If ASCII "A" and "a" are combined into a 16-bit pattern and then appended with a FCS (Frame Check Sequence) generated by a CRC polynomial of $X^5 + X^4 + X + 1$. Determine the FCS. A is 41H and a is 61H in ASCII Show how to verify if the data is corrected or not.
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41H = 0100 0001 61H = 0110 0001 Combine them into a 16-bit pattern: 0100000101100001 Show more…
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Give short answers to the following questions. Answer Q1-Q4 by using the following information. A data frame contains a text of 8 characters "ethernet" encoded using ASCII characters. NOTE: the required ASCII values are: e = 1100101 t = 1110100 h = 1101000 r = 1110010 n = 1101110 Assuming this, determine: Q1. Codewords for the text "ethernet" using even parity. Q2. Two-dimensional parity check bits for the text "ethernet" using even parity. Q3. Codeword at the sender site for the dataword "h" using the divisor x^4 + x^2 + x + 1. Q4. Checksum at the sender site for the text "ethernet". Hint: Use hexadecimal equivalents of the characters. e = 0x65 t = 0x74 h = 0x68 r = 0x72 n = 0x6E Q5. Show the checking of codeword 10010001101 at the receiver site by using the divisor x^4 + x^2 + x + 1. Is there an error? Q6. Find the checksum at the receiver site if the four data items are received as 0x6674, 0x7865, 0x726F, 0x5584, 0x5A43. Is there an error? Q7. Find the codeword at the sender site for dataword 1110 using Hamming code C(7,4). Q8. The codeword 1100010 is received. Using the Hamming code C(7,4), find if there is an error in the codeword. If there is, what is the correct codeword and dataword sent?
Akash M.
Consider a CRC error detection scheme with a generator polynomial G (x) = x^4 + x + 1. We want to encode the bits 10010011011 at the sender using the CRC, and then transmit the encoded bit sequence over a link to the receiver. Suppose the link introduces an error pattern 100010000000000, i.e. a flip from 1 to 0 or from 0 to 1 in positions 1 and 5. The receiver will apply CRC error detection on the received bit sequence in order to detect the errors. (a) What is the bit sequence that is transmitted by the sender to the link? (b) What is the bit sequence that is received by the receiver? (c) Can the error be detected by the receiver? Why? (d) Repeat (b) and (c) with the error pattern 100110000000000.
Q3-) [30pt] a-) (15pt) Calculate the parity bits for 16-bits data with a value of 0xACDC. 0xACDC => 1010 1100 1101 1100 b-) (15pt) Consider a SEC code that protects 8-bit words with 4 parity bits. If we read the value 0xABC, is there an error? If so, correct the error. Note: 0xABC = 1010 1011 1100 Hint: Decode the 12-bit encoded data and find if there is an error.
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