# Recent questions tagged error-detection 1 vote
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1
If the original size of data is $40$ then after adding error detection redundancy bit the size of data length is $26$ $36$ $46$ $56$
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Consider a simple code $\mathcal{C}$ for error detection and correction. Each codeword in $\mathcal{C}$ consists of $2$ data bits $[d_1, d_0]$ followed by check bits $[c_2, c_1, c_0]$ ... $2$ addition. Write down all the codewords for $\mathcal{C}$ Determine the minimum Hamming distance between any two distinct codewords of $\mathcal{C}$
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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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4
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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23: We need a dataword of at least 11 bits. Find the values of k and n in the Hamming code C(n, k) with dmin :3. Soln: We need to find k = 2m −1 − m ≥ 11. We use trial and error to find the right answer: a. Let m = 1 k = 2m −1 − m = 21 −1 − 1 = 0 (not acceptable) b ... = 4 k = 2m −1 − m = 24 −1 − 4 = 11 (acceptable) Comment: The code is C(15, 11) with dmin = 3. How this n=15 came?? please explain
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32: A sender needs to send the four data items Ox3456, OxABCC, Ox02BC, and OxEEEE. Answer the following: a. Find the checksum at the sender site. b. Find the checksum at the receiver site if there is no error.
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The goal of this lab exercise is to implement an error-detection mechanism using the standard CRC algorithm described in the text. Write two programs, generator and verifier. The generator program reads from standard input a line of ASCII text containing an n-bit message ... see that the message is correct, but by typing generator <file | alter arg | verifier you should get the error message.
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A 1024-bit message is sent that contains 992 data bits and 32 CRC bits. CRC is computed using the IEEE 802 standardized, 32-degree CRC polynomial. For each of the following, explain whether the errors during message transmission will be detected by the receiver: (a) There was a ... were 47 isolated bit errors. (e) There was a 24-bit long burst error. (f) There was a 35-bit long burst error.
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A bit stream 10011101 is transmitted using the standard CRC method described in the text. The generator polynomial is x 3 + 1. Show the actual bit string transmitted. Suppose that the third bit from the left is inverted during transmission. Show that this error is detected at the receiver’s end. Give an example of bit errors in the bit string transmitted that will not be detected by the receiver.
1 vote
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10
What is the remainder obtained by dividing $x^7 + x ^5 + 1$ by the generator polynomial $x^ 3 + 1?$
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11
Suppose that a message 1001 1100 1010 0011 is transmitted using Internet Checksum (4-bit word). What is the value of the checksum?
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12
A block of bits with n rows and k columns uses horizontal and vertical parity bits for error detection. Suppose that exactly 4 bits are inverted due to transmission errors. Derive an expression for the probability that the error will be undetected.
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13
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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14
To provide more reliability than a single parity bit can give, an error-detecting coding scheme uses one parity bit for checking all the odd-numbered bits and a second parity bit for all the even-numbered bits. What is the Hamming distance of this code?
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15
Give two reasons why networks might use an error-correcting code instead of error detection and retransmission.
2 votes
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16
For detecting a single bit error using CRC, it is needed that $x^{i}$ should not be divisible by g(x). So, we make g(x) of at least 2 terms, which renders a single term of e(x) indivisible. But then what is the logic behind keeping MSB as 1. Isn't just keeping ... to make any single bit indivisible? For example, $x^{3}+x^{2}$ is guarantees to detect a single bit error at any position. Is it not?
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17
Which phase of the compiler detects the error? #include<stdio.h> int main() { printf(“%d”,2..3); return 0; } I think lexical analyzer am i correct?
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18
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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19
TCP UDP IGMP ICMP I think ICMP can’t correct the error in data and rest three protocols can correct data errors!
1 vote
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20
Which of the following statements is FALSE for the generator $x^{6}$+1? S1: This generator can detect all burst errors with a length of 5 bits. S2: This generator can detect some but not all burst errors with a length of 6 bits.
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21
Data transmitted on a link uses the following 2D parity scheme for error detection: Each sequence of 28 bits is arranged in a 4 7 matrix (rows r0 through r3, and columns d7 through d1) and is padded with a column d0 and row r4 of parity bits computed using the Even ... link. The table shows data received by a receiver and has n corrupted bits. What is the mini­mum possible value of n? 1 2 3 4
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22
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?
2 votes
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23
If the Hamming distance between a dataword and the corresponding codeword is three, there are _____ bits in error. A) 5 B) 4 C) 3 D) none of the above
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24
How many bit errors can simple parity bit error detection or 1-D parity bit can detect? I'm pretty confused about it - that can I detect only one bit errors or all odd bit errors can be detected?
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25
CRC can detect any odd number of errors. CRC can detect all burst errors of less than the degree of the polynomial. Please explain and if possible give proof
1 vote
2 answers
26
To guarantee correction of upto $t$ errors, the minimum Hamming distance $d_{min}$ in a block code must be ______ $t+1$ $t-2$ $2t-1$ $2t+1$
1 vote
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27
Let C be a binary linear code with minimum distance 2t + 1 then it can correct upto _____ bits of error. A t + 1 B t C t - 2 D t / 2
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28
Consider the following set of codewords(Last bit is even parity of the first two bits) 000 011 101 110 Now here min. hamming distance is 2 and if i apply formulae Min. hamming distance =d+1,then d errors can be detected 2=d+1 d=1 Means 1 error can be detected. But ... become odd. So 3 bit error can also be detected,but by formula it says 1 bit error can be detected. Please tell what did i miss?
1 vote
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2 votes
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30
To provide more reliability than the Single Parity Bit technique, a new error-detecting scheme has been proposed. The scheme uses first parity bit for checking all the odd numbered bits and a second parity bit for all the even numbered bits. What is the (minimum) Hamming distance of this code ?