LTSpice - varying frequency along time

[atferrari]

LTSpice simulation.

I could not find a way to implement this:

a) Testing a circuit fed with a fixed amplitude sinusoidal voltage source varying frequency along a certain period. Say, in 2 seconds, between 6KHz to 450 Hz with 0.5 V amplitude.

b) Later I would like to test the same circuit in the same period at a fixed frequency with a varying amplitude.

c) And last, eventually, mixing both options.

Is such a thing possible? I fear I am out of luck here.

Please note:

I am not trying to do a .tran simulation; my test is in one pass along time and stepping a parameter is not what I need either (well, the way I know to use it, at least...).

Suggestions appreciated.

Edit:
I should have said, .ac simulation. My bad.
/Edit

 

[alec_t]

Have you tried the 'modulate' device (in the SpecialFunctions folder)?
The test you propose sounds like a .tran analysis to me, but you say it isn't?

 

[MikeMl]

 

[MikeMl]

The sim in the previous post is a .Tran. B1 makes a voltage that goes from 0V to 1V as time goes from 0s to 2s. The Modulate behavioral component makes a 2Vp-to-p signal which is 1Hz when the FM input is 0V (space=1) and makes 25Hz when the FM input is 1V (mark=25).

 

[atferrari]

Thanks to you both for replying and sorry for saying the oposite: I was effectively trying to do a .tran simulation (avoiding an .ac simulation).

I understand you call this "a senior moment". We have a couple of colorful expressions on this regard as well.

 

[ericgibbs]

hola at,
Download the Audacity Unicode Audio program, you can make sweep frequencies, chirps, ramps etc as a wave file, then use the wave file in LTS.
To set the amplitude just use a OPA to change the signal level.
Eric
https://www.google.co.uk/url?sa=t&r...IXUq09FvorQJKXfovOmNfWg&bvm=bv.85970519,d.ZGU

 

[atferrari]

hola at,
Download the Audacity Unicode Audio program, you can make sweep frequencies, chirps, ramps etc as a wave file, then use the wave file in LTS.
To set the amplitude just use a OPA to change the signal level.
Eric
https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CC4QFjAA&url=https://audacity.sourceforge.net/&ei=o6rhVKL9Icmf7gbDuYDADA&usg=AFQjCNEjZ2LIXUq09FvorQJKXfovOmNfWg&bvm=bv.85970519,d.ZGU

Gacias Eric,

As soon as I change this clunky PC, I will download it. I became aware of it thanks to you.