# Testing I/F Frequencies

Discussion in 'Electronic Basics' started by James Douglas, Feb 12, 2006.

1. ### James DouglasGuest

I am building a 2m/6M radio receiver and studying it's design at the
same time. I am "lost" when it comes to visualizing how the I/F stuff
is working. I have "CircuitMaker" and wanted to create a circuit which
I could simulate and see how it's working but can't find a schematic of
how to do it?

I am interested in seeing how by combining two frequencies the output is
"the sum and difference" etc, and the basic working of Intermediate
Frequency. BTW the radio is a "dual conversion" type where it takes
the input freq and converts it to 10.7Mhz then converts again to
455Khz, etc. If it matters the kit is the Elenco AR-2N6 receiver.

Thanks!

Jim Douglas

2. ### Bob MastaGuest

world and the rest of the world using "mixing" differently. The
secret is that in RF, "mixing" really means "multiplication". If
you multiply 2 sinusoids together, the product has components
only at sum and difference frequencies of the original inputs.
This is that same old trig relationship you probably already
forgot from high school for the product of sines or cosines.

sin(A) * sin(B) = 1/2 * cos(A-B) - 1/2 * cos(A+B)

As an aside, this is the same relationship behind Fourier
analysis. You migth want to check out "Gut-Level
Fourier Transforms - Everything You Need, You Got In
High School" at
www.daqarta.com/eex01.htm

Best regards,

Bob Masta