Modulation Question

[Andiio]

Just quickly went through it in class today, but a bit hazy with a few ideas so I'd love a bit of clarification if possible!

1. Does the transducer (e.g. a microphone) supply the information wave?
2. What supplies the carrier wave? (or is it just light etc)
3. How come suitable modulators include LED whereas suitable demodulators include LDR & photodiodes?

Thanks!

[Shark 774]

Just quickly went through it in class today, but a bit hazy with a few ideas so I'd love a bit of clarification if possible!

1. Does the transducer (e.g. a microphone) supply the information wave?
2. What supplies the carrier wave? (or is it just light etc)
3. How come suitable modulators include LED whereas suitable demodulators include LDR & photodiodes?

Thanks!

Yes a microphone for example will give an information wave. The carrier wave will be the light from an LED or Laser Diode. This will be at a constant light intensity (a straight horizontal line on a light intensity vs time graph) or a constant amplitude (a sine wave with constant period and amplitude on an amplitude vs time graph) when there is no input signal. When a signal is input the light intensity or amplitude will vary accordingly to "carry" the shape of the input signal. Basically, for an example of a simple photonics systems: a microphone produces an electrical signal and as this signal varies the signal emitted from an LED or Laser Diode (these devices turn electrical signals into light signals) also varies accordingly. This light signal from the LED or Laser Diode is then picked by a photodiode or LDR (these devices turn light signals into electrical signals) and then we can get the shape of the wave we started with.

I hope this answers your questions?

[Lols123]

do we have to know much about modulation for the course? or is it mainly for further electronics?

[Vincezor]

do we have to know much about modulation for the course? or is it mainly for further electronics?

I don't believe there is any modulation in further electronics.

I can see the examiners putting in atleast one question relating to modulation. Probably a good idea to do some exams and see the sort of questions related to modulation. The theory questions may be asked, and I personally am horrible when it comes to theory :S

[Andiio]

do we have to know much about modulation for the course? or is it mainly for further electronics?

I don't believe there is any modulation in further electronics.

I can see the examiners putting in atleast one question relating to modulation. Probably a good idea to do some exams and see the sort of questions related to modulation. The theory questions may be asked, and I personally am horrible when it comes to theory :S

That's where the cheat sheet comes in! Anyone started on making it yet? If I recall it is double-sided, right?

[Vincezor]

That's where the cheat sheet comes in! Anyone started on making it yet? If I recall it is double-sided, right?

Funny that, I opened up a new word document earlier today and typed some formulas for motion down. I have a motion SAC next week so I'll be aiming to get atleast the motion stuff down so I can use that part for my SAC . I honestly don't feel like I need to put much for AOS2, maybe I'll just put all the modulation theory down.

[Shark 774]

That's where the cheat sheet comes in! Anyone started on making it yet? If I recall it is double-sided, right?

Funny that, I opened up a new word document earlier today and typed some formulas for motion down. I have a motion SAC next week so I'll be aiming to get atleast the motion stuff down so I can use that part for my SAC . I honestly don't feel like I need to put much for AOS2, maybe I'll just put all the modulation theory down.

What do you mean by modulation theory?

[Vincezor]

That's where the cheat sheet comes in! Anyone started on making it yet? If I recall it is double-sided, right?

Funny that, I opened up a new word document earlier today and typed some formulas for motion down. I have a motion SAC next week so I'll be aiming to get atleast the motion stuff down so I can use that part for my SAC . I honestly don't feel like I need to put much for AOS2, maybe I'll just put all the modulation theory down.

What do you mean by modulation theory?

Well, all of the modulation stuff is pretty much theory. Guess I'll just put definitions or something like I wrote above. Maybe I'll include a simple diagram of the whole thing as well.

[Shark 774]

That's where the cheat sheet comes in! Anyone started on making it yet? If I recall it is double-sided, right?

Funny that, I opened up a new word document earlier today and typed some formulas for motion down. I have a motion SAC next week so I'll be aiming to get atleast the motion stuff down so I can use that part for my SAC . I honestly don't feel like I need to put much for AOS2, maybe I'll just put all the modulation theory down.

What do you mean by modulation theory?

Well, all of the modulation stuff is pretty much theory. Guess I'll just put definitions or something like I wrote above. Maybe I'll include a simple diagram of the whole thing as well.

Right. The one thing I really don't get is drawing the modulated signal if given the carrier and input, or finding the input from the modulated signal. Got any tips?