SPICE “V” element with “SFFM” option generates a single frequency FM modulated sin wave signal.
The syntax of “SFFM” is as follows.
Berkeley SPICE2, HSpice, PSpice, XSpice, LTspice
Syntax:
Vxxx n+ n- SFFM(VO VA [FC] [MDI] [FS])
VO:offset [V]
VA:amplitude [V]
FC:carrier frequency [Hz]
MDI:modulation index
FS:signal frequency [Hz]
Example:
V1 N001 0 SFFM(0 5 1000 1 100)
The symbol of LTspice’s “V” element with “SFFM” option is “voltage” which is in “C:\Users\Username\Documents\LTspiceXVII\lib\sym” directory. If you want to set the parameters of that by GUI, click “Advanced” button on “Component” menu window and check “SFFM(Voff Vamp Fcar MDI Fsig)” in “Functions” setting.