Homework #1 ECES 490 Telecommunications Networking

  1. Consider slide 15 in the lecture 2-3 file, titled “character-mapped images”. This is the slide that shows two versions of the same information on the left and right sides of the slide. Consider the slide as a collection of information objects (text, clip art, overall layout of the slide). For the sake of this problem, pretend that the clip art in the slide is a clip art image from a widely available clip art collection called “Joe’s Cheap Clip Art”, and corresponds to image #JCCA29718.

Create a concise text-only message that could be communicated to a remote location, which would enable the recipient of that message to create a reproduction of the slide that is good enough for most purposes you can imagine.

If it takes 1 byte of data to represent 1 text letter or one space, how many bytes of information are required to communicate the above text-only message

Now assume that the entire slide must be treated as a single bit-mapped image. Assume that the image will be represented by 1024 x 768 pixels (picture elements). Each pixel must be represented by three (3) color-intensity values (red, green, and blue). Each color intensity value for each pixel must be recorded and communicated as being one of 65,536 possible values.

How many bytes are required to represent each color intensity value for each pixel? How many bytes are required to represent the entire slide? [Remember: 1 byte= 8 bits]

What is the ratio of the number of bytes required to represent the slide as a 1024 x 768 pixel bit mapped image vs. the number of bytes required to represent the slide as a set of character mapped information objects in the first example?

For each of the two cases, above, how long would it take communicate this file from your p.c. to a friend’s p.c., using modems (at each end) that operate at 28.8 kbps. [Remember: 1 byte= 8 bits]

  1. Speech in often represented by a stream of bits at a rate of 64 kbps. How many bits are required to represent 1 second of speech? How many bits are required to represent an average 3-minute telephone conversation (assume only 1 person is talking at a time). How does this compare to the number of bits required to represent the slide in problem 1., above, in bit-mapped format (Remember: 1 byte = 8 bits).