Devise a 7-bit even-parity Hamming code for digit 7. (just digit 7, no more, no less please)

[Enrique Padilla]

I understand Hamming code, but the way the question is formulted im not sure what is being asked? 

A 7 bit hamming code for digit 7? 

so it would want two options ?

1000000|1 == 1 (true)

0000000|0 == False 

having the even bit on the 8th or 7th digit? 

[joseph lee]

I had confusion on this also. I was assuming we place the parity on the 7th so we would make 1000111.

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[Enrique Padilla]

So its 7 bits long, and just put a 1 or 0 on the 7th bit depending what bits you have ?

Ergo :

if i have 0010101

that has 3 bits and since its even it would be converted to:

1010101

[Frank (sjsu) Lin]

Let's not confuse Hamming code and Hamming distance.  As far as I know, Frank specifically said that we're not dealing with Hamming code.  Am I mistaken?

Of course, if you prefer to have it in the exam, I can accommodate.

[joseph lee]

Actually no wait,  I think you got it right on the first post. My bad. It would be 1|0000111.

[Laimonas Turauskas]

To represent digit 7 we can use 4 bits, like 0111. Then we have parity bits which will be at positions 1 2 and 4. Each parity bit is responsible to keep track of other bits. For example 

1 is responsible for 1,3, 5, 7, ...

2 is responsible for 2,3,6,7, ...

4 is responsible for 4,5,6,7, ...

so 7 bits to represent digit 7 would be xx0x111,

where x is represented by parity bit. Since, parity bit has to be an even number when summed up with 

bits responsible, you can determine the bit.

So 1 would be, bit1 + bit3 + bit5 + bit7 = even number. So,

x + 0 + 1 + 1 = x + 2 = 0 + 2

As you can see bit1 is 0 because that way it makes the sum even.

You can do this for rest of parity bits and will get

0001111 to represent digit 7. 

For more information check page 80 of the textbook 6th edition.  Specially the part with Venn Diagrams.

[Lance Barrett]

I'm pointedly not going to reply to any of the responses in this thread, except to say that I'm taking Prof. Frank at his word and omitting study of Hamming Distance for the Mid-Term as I have a slew of other more important topics that have been confirmed WILL be on the exam.

[Marvin Ramos]

Actually, he said not to confuse Hamming Code with Hamming distance. We did go over Hamming distance, but not Hamming code.

[Frank (sjsu) Lin]

Thanks Marvin.

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[Lance Barrett]

Ah yes, Hamming code.... mis-typed.

[Aymeric Botella]

So that means that number 6 wouldn't be anything we covered and wouldn't be on the exam yeah?

On Tue, Mar 5, 2013 at 11:21 PM, Lance Barrett <lanc...@gmail.com> wrote:

Ah yes, Hamming code.... mis-typed.

[Marvin Ramos]

Yes, Frank lin said it wouldnt be on the test a few posts ago