# Modulation and signals

1. Jan 28, 2006

### dervast

Hi do u have any good articles about signals and modulation...
I want to know why we use modulation and how the world would be if no modulation was used at all...
Waht arre the types of modulation?
What are the differences between them?

2. Jan 29, 2006

### Maxwell

This sort of sounds like homework.

Amplitude Modulation (AM), Frequency Modulation (FM), and Phase Modulation (PM) are a few types of modulation. Look these up on the internet (use google) and you'll find the answers you need.

3. Jan 29, 2006

### Staff: Mentor

Yep, google is a great tool. I googled modulation communication theory, and got lots of good hits. This one from wikipedia was one of the first ones, and looks pretty helpful:

http://en.wikipedia.org/wiki/Modulation

4. Jan 29, 2006

### Averagesupernova

Yeah this sounds an awful lot like homework but let me just ask you if a signal is not modulated in any way, in other words it simply exists as a steady state, what information is it conveying? Does that give you an idea of what the world would be like with nothing modulated?

5. Jan 29, 2006

### Ouabache

The signal would convey no communication information except the amplitude and frequency of the carrier signal, which is typically a radio frequency (RF), but could be any sinusoidal wave in the electromagnetic spectrum.

6. Jan 29, 2006

### Averagesupernova

It was a rhetorical question meant for the OP. I already knew the answer.

7. Feb 11, 2006

### dervast

Ok thx but we can use the signals ups and down to represent 1 and 0 accordingly....
If we modulate a signal what kind of information it conveys

8. Feb 11, 2006

### Averagesupernova

What you just described IS modulating the signal.