# Homework 4

## Due date and weights

This is a 30-point assignment due on Monday
14 March, 2011. You may turn your solution in at class
or submit via moodle.

In this homework you will illustrate some of the coding techniques described
in the
coding binary bits lecture.
For the first problem it will probably be easiest to draw your
answer on lined paper.

## Problem 1

Draw the encodings (binary levels) of sending the following seven-bit
sequence `0110101`

using the following four encoding schemes.

- NRZ
- RZ
- Manchester
- Differential Manchester

## Problem 2

Suppose the 32-bit sequence
`00111111 00001111 11110000 00111111`

is to be transmitted though a communications channel using
bit stuffing after 6 bits of 1's.
Write the bit sequence that will actually be tranmitted using
this encoding scheme.

## Problem 3

Suppose the 32-bit sequence
`00111111 00001111 11110000 00111111`

is to be transmitted though a communications channel using
8b/10b.
Write the bit sequence that will actually be tranmitted using
this encoding scheme.

## Problem 4

Suppose the first three letters of your last name are going to
get transmitted through a RS232 channel at 9600 baud using
7 data bits, even parity, and 1.5 stop bits. Draw
the voltage levels used in this trasmission.
Be sure to indicidate the length (in time) of at least one of the bits.