Radian for frequency in ac analysis

QSPICE
1

How to plot in radian scale (instead of Hz) in ac analysis

2

I assume you meant radian per second (rad/s), where Omega=2*PI*Frequency.
In .AC, .qraw with .alias Freq=Frequency and Omega=(2*PI*Frequency), so change the x-axis quantity to Omega.

Well, the number itself correctly follows Omega, but it still displays Hz as the unit. I will report this to Mike for his review. Currently, you can use Omega/1Hz to remove the unit display.

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3

It works but gives ‘gaps’ at start and end of frequency range.

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ac radian.qsch (4.3 KB)

4
  1. Update Qspice: the alias of Omega is changed to (2*PI*Frequency*1s) in .qraw, indicating that plotting Omega will no longer display a unit in Hz.
  2. To work with Omega, you may still want the x-axis log scale to begin and end with 10 times. My recommendation is to do a trick at start and stop frequency by dividing it with /2/PI.
  3. If the auto-zoom x-axis not fully fitting is bothering you, consider submitting it to Mike for review through email.

ac radian.qsch (4.3 KB)

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5

Update to the latest version of Qspice, and now you can directly plot a Bode plot with the x-axis as Omega using the .abscissa command.
03/20/2026 Implemented a .abscissa command to configure a default parametric plot.
ac radian (.abscissa).qsch (4.3 KB)

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