Frequency Mod

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This block is an input amplitude controlled complex sine. It outputs a signal, which has a momentary phase increase that is proportional to sensitivity and input amplitude.

More specifically, takes a real, baseband signal (x_m[n]) and output a frequency modulated signal (y[n]) according to:


Where x[n] is the input sample at time n and is the frequency deviation. Common values for are 5 kHz for narrowband FM channels such as for voice systems and 75 KHz for wideband FM, like audio broadcast FM stations. In this block, the input argument is, not the frequency deviation. The sensitivity specifies how much the phase changes based on the new input sample. Given a maximum deviation, and sample rate, the sensitivity is defined as:



(R): Run-time adjustable

Sensitivity (R)
radians/sample = amplitude * sensitivity

Example Flowgraph

NFM xmt 2 fg.png

Source Files

C++ files
Header files
Public header files
Block definition