
| B |
|
UHF band |
| C |
|
SHF band |
| D |
|
HF band |
|
| Que. 12 |
Which one of the following microphones doesnot have a flat freq. response? |
| A |
|
carbon microphone |
| B |
|
condenser microphone |
| C |
|
Ribon microphone |
| D |
|
Crystal microphone |
|
| Que. 13 |
The intermediate freq. of the superhet receiver is 450khz if it is tuned
to 1200khz, the image freq. will be |
| A |
|
750khz |
| B |
|
900khz |
| C |
|
1600khz |
| D |
|
2100khz |
|
| Que. 14 |
Microwave link repeaters are typically 50 km apart in TV transmission
because |
| A |
|
of atmospheric attenuation |
| B |
|
of output power tube limitations |
| C |
|
microwave transmission is through surface wave whic attenuation faster |
| D |
|
of earth's curvature |
|
| Que. 15 |
The balance output the local oscillator noise at the input to the intermediate
freq. or to IF amplifier is superheterodyne receivers, the microwave
ckt used is |
| A |
|
balabced amplifier |
| B |
|
balabced isolator |
| C |
|
balabced phase shifter |
| D |
|
balabced microwave mixer |
|
| Que. 16 |
In a 100 line exchange with 10 first selectors,the number of line finders
required |
| A |
|
is 10 |
| B |
|
is 100 |
| C |
|
would depend upon the traffic flow |
| D |
|
is busy hour calling rate |
|
| Que. 17 |
A satellite carrying antenna system,transmitter,receiver and power supply
is known as |
| A |
|
geostationary satellite |
| B |
|
orbital satellite |
| C |
|
avtive satellite |
| D |
|
passive satellite |
|
| Que. 18 |
The smallest change in sound intensity that can be detected |
| A |
|
1dB |
| B |
|
3dB |
| C |
|
10dB |
| D |
|
20dB |
|
| Que. 19 |
At very high freq. earth acts as a |
| A |
|
dielectric |
| B |
|
conductor |
| C |
|
perfect conductor |
| D |
|
perfect dielectric |
|
| Que. 20 |
compading is used |
| A |
|
to protect small signal in PCM from quantizing distortion |
| B |
|
to overcome quantized noise in PCM |
| C |
|
to overcome the impulse noise |
| D |
|
none of these |