#mano

Question

A digital circuit accepts a 3 bit number and generates an output equal to the cube of the input number. If the circuit is to be designed using a ROM with minimum hardware, the size of ROM is.

 

A) 8x6

B) 8x7

C) 8x8

D) 8x9

 

Comments

Mk Utkarsh Oh yes :P

arvin It's D only :P

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its not D i'm answering wait.

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answered. :)

Answer 1

 

$I_2$	$I_1$	$I_0$		$O_8$	$O_7$	$O_6$	$O_5$	$O_4$	$O_3$	$O_2$	$O_1$	$O_0$
0	0	0		0	0	0	0	0	0	0	0	0
0	0	1		0	0	0	0	0	0	0	0	1
0	1	0		0	0	0	0	0	1	0	0	0
0	1	1		0	0	0	0	0	1	0	0	1
1	0	0		0	0	1	0	0	0	0	0	0
1	0	1		0	0	1	1	1	1	1	0	1
1	1	0		0	1	1	0	1	1	0	0	0
1	1	1		1	0	1	0	1	0	1	1	1

 

Cube of 7 is $343$ which requires 9 bits but this can be reduced because

$I_2 = O_6$ and

$I_0 = O_0 $

7 Bits are sufficient. So the answer is $B) \ 8 \times 7$

Comments

Omg!! such reduction!! :O _/\_

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lol :p