Hi everyone,

can somebody explain me about SFFM in ltspice, formula, i am searching in google but i dont find something with examples, so i want to do experiments, with difference frequency, because i build all complete circuit for fm, after i want to build it, already i am bussy with one, i mean i buy all the thing i am just building
but this i dont understand

voltage=1V
carrier voltage FM=10.7MEGHZ
modulation index = 22.5
signal = 10KHZ
what is the formula???
thanks goodnight….

 

Be more curious and independent!

 

@Bordodynov
I just tested the asc file, but they are the same Vpp as +1.0Vp and -1.0Vp, so two waveforms covered became one, win 7, the version of LTSpice is the newest one, I just updated yesterday.

 

hi B,
I get the same result as Scott.
Using XP Pro, LTS IV.
E

 

Yes, V (1) = V (2). You see, so that the lines do not merge, I shifted the first line up to 100mV.

 

You can see the FM effect more clearly if you plot V1 (or V2) and also a 1V 10.7meg waveform (V3), over a 100uS sim time.

 

Be more curious and independent!
View attachment 163985

Hi, i realy search on nternet, and i am reading that book in biblotheek about radio, is very good book, but he writte about fm, that i deviation and modulation index, i try to calculate but i dont see any correct result,

because i am asking all long about radio,
so now i have complete everything, i am just making experiments with ltspice, like i say, i am building a superhet fm 1, after when i finish i am gonna build the second fm superhet 2 from the book wich i show, and third the again superhet fm 3 from one site i found,

the next step is to jump to arduino, i have one arduino i try some experiments with basics book and complete arduino pack,

Thank Mannnnn