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Recent questions tagged error-detection

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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 $\mathcal{C}$
asked Apr 8, 2019 in Digital Logic akash.dinkar12 270 views
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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.
asked Apr 6, 2019 in Digital Logic ajaysoni1924 315 views
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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
asked Mar 17, 2019 in Computer Networks Nishi Agarwal 1.5k views
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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.
asked Mar 17, 2019 in Computer Networks Nishi Agarwal 2.1k views
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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.
asked Mar 16, 2019 in Computer Networks ajaysoni1924 182 views
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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.
asked Mar 16, 2019 in Computer Networks ajaysoni1924 309 views
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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.
asked Mar 16, 2019 in Computer Networks ajaysoni1924 2.6k views
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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.
asked Mar 16, 2019 in Computer Networks ajaysoni1924 121 views
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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?
asked Mar 16, 2019 in Computer Networks ajaysoni1924 337 views
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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?
asked Feb 7, 2019 in Computer Networks superak96 378 views
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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?
asked Jan 30, 2019 in Compiler Design sreenivas.s1995 130 views
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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?
asked Jan 4, 2019 in Computer Networks vinay chauhan 495 views
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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.
asked Nov 30, 2018 in Computer Networks Gupta731 234 views
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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
asked Nov 26, 2018 in Computer Networks Ashish Goyal 364 views
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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?
asked Nov 24, 2018 in Computer Networks John Doe 187 views
2 votes
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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
asked Nov 19, 2018 in Computer Networks iarnav 984 views
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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?
asked Nov 16, 2018 in Computer Networks iarnav 178 views
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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
asked Oct 15, 2018 in Computer Networks Vegeta 167 views
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To guarantee correction of upto $t$ errors, the minimum Hamming distance $d_{min}$ in a block code must be ______ $t+1$ $t-2$ $2t-1$ $2t+1$
asked Jul 13, 2018 in Computer Networks Pooja Khatri 1.6k views
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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
asked Jun 15, 2018 in Computer Networks bts 834 views
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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?
asked May 2, 2018 in Compiler Design rahul sharma 5 242 views
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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 ?
asked Oct 18, 2017 in Computer Networks just_bhavana 1.9k views
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