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# asn5-solution - Solutions to Chapter 3 1 Suppose the size...

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Solutions to Chapter 3 1. Suppose the size of an uncompressed text file is 1 megabyte. Solutions follow questions: a. How long does it take to download the file over a 32 kilobit/second modem? T 32k = 8 (1024) (1024) / 32000 = 262.144 seconds b. How long does it take to take to download the file over a 1 megabit/second modem? T 1M = 8 (1024) (1024) bits / 1x10 6 bits/sec = 8.38 seconds c. Suppose data compression is applied to the text file. How much do the transmission times in parts (a) and (b) change? If we assume a maximum compression ratio of 1:6, then we have the following times for the 32 kilobit and 1 megabit lines respectively: T 32k = 8 (1024) (1024) / (32000 x 6) = 43.69 sec T 1M = 8 (1024) (1024) / (1x10 6 x 6) = 1.4 sec 2. A scanner has a resolution of 600 x 600 pixels/square inch. How many bits are produced by an 8-inch x 10-inch image if scanning uses 8 bits/pixel? 24 bits/pixel? [3 marks – 1 mark for pixels per picture, 1 marks each representation] Solution: The number of pixels is 600x600x8x10 = 28.8x10 6 pixels per picture. With 8 bits/pixel representation, we have: 28.8x10 6 x 8 = 230.4 Mbits per picture. With 24 bits/pixel representation, we have:

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asn5-solution - Solutions to Chapter 3 1 Suppose the size...

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