421 CS Homework II Fall 2003
Dated : 30 September 2003 Due on : 3 October 2003 Total Points : 50
Note about Submission: Computer-typed document is preferrable. If you plan to submit handwritten, please write legibly and clearly. Submit by 6 p.m on 3rd October in Room 451, Flarsheim hall
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(a) Calculate the bit overhead and time overhead if we were to use Asynchronous transmission. Assume every character is encoded using 8-bits (1 byte) with a 1 start bit and 2 stop bits. (b) Calculate the bit overhead and time overhead if we were to use Synchronous transmission. Assume the synchronous frame consists of 800 characters (6400 bits) along with 50 bits of control information.
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Suppose considered in the previous problem is transmitted in a channel which is erroris found out to be . Thus is not error-free. Use the circuit from the prone and previous problem to nd out whether error in can be detected. If it cannot be detected, explain why.
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Draw the shift register circuit. For , compute using the circuit. Perform the division to verify your result. Form from and as follows: . Pass circuit in (a) and verify that the contents of shift registers are zero at the last step.
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6. Assume , the message polynomial with a maximum degree of 9 and the polynomial is .
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Assume the message be to transmitted is 1001001110101101100101001101. Divide this message into rows of 7 bits each. Using two-dimensional even parity scheme, generate the parity bits along the row and the columns. , the generator
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An asynchronous transmission scheme uses 7 data bits, 1 start bit and 1 stop bit. If and represents the clocking period of sender and receiver respectively, derive the bounds of in terms of such that the sender and the receiver can still be synchronized.
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Assume 1 Kbits = 1000 bits; 1 Mbyte = 1000 Kbyte = 8000 Kbits
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Suppose a le of size 2 Mbytes is to be transmitted over a line of 56 Kbps. Determine the following:
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How many states are required with Quadrature Amplitude Modulation (QAM) scheme if each signal element represents three bits. Give those signal elements. Hint: Use combination of amplitude and phase. You can assume arbitrary amplitudes .
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Plot the bandwidth efciency (
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(a) What is the maximum number of guaranteed correctable errors? (b) What is the maximum number of errors that can be detected, not neccessarily corrected?
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Calculate the minimum hamming distance of the following code: 00000, 10010, 10011, 11000, 00110, 00111, 11011, 01011. Answer the following:
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Calculate the hamming pairwise distances between the following codes: 0000001, 10010110, 10110010, 11101101 Hint: Take two codes at a time