Frequency Modulation trick. How to solve?

[ACiDuser]

Hello!

I have a VI which does Frequency modulation using two formula nodes. One node is for Message signal generation and second formula node - is for resulting FM generation. Observing FM equations, the function inside FM equations - should be instegrated and FM is like:

 FM(t) = A*cos(2*pi*Fc + 2*pi*D* Integral( M(t) );

, where A - amplitude; pi - 3.14; Fc - Carrier frequency, M(t) - message signal; D - frequency deviation.

 Thats why I use external Integration, then pass integrated signal into FM equation.

 The problem is - Signal has very low voltage (amplitude) after integration - and the whole thing doesn't work anymore.

 Should I multiply integrated signal until it be the same amplitude as the original signal?

 What might I did incorrect here?

Thanks in advance. 

[ACiDuser · Accepted solution]

I have created a Polymorphic VI "FM Generation". This VI Generates Frequency Modulated signal output according to wired Message signal. FM Generation VI accepts two types of Message signal input - Waveform or Array. If you wire an array for Message intput - you also need to wire "Sampling Frequency" input. Now every one can place this polymorphic function on their Block-Diagram palette and use it.

Note: You should place on a block diagram VI called "FM Generation.vi", two other files "FM Generation (array).vi" and "FM Generation (waveform).vi" are function instances that are responsible either for Waveform input or Array input.

 This function is designed for LabView 7.1 or higher.

Feel free to write feedbacks. 

[ACiDuser]

Found a couple of errors and quickly fixed them, so now it's working ok.