Electronics > Beginners
Phase Measurement in LT Spice
eev_carl:
Hi,
Am I applying this .meas directive correctly? I'm trying to get the phase angle between the two sine waves. On the scope, I measured this at about 80 degrees but am getting 63 degrees from .meas.
Thanks,
Carl
Ian.M:
Attach your sim as a .asc file so others can check it easily.
eev_carl:
Here's my .asc
eev_carl:
Also, with regards to the scope picture...the yellow sine wave is a direct connection from the function generator. I'm using a BNC splitter. The other half of the splitter goes to the circuit. The blue sine wave is at the junction of the R and the E.
Ian.M:
Why did you strip the .measure commands?
--- Code: ---.meas TRAN TIME_1 TRIG V(Vin)=0 RISE=2 TARG V(Vin)=0 RISE=3
.meas TRAN TIME_2 TRIG V(Vin)=0 RISE=2 TARG V(Vout)=0 RISE=2
.meas phase param 360*(TIME_2/TIME_1)
--- End code ---
With the .tran 0 1m .5m command from the sim you attached, I am also getting about 80 deg, confirmed by cursor measurements. With your original .tran 50m I'm getting the same bogus 63 deg you got.
I suspect the cause is too many cycles and not enough data points due to your initially ill-chosen simulation duration.
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