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TASK – DECODER TASK DESCRIPTION A decoder is a device that has n inputs and 2n
outputs. Each combination of inputs
leads to exactly one output being set to 1 and all others being set to 0.
Above, you see a block diagram of a 2 x 4 decoder which is simply a
decoder with 2 inputs and 4 outputs.. You will learn how and encoder works and create one in this task. THEORY As mentioned above, a decoder has n
inputs and 2n outputs. Each
output will be 1 only for a specific input combination. The idea is that the decoder decodes the
binary value of the inputs and sets that one corresponding output to 1 and
all other outputs to 0. A 1-input decoder, also known as a 1
x 2 decoder, has the following truth table: A
D0 D1 0 1
0 1 0
1 A 2-input decoder, also known as a 2
x 4 decoder, has the following truth table: A
B D0 D1
D2 D3 0 0
1 0 0
0 0
1
0 1
0 0 1
0 0
0 1 0 1 1
0 0 0
1 Notice that the binary value of the
inputs A and B corresponds to the number of the D output that is set to 1. For example, when AB are 11, which is 3 in
decimal, it is D3 that is set to 1. The circuit for a 2x4 decoder looks
like this:
TASK Create a 2x4 decoder to
earn a max of 90%. You must connect the
outputs to lightbulbs to see which line is on. You must label your
inputs and outputs with A, B, D0, D1, … Your outputs need to be
placed in order. TO SUBMIT A screen capture of you decoder. Try researching different uses for a
binary decoder. |
