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Question about ltspice .measure

Hi,

I simulate a passive high-pass filter with a 1 pF capacitor and a 50 Ohm resistor. I simulate reom 10 to 100 GHz With the waveform tool I measure the -3 dB frequency to be 3.19 GHz and then I tried to measure with a .measure statement from a file. The measure statement I took from the manual:

.MEAS AC tmp max mag(V(out)); find the peak response .MEAS AC meas_3db trig mag(V(out))=3Dtmp/sqrt(2)

The measure report windos tell me: tmp: MAX(V(out))=3D(-0.0043981dB,1.82317=B0) FROM 10 TO 1e+011 meas_3db=3D9.68205e+010 FROM 3.17955e+009 TO 1e+011

What is the number directly behind the =3D? (9.68205e+010)

-- Svenn

Reply to
Svenn Are Bjerkem
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"Svenn Are Bjerkem" schrieb im Newsbeitrag news: snipped-for-privacy@b79g2000hse.googlegroups.com...

Maybe the last before last frequency point in the AC-simulation.

Hello Svenn,

The following command will do what you want.

.ac dec 100 10k 100g

.MEAS AC tmp max mag(V(out)); find the peak response .MEAS AC meas_3db when mag(V(out))=(tmp/sqrt(2))

--- output in the .log file tmp: MAX(mag(v(out)))=(-0.0043981dB,0°) FROM 10 TO 1e+011 meas_3db: mag(v(out))=(tmp/sqrt(2)) AT 3.18011e+009

Best regards, Helmut

LTspice user group:

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Reply to
Helmut Sennewald

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