CSCI 170 (GOLDWEBER)
Spring 08: 2/21/08
Homework 4
Playing with Circuits
Due Date: Thursday February 28, 2008.
There is a possible 24 points for this homework.
Problem 1. (8 pts.) Draw a circuit using the "sum-of-products" algorithm whose output matches the following truth table:
| a | b | c | out1 | out2 | out3 |
|
| 0 | 0 | 0 | 0 | 0 | 0 |
| 0 | 0 | 1 | 1 | 1 | 1 |
| 0 | 1 | 0 | 1 | 1 | 0 |
| 0 | 1 | 1 | 1 | 0 | 1 |
| 1 | 0 | 0 | 1 | 0 | 0 |
| 1 | 0 | 1 | 0 | 1 | 1 |
| 1 | 1 | 0 | 0 | 1 | 0 |
| 1 | 1 | 1 | 0 | 0 | 1 |
Problem 2. (10 pts. Even-parity circuit) Design an even-parity circuit. This is a circuit that has three inputs and one output. The circuit outputs a 1 if and only if an odd number (i.e. 1 or 3) of the inputs are a 1. Otherwise, the circuit outputs a 0. Thus the sum of the number of 1 bits in the input and output (i.e. that in each row the truth table) is always an even number. Provide a truth table in addition to your circuit.
Problem 3. (6 pts. Completeness) Using only AND and NOT gates provide a circuit that implements an OR circuit; a circuit with two inputs which outputs 0 if both inputs are 0, otherwise it outputs a 1.
Problem 4. (5 pts. Extra Credit) Implement an AND, OR and NOT circuit using either only nand gates or nor gates.
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On 22 Feb 2008, 14:48.