Test by Bikram | Digital Logic | Test 2 | Question: 27

Question

Which among the following statements is TRUE?

• A. A circuit containing only OR and NOT gates must be a combinational circuit.
• B. SRAM is “static” in the sense that if the power is turned off, SRAM will continue to store data (e.g. as in flash memory in MP3 players or USB thumb drives).
• C. In the two’s complement number representation, a negative number with more leading ones is larger (i.e. less negative) than a negative number with fewer leading ones.
• D. For numbers represented in two's complement form, the negative of a number can be found by adding one and then inverting the bits.

Comments

Thanks a lot sir for clearing the concept.

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Sir ,

but why wont sign extension condition apply here ?

1111 1110 and 1110 are the same.

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@Harsh181996 2's complement representation would dictate the number of fixed mandatory bits to be used. You can't arbitrarily perform sign extension if you have a fixed format, which is the case here.

Answer 1

hey bikram

In the two’s complement number representation, a negative number with more leading ones is larger (i.e. less negative) than a negative number with fewer leading ones.

It is like ambigous statmnt make it more clear.

Comments

take an example for option C

−42  in 8 bit   1101 0110

−128 in 8 bit

1000 0000

here 42 is less negative than 128 .

Reference

 https://en.wikipedia.org/wiki/Two's_complement#Example

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@bikram sir, the nos can be equal also in some cases, right? For example, 1110 is same as 110 in 2's complement repreentation, isn't it?

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@Shraddha No. For a given representation we have to assume a "fixed" no. of bits. Also, 2's complement and 2's complement representation are not the same.

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ok. Thank you sir.