Hello folks, got a problem for you, and I am willing to award five (5) internets to someone who can help me out here.
I'm an EE intern working on a strain gauge product for my company, and one of the parts of my solution requires the use of a VCO to wirelessly transmit the strain gauge voltage.
I have a few constraints on the system.
-The power supply is only 0-5V
-The output has to be a sine wave
-I want the output frequency to range from 500kHz to 1.5 or 2MHz
-It has to be compact, so the fewer components the better, and they must all be surface mount (though what isn't these days?)
I was looking at using a Wein Bridge oscillator like at this website, however due to the above constraints, I can't really put in a lightbulb for stabilization.
Also, because of the power source limitations, I am not sure if the Wein Bridge will output a sine wave centered at +2.5V, or will even work at all.
The final issue I have is dynamically controlling the frequency itself. I was thinking about replacing the caps in the RC networks with two identical varactors controlled by the strain gauge output, but I cannot find good information on how to design them, and I can't find any prepackaged varactors that have a high enough capacitance.
The strain gauge output will be amplified so that it typically ranges from 1-4V, with 2.5V representing no load.
Alternatively, if anyone is aware of Medium-Wave VCO ICs out there, then that saves us all a lot of trouble.
Sorry for the essay, but I like to be as thorough as possible.
(as an aside, I think this may be better suited in the Projects Forum :I )
I'm an EE intern working on a strain gauge product for my company, and one of the parts of my solution requires the use of a VCO to wirelessly transmit the strain gauge voltage.
I have a few constraints on the system.
-The power supply is only 0-5V
-The output has to be a sine wave
-I want the output frequency to range from 500kHz to 1.5 or 2MHz
-It has to be compact, so the fewer components the better, and they must all be surface mount (though what isn't these days?)
I was looking at using a Wein Bridge oscillator like at this website, however due to the above constraints, I can't really put in a lightbulb for stabilization.
Also, because of the power source limitations, I am not sure if the Wein Bridge will output a sine wave centered at +2.5V, or will even work at all.
The final issue I have is dynamically controlling the frequency itself. I was thinking about replacing the caps in the RC networks with two identical varactors controlled by the strain gauge output, but I cannot find good information on how to design them, and I can't find any prepackaged varactors that have a high enough capacitance.
The strain gauge output will be amplified so that it typically ranges from 1-4V, with 2.5V representing no load.
Alternatively, if anyone is aware of Medium-Wave VCO ICs out there, then that saves us all a lot of trouble.
Sorry for the essay, but I like to be as thorough as possible.
(as an aside, I think this may be better suited in the Projects Forum :I )