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Electronics => Beginners => Topic started by: stevie3d on March 25, 2017, 08:26:00 am

Title: Connecting RF function gen to AF generator
Post by: stevie3d on March 25, 2017, 08:26:00 am
I've got a BK Precision 4040A 20 MHz Sweep Function Generator I'm trying to get a 3 to 4mhz square wave RF carrier with a 500hz through 130khz AF modulated piggybacked signal on it with a 1 to 2 sec.sweep. I have an Separate AF gen if needed. Can I just hook the outputs in parallel, or do I need matching circuits, transformer, caps, coils, resistors. I also have a function gen. amplifier 40db. and an Audio amplifier for the AF generator. I'm just trying to not smoke my $1000 worth of equipment I just bought new to a crisp. I dropped out of electronics as we were getting into RF, carriers, the stuff I need now. Thanks for any help or literature you could point me to.  Steven Dixon   
Title: Re: Connecting RF function gen to AF generator
Post by: ebclr on March 25, 2017, 09:00:17 am
"3 to 4mhz square wave RF carrier"

Conceptual problem here

a 4 Mhz square wave, will have a lot of heavy harmonics, Rf carrier must be sinusoidal if you don't want to use all the rf spectrum for yourself.

If your rf generator does not have a input for modulation you will need
a modulator

something like  this

(http://circuits.datasheetdir.com/315/MC1496-circuits.jpg)
Title: Re: Connecting RF function gen to AF generator
Post by: David Hess on March 27, 2017, 12:42:26 am
Set the 4040A to external AM modulation and apply the modulation signal to the modulation input.  Set the sweep limits and duration as required.