Got a few questions:
What should I chuck on my cheat sheet for modulation? I don't think we touched on it during the year but the exams seem to look to ask questions on it. I was thinking of just putting what an information signal/unmodulated signal/modulated signal/carrier wave looks like.
If anyone is doing structures & materials; What's the difference between strain energy and toughness? Are they both the same thing or is one multiplied by volume? Also, when reading a f-x graph do we calculate the area under the graph (similar to a stress-strain graph) for strain energy?
modulation: yeah just a diagram is fine, make sure you know the few key points they look for in worded questions like
- the reason for modulating signals for transmission
- the process, from modulating to sending to demodulating and what waves are involved (signal wave, carrier wave, modulated carrier wave, etc)
strain energy: the energy of an object under load due to its strain which is given by the area under stress-strain graph, then multiplied by volume. the area in question might not be the whole graph, all the way to failure.
toughness: the maximum strain energy density of a material, a property of the material that describes how much energy a unit of volume or that material can take to failure. because of this, it's always calculated as the full area under the stress strain graph, and because it's not object-specific, it's material specific, you don't multiply by volume.
hope that helps!