Hello all,


I have a frequency modulated signal. I would like to determine each period of the FM signal, then determine whether it is above or below a reference period. Based on that decision I would like to either multiply this period with a constant factor or divide by it. Having done that I want to generate a new signal based on the determined periods.
In summary,  I would like to amplify the frequency modulation of a FM signal by either increasing or decreasing each period.

I am not even sure whether this can be done with a real circuit. But, at the moment I want to use VerilogA to implement the above.
The period determination and scaling is not an issue. I was wondering how I can create a new signal based on the obtained period information. I guess I need to create 1 period of this new signal, and then add on another just determined new period.

Can anyone suggest a way?

Regards,
Sven

I am using the following code to determine the periods of a FM signal.



Code:

`include "disciplines.vams"
`include "constants.vams"

module fmeasure (in, out);
input in; voltage in;
output out; voltage out;
real last_time, current_time, freq;

analog begin

    @(initial_step)begin
	last_time = 0.0;
	freq = 0.0;
    end

    @(cross(V(in) -0.5, 1)) begin
	current_time = $abstime;
	if (last_time > 0.0)
	    freq = 1.0 / (current_time - last_time);
	last_time = current_time;
    end
 V(out) <+ freq;
end
endmodule