help me in my project

i am a mechanical engg. student. I need help in my project.

i need a circuit which can do following work
1. detect amplitude from a given source
2. i have a graph of amplitude verses one another quantity( say x factor) used in my project...
i need the device to detect the amplitude from the input device and then observing the graph displays the value of that another quantity(x factor) on a monitor and beep a sound when it goes out of a range....

pleaze help because I am a mechanical engg. and dont have much idea about it... give me suggestions, idea, cost & other details...etc...

Your warning circuit probably requires a "window comparator." The rest of your project details are not specific enough to provide a solution for.

Example Window Comparator Circuit

reply to brown

Thanks for the reply Brown,

I am again explaining my project.
Infact , there is a system which produces (after various processes and modulations) a wave. The frequency of the wave is already known. I think the amplitude of the wave can be measured by any device. Suggest if you have any good suggestion about that. Now we have a known plot of graph between amplitude and one another quantity (x factor). we have to construct a device in which the graph can be input and then by using the graph the x factor can be known and can be displayed over the display unit. please give me every detail because i have a very little idea of electronics