Hi I was wondering if anyone has some code that they can give me or the basics that will step up the voltage of a microprocessor so that I can broadcast from a VCO on multiple frequencies.

 

I have no idea what you're trying to do.

 

Oh sorry. Ok so basically I want to use a VCO and have it step up frequencies like starting at 500 mhz and go up to like 2000 mhz then go back down again then back up and so on... So the question is how do I code the microprocessor so that it will output voltage to the VCO so that the VCO changes frequencies in that pattern?

 

Oh sorry. Ok so basically I want to use a VCO and have it step up frequencies like starting at 500 mhz and go up to like 2000 mhz then go back down again then back up and so on... So the question is how do I code the microprocessor so that it will output voltage to the VCO so that the VCO changes frequencies in that pattern?

It would help greatly if you had a part number or a link to a datasheet so we can see if the VCO is "controllable" by a microprocessor. RF work at 2GHz. is not for the faint of heart. Do you have the test equipment to support these experiments?

Why are you playing with such a wide spectrum. There are two amateur bands in that range at 900 MHz and 1296 MHz. Tell us again what you're trying to accomplish by sweeping a VCO over such a range.

 

Nvm I changed the frequencies. But I still need the code to step up voltage from .5 to 4.5v. The VCO is here http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CVCO55CL-0830-0970-ND
and I'm not really sure what processor to use If someone could point me to one http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=2556260&k=microprocessor it would really help. Thx

 

You were not exactly clear about what you had in mind. You said you needed code to step up the voltage from 0.5V to 4.5 Volts. What you meant was that you need a way to vary the control voltage to the VCO over that range. A microprocessor does not usually have a built in DAC (Digital to Analog Converter). You can add one however and each and every choice of a DAC will require different code. You could also generate a control voltage by using PWM (Pulse Width Modulation) and low pass filtering. Befor we charge off and write code let us decide how the control voltage will be generated.

You do realize that the VCO has a much narrower bandwidth than you indicated in your original post. I'm still curious about what you are up to since it looks like you are in way over your head.

 

Oh umm.. well can you explain what the Digital to Analog converter does? and yes I realize that the VCO frequency range is not what I originally had. But I already got past that problem.

 

What is the device you're trying to build for?

 

Hello,

To cover the range from 500 to 2000 Mhz you will need 4 VCO's.
You will need to switch between the VCO's to have the full range.
See the datasheets for more info.

Greetinhs,
Bertus

 

Oh umm.. well can you explain what the Digital to Analog converter does? and yes I realize that the VCO frequency range is not what I originally had. But I already got past that problem.

Well it does pretty much what its name implies. It converts a number in digital form to an analog voltage. If you change the value of the digital word that you write to the device then the analog voltage coming out changes as well.

I still would like to know what you are trying to do. I'm sure we could come up with better answers if we knew.