limiting amplifier using IP3 and tanh

Generate a function to represent limiting, using IP3 to specify the operation

This file shows how to specify a limiting function with IP3. The limiting is done using tanh. The file also checks out the operation of the function and compares it to the specified IP3. It shows a technique that can be used by other limiting functions so they can use IP3 to specify their operation. There are copious notes to help understanding the steps.