How do you convert hex numbers from 12bit to 18bit keeping twos complement.?

Question

the two examples i have are

253h

c75h

do i need to convert to binary first?

any help would be appreciated

Answer 1

You need a hexidecimal conversion tool...

Answer 2

253  is a positive # so you just add 0s in front.

C75  is negative so you need to keep the high order 1 BIT, and add 0s after it.

one might note that hex representation is good for 4, 8, 12, 16, 20, 24, etc bit numbers.   18 is unusual, to say the least.  the high order digit could only be 0,1,2, or 3.

C75 in 18 bit would be 10475.  yw

Answer 3

Get a calculator with bases on it.

try this

http://www.convertit.com/Go/ConvertIt/Ca...

You haven't said how many bits you are using.