Author Topic: Using frequency generators to create and modulate carrier waves  (Read 652 times)

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Offline altnergyTopic starter

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Hello! I have several frequency generators DDS 60Mhz units.

I know how to program sweeps and all the common stuff I want to do.

What I want to know is EXACTLY how to CREATE a carrier wave, then modulate it. I have found DOZENS of videos etc. that explain the theory behind carrier waves and history etc. BUT NOBODY has yet explained something as simple as HOW to do the following.
So I Am going to give a very simplified example of what I would like to learn how to do.

In explaining this PLEASE show me or tell me EXACTLY what to connect to where and in order to make this happen.

1) Create a 1MHz signal
2) Modulate it with a 1KHz signal

I have a sweep programmed in one unit that goes from 100Hz to 150MHz. I want to also modulate the 1MHz signal with that sweep.

Thank you in advance for ANYONE who is willing to show me hot to do this. If TWO Signal Generators are required I do have identical Feeltech FY6900 units we can use for the learning experience!

I have experience over the past several decades building medical equipment, and musical gear from component level electronic parts, synthesizers and such, etc. etc. etc. Also ran my own computer I.T. Business since 1995 with clients like Met Life, AMEX, FBI, U.S. Senate, BAnks, Airlines, Xerox, Kodak, etc.

All this forum stuff is new to me and I admit not to quite understand it all and get distracted with so many options, emogies and such.

So please any who can help me let us just respond with simple communication one mind to another. I follow instructions well and love to learn. Photos and diagrams are helpful.

God bless and be well!
 

Offline Benta

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Re: Using frequency generators to create and modulate carrier waves
« Reply #1 on: June 22, 2022, 11:17:57 pm »
Dunno what kind of modulation you want (AM, FM, PM...), but it seems the FY6900 can do it all by itself.
Set CH1 to 1 MHz, and use CH2 for 1 kHz modulation.

 

Offline TimFox

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Re: Using frequency generators to create and modulate carrier waves
« Reply #2 on: June 22, 2022, 11:20:15 pm »
The first question:
Do you want to make a "DSB, suppressed carrier" output, or an
"AM, with carrier" output when modulating the 1 MHz carrier with the 1 kHz "baseband"?
The former (DSB) can be expressed as
V(t) = A x sin(w1t) x sin(w2t)
The latter (AM) can be expressed as
V(t) = A x sin(w1t) x [1 + Bsin(w2t)]
where w1 = 2pi x (carrier frequency) and
 w2 = 2pi x (baseband frequency)
 

Offline mag_therm

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Re: Using frequency generators to create and modulate carrier waves
« Reply #3 on: June 23, 2022, 04:21:17 pm »
If you want to do it on pcb, look at the datasheets for the MC1496 and the SA612A.
Both have sample circuits and details of how you could use your generators as sources of carrier and signal.
 


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