sffm()

Signal frequency FM

Syntax
sffm(time, Offset, Amplitude, CarrierFreq, ModIndex, SignalFreq)


Name	Description	Range	Type	Default	Required
time	Program variable time	[0, ∞)	real		yes
Offset	Offset	[0, ∞)	real	0.0	no
Amplitude	Amplitude of signal	[0, ∞)	real	1.0	no
CarrierFreq	Carrier Frequency	[0, ∞)	real	1/Tstop †	no
ModIndex	Modulation Index	[0, ∞)	real	0.0	no
SignalFreq	Signal Frequency	[0, ∞)	real	1/Tstop †	no
† Where Tstop is StopTime or Envelope Stop

This example assumes that a transient simulation is performed using:
StartTime = 0, StopTime = 3ns, MaxTimeStep = 50ps

This expression creates SFFM pulses repeating periodically at every 1ns until 3ns:
Vsffm = sffm(time, 0, 2, 1GHz)
This expression creates a SFFM pulse using default values for the arguments not listed in the function:
Vsffm_default = sffm(time)
Offset=0, Amplitude=1, Carrier_freq=1/Tstop, Mod_Index=0.0, Signal_freq=1/Tstop

The sffm() function voltage value is calculated as follows:

where fc is carrier frequency, and fs is signal frequency