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 .ac 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.

[c4757p]

I am not trying to do a .tran simulation; my test is in one pass along time

That's the whole idea of a transient simulation!

AC analysis?

The alternative it to use a behavioral voltage source and put in the equation for the signal you want by hand. I'd go with an AC analysis though.

[atferrari]

I am not trying to do a .tran simulation; my test is in one pass along time

That's the whole idea of a transient simulation!

AC analysis?

The alternative it to use a behavioral voltage source and put in the equation for the signal you want by hand. I'd go with an AC analysis though.

I spent some time reading about the behavioral sources but couldn't come to try anything yet. Any link where to go for read some concrete examples?

[MrAl]

Hi,

There is a VCO in the software.  Use a ramp voltage to control it, that gives a frequency sweep unless it has sweep built in.

[c4757p]

I am not trying to do a .tran simulation; my test is in one pass along time

That's the whole idea of a transient simulation!

AC analysis?

The alternative it to use a behavioral voltage source and put in the equation for the signal you want by hand. I'd go with an AC analysis though.

I spent some time reading about the behavioral sources but couldn't come to try anything yet. Any link where to go for read some concrete examples?

It's just a source that takes an equation directly. Just put in something like V=sin((6.28*time*10k) * time)

[atferrari]

I am not trying to do a .tran simulation; my test is in one pass along time

That's the whole idea of a transient simulation!

AC analysis?

The alternative it to use a behavioral voltage source and put in the equation for the signal you want by hand. I'd go with an AC analysis though.

I spent some time reading about the behavioral sources but couldn't come to try anything yet. Any link where to go for read some concrete examples?

It's just a source that takes an equation directly. Just put in something like V=sin((6.28*time*10k) * time)

Thanks for that! 

[atferrari]

I am not trying to do a .tran simulation; my test is in one pass along time

That's the whole idea of a transient simulation!

AC analysis?

The alternative it to use a behavioral voltage source and put in the equation for the signal you want by hand. I'd go with an AC analysis though.

Sorry. You were RIGHT. What I did not want was exactly that: .ac analysis. My bad.