FSK Modulator Carriers 45/55MHz

Thread Starter

Alvaro M

Joined Mar 21, 2017
5
Hey Everyone,

I'm having trouble by finding suitable ICs for my project. I need a FSK or GFSK modulator with data input of 10Mbps and Output of 45 and 55MHz for the 0 and 1 binary values correspondingly. It really is my first electronics project and have been looking for it for a week and can't find anything suitable.

Thank you for the help.
 

Thread Starter

Alvaro M

Joined Mar 21, 2017
5
May be a solution but how's the continuity with that? Thought about a VCO, where the binary data selects which frequency is in its output. Any thoughts about that?
 

BR-549

Joined Sep 22, 2013
4,938
You are looking for a device with a 10 Mbps, fsk, input and a 45-55 MHz fsk modulated output?

Please re-state clearly what you are doing.
 

DickCappels

Joined Aug 21, 2008
6,300
May be a solution but how's the continuity with that? Thought about a VCO, where the binary data selects which frequency is in its output. Any thoughts about that?
Maybe a single counter with 45MHz and 55 MHz outputs.

A PLL can do it. TI has a few set up for FSK but you would have to divide the several hundred MHz output to get down to around 50 MHz. One problem I can see with using a PLL is that the modulation frequency is about 20% of carrier frequency, making getting a snappy response but clean response difficult. Shifting the input voltage open loop into a VCO should work very well.

There were or are some VCOs that can operate well around the frequencies in which you are interested -most of these are in PLL chips today.
 

Thread Starter

Alvaro M

Joined Mar 21, 2017
5
You are looking for a device with a 10 Mbps, fsk, input and a 45-55 MHz fsk modulated output?

Please re-state clearly what you are doing.
Thanks for the reply. What I need is a device with a binary data input of 10Mbps, which modulates that data using FSK, setting the value '0' to a frequency of 45MHz and the binary value '1' to 55MHz.
 

Thread Starter

Alvaro M

Joined Mar 21, 2017
5
Maybe a single counter with 45MHz and 55 MHz outputs.

A PLL can do it. TI has a few set up for FSK but you would have to divide the several hundred MHz output to get down to around 50 MHz. One problem I can see with using a PLL is that the modulation frequency is about 20% of carrier frequency, making getting a snappy response but clean response difficult. Shifting the input voltage open loop into a VCO should work very well.

There were or are some VCOs that can operate well around the frequencies in which you are interested -most of these are in PLL chips today.
Thanks for the rely, I will look for those PLL chips and their specification and will keep you updated
 

Thread Starter

Alvaro M

Joined Mar 21, 2017
5
You mean you want a 44 MHz out for space and 55 MHz out for mark?

I have a little DDS chip with 3 independent outputs. You could set one for 44 continuous and one for 55 continuous and then gate the two with the third output.

https://www.adafruit.com/products/2045
Actually your solution is good but I couldn't find the way to switch between the two output frequencies, according to the data stream.
 
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