You are Here: Home >< Physics

# Amplitude modulation graph sketching help need watch

1. question:
Draw an amplitude modulated wave with a carrier wave frequency 1.0MHz and a signal frequency of 100kHz. The time axis on your graph should be from 0 to 10 mili seconds. On your graph mark time for one complete wave of signal and for one complete wave of carrier.

How would i draw this graph? the time period for Carrier i calculated is 10^-6 and signal its 10^-5 seconds
but the amplitude modulated wave would have which time period? and will it look like/.
2. Draw your carrier wave then using the period you calculated for it.

Then inside that 'envelope' draw another wave 10 times the frequency, ie with the period you calculated for the carrier.

It'll look something like this but made to fit your frequencies. https://www.tutorialspoint.com/analo...lated_wave.jpg
3. (Original post by phys981)
Draw your carrier wave then using the period you calculated for it.

Then inside that 'envelope' draw another wave 10 times the frequency, ie with the period you calculated for the carrier.

It'll look something like this but made to fit your frequencies. https://www.tutorialspoint.com/analo...lated_wave.jpg
So if we consider a graph from 0 to 10mili seconds the carrier wave would just be a cosx graph and then ill just have to put 10 more waves inside it?
4. TBH I don't think it matters whether you make it sin or cos, but yes, one full period (which will mean two 'bumps') and 10 little waves inside it.
5. (Original post by phys981)
TBH I don't think it matters whether you make it sin or cos, but yes, one full period (which will mean two 'bumps' and 10 little waves inside it.
Thank you, one last question. Is it 10 little waves because the time period of the signal is 10 times greater than the time period of carrier.
6. yes, so if I'm picturing this correctly you'll have 5 FULL little waves in each of the 'bumps'

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: February 17, 2018
The home of Results and Clearing

### 1,062

people online now

### 1,567,000

students helped last year
Today on TSR

### University open days

1. Sheffield Hallam University
Tue, 21 Aug '18
2. Bournemouth University
Wed, 22 Aug '18
3. University of Buckingham