Electronics and Communication Engineering - Electronic Devices and Circuits

41.
A digital system is required to amplify a binary encoded audio signal. The user should be able to control the gain of the amplifier from a minimum to a maximum in 100 increments. The minimum number of bits required to encode, in straight binary is,
8
6
5
7
Answer: Option
Explanation:

Let 6 bit required = 26 = 64, which indicate 64 increment.

If 7 bit = 27 = 128, for 100 increment, 7 bit required.


42.
A 4 bit transistor register has output voltage of high-low-high-low. The binary number stored and its decimal equivalent are
0101 and 5
0101 and 10
1010 and 5
1010 and 10
Answer: Option
Explanation:

1010 in binary and 8 + 2 = 10 in decimal.


43.

Assertion (A): A demultiplexer cannot be used as a decoder

Reason (R): A multiplexer selects one of many outputs whereas a decoder selects on output corresponding to coded input.

Both A and R are correct and R is correct explanation of A
Both A and R are correct but R is not correct explanation of A
A is true, R is false
A is false, R is true
Answer: Option
Explanation:

Demux can be used as a decoder.


44.
Hexadecimal number F is called to octal number
15
16
17
18
Answer: Option
Explanation:

F = 15 in decimal notation = 17 in octal notation (8 + 7 = 15).


45.
A half adder can be used only for adding
1 s
2 s
4 s
8 s
Answer: Option
Explanation: