That's the whole point of V2:
it forces LTspice to have a very small timestep indeed.
Obviously it takes time to plot lots of cycles of 1 petahertz.
======================================================================================
Best wishes
John Woodgate OOO-Own Opinions Only
Rayleigh, Essex UK
I hear, and I forget.
I see, and I remember.
I do, and I understand.
Xunzi (340 - 245 BC)
On 2023-07-16 22:53, Bell, Dave wrote:
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Andy, your model here does work all the way
down to 1fs.
But:
- It¡¯s much
slower as-is, so
- I deleted
the SIN source, V2/B
Now, it runs as fast as before, as far as I
could sense (didn¡¯t compare runtime in the logs), but no
longer works below 10ps!
?
Dave
?
?
For grins,
here is another one to try.? It shows one way to control
SPICE's internal timestep while not imposing a harshly small
Maximum Timestep across the whole simulation (which would make
it crawl):
V1 A 0 PULSE(0 1 4m {Trf} {Trf} 1m 2m)
V2 B 0 SIN (0 1 1000T 4m 0 0 1000)
.step param Trf list 1f 10f 11f 20f 50f
100f 1p
.meas T0 WHEN V(A)=0.01 rise=1
.meas T1 WHEN V(A)=0.99 rise=1
.options
plotwinsize=0
? ? ?1 1.01915e-015? <-- 1.02 fs
? ? ?2 9.80032e-015? <-- 9.8 fs
? ? ?3 1.07796e-014? <-- 10.8 fs
? ? ?4 1.95998e-014? <-- 19.6 fs
? ? ?5 4.90007e-014? <-- 49.0 fs
? ? ?6 9.79997e-014? <-- 98.0 fs
? ? ?7
9.8e-013? <-- 0.98 ps
Andy
John Woodgate