Design a 2 to 4 Decoder using 4 to 16 Decoder

[Fatima Hasan]

Homework Statement

How to design a 2 to 4 Decoder using 4 to 16 Decoder ?

Homework Equations

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The Attempt at a Solution

Truth Table :
A B
0 0
0 1
1 0
1 1 ( O3)
Is my answer correct ?

 

[scottdave]

Do you have the datasheet for this device? Is A the high bit, or low bit? The way you show your truth table, it looks like A is the High bit.
Where do you want to read the 4 outputs? From Q(0) through Q(3)?

My initial observation is: your truth table is incorrect, because it only show inputs (A and B). You do not show what outputs are associated with these states.

 

[Fatima Hasan]

A B - OP
0 0 - O0
0 1 - O1
1 0 - O2
1 1 - O3

 

[Fatima Hasan]

Do you have the datasheet for this device?

No.

From Q(0) through Q(3)?

Yes.

 

[scottdave]

There are several manufactured 4 to 16 decoders, like this one for example http://www.ti.com/lit/ds/symlink/cd74hc4515.pdf
Note the inputs on that one (and several that I searched) are labeled A0 (least significant) to A3 (most significant bit). This leads me to "guess" that A in yours is least significant, then B, then ( C & D , which are grounded so they are fixed to zero). How would a truth table look like in that situation?