# Computer Science Essay

417 WordsOct 8, 20142 Pages
[pic] IST 4060: TELECOMMUNICATIONS AND NETWORKS ASSIGNMENT #1 [Spring 2014] Given on: 29th September 2014 Due:13th October 2014 Lecturer: Dr. G. Chege (gchege@usiu.ac.ke) _______________________________________________________________ Answer all the Questions (In all cases show your working !) 1) Commonly, medical digital radiology ultrasound studies consist of about 25 images extracted from a full-motion ultrasound examination. Each image contains a 1024 x 1024 pixels, each with 8 bits of intensity information. a) How many bits are there in the 25 images? b) Ideally, however, the doctors would like to use 1024 x 1024 x 8-bit frames at 30 frames/sec. Ignoring possible compression and overhead factors, what is the minimum channel capacity required to sustain this full-motion ultrasound? c) Suppose that each full-motion study consists of 30 sec of frames of type (b) above. How many such studies could fit on a 600-MB CD ROM? 2) According to Shannon’s information theory, the maximum data rate for a noisy signal is given by: B= H log2 (1+S/N) Where: B = data rate in bits per sec H = bandwidth S/N = Signal-to-Noise ratio. Use this equation to answer the following question: If a binary signal is sent over a 3-KHz channel whose signal-to-noise ratio is 20dB, what is the maximum achievable data rate (i.e. the channel capacity)? 3) The highest generally available data rate for modems operating on general voice grade circuits is 28.8 kbps. Some claim that this is very close to the Shannon limit. Suppose that 28.8 Kbps is the Shannon limit and assume a voice channel bandwidth of 3,300 Hz. What signal to noise ratio does this imply? 4) Suppose a file of 30,000 characters is sent over