# Recent questions tagged error-correction 1
Which of the following is minimum error code? Octal Code Binary Code Gray Code Excess-$3$ Code
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It is necessary to formulate the hamming code for four data bits $D _3, D _5, D _6 and D _7$ together with three parity bits $P _1, P _2 and P _3$ ... to include the double bit error detection in the code. Assume that error occurs in the bit $D _5 and P _2$. Show how the error is detected.
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How many parity check bits must be included with the data word to achieve single-bit error correction and double error correction when data words are as follows: 16 bits 32 bits 48 bits
1 vote
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A 12-bit hamming code word 8-bits of data and 4 parity bits are read from the memory. What was the original 8-bit data word that was written into the memory if the 12-bits word read out are as follows: 000011101010 101110000110 101111110100
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Given the 8-bit data word 01011011, generate the 13-bit composite word for the Hamming code that corrects the single bit error and detects double bit errors.
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Give two reasons why networks might use an error-correcting code instead of error detection and retransmission.
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How many bits can a 2-dimensional parity detect and correct? Is there any general formula for no of bit detection and correction for N-dimensional parity?
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TCP UDP IGMP ICMP I think ICMP can’t correct the error in data and rest three protocols can correct data errors!
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The IP protocol implements Internet checksum over just the IP header. As the packet passes through the routers, one field called Time To Live (TTL) (8-bits long) in the IP header is decremented at each router. So, each router needs to decrement this field ... update the checksum in the header. Is there a way to update the checksum without having to recalculate the checksum over the entire header?
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To guarantee correction of upto $t$ errors, the minimum Hamming distance $d_{min}$ in a block code must be ______ $t+1$ $t-2$ $2t-1$ $2t+1$
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Minimum Number of bits required to correct single bit error.
1 vote
12
Can someone plz explain this highlighted text ? I took it from Tannenbaum. thank you :)
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Assume x, y and z are n bit binary numbers then which of the following inequalities hold about Hamming Distance between them? A. HD(x,y)+HD(y,z)>=HD(x,z) B. HD(x,y)+HD(y,z)<=HD(x,z) C. HD(x,y) - HD(y,z)>=HD(x,z) D. None of the above
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A 12-bit Hamming code whose hexadecimal value is 0xE4F arrives at a receiver. What was the original value in hexadecimal? Assume that not more than 1 bit is in error.
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Start and stop bits are used in serial communications for Error detection Error correction Synchronization Slowing down the communication
1 vote
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If the data unit is 111111 and the divisor is 1010. In CRC method, what is the dividend at the transmission before division? 1111110000 1111111010 111111000 111111
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The hamming distance between the octets of $\text{0xAA}$ and $\text{0x55}$ is 7 5 8 6
With $1$ parity bit we can detect all $1$-bit errors. Show that at least one generalization fails, as follows: (b) Find an $N$ (not necessarily minimal) such that no $32$-bit error detection code applied to $N$-bit blocks can detect all errors altering up to $8$ bits.
With $1$ parity bit we can detect all 1-bit errors. Show that at least one generalization fails, as follows: (a) Show that if messages $m$ are $8$ bits long, then there is no error detection code $e = e(m)$ of size $2$ bits that can detect all $2$-bit errors. Hint: Consider ... with a $2$-bit error, and show that some pair of messages $m_{1}$ and $m_{2}$ in $M$ must have the same error code $e$.
Show that two-dimensional parity provides the receiver enough information to correct any $1$-bit error (assuming the receiver knows only $1$ bit is bad), but not any $2$-bit error.