04-20-2014 01:57 PM
I'm trying to simulate DSB AM in multisim with VBM voltage source
so I have
Vu=Vm*Vc
I can't seem to get the Fourier Analysis to display correctly. The graph only display up to four times the fundalmental frequency . My carrier is at 1Mhz and my message is at 10Khz all sine waves. So ideally, I should get three peaks: 0.99Mhz, 1Mhz and 1.01Mhz.
Is it possible to use configure the fourier analysis so that I can see these peaks?
Please help.
See attached for schematic.
04-21-2014 10:53 AM
Anyone???
04-29-2014 01:35 PM
Hi,
I am using the Network Analyzer to simulate your circuit the result shows two bands, one at 990 kHz and another 1.01MHz. From the following trigonometric indentities: sin(x)*sin(y) = 1/2 {cos(x-y) -cos(x+y)}, and it looks like the Multisim simulation is correct it.
I looked up AM modulation from the following page:
http://www.pa2old.nl/files/am_fundamentals.pdf
It looks like the express is:
There is an AM source avalable in the Multisim database, it's located in "Sources" group under the "Signal Voltage source".