Wave view .csv file format

QSPICE
1

Hi Everyone,

I’m struggling a bit with the raw data of the wave viewer of Qspice.
I want to load the data into Matlab to create eventually a pzmap.

I created a simple low pass filter for the wave viewer

This data gets exported to a .csv file seen here:

Raw Qspice Data
Raw Qspice Data570×629 17.2 KB

Then I rework this data in Matlab were I encountered my first weird part of this data.
Because my magnitude to dB is not from voltage to dB but form power to db.

This means that I needed to do 10*log(data points) to get the right magnitude plot.
But the phase part I don’t understand. it looks like its in rad/s. but why does my Matlab plot go back to 0 degrees and not to -90 degrees??

Thank you in advance for your time/attention.

2

This is how the Matlab bode plot looks like.

Bodeplot Matlab
Bodeplot Matlab1919×1073 71.4 KB

3

What function are you using to get phase plot. If you are using arctan, try to use four quadrant arctan like atan2d(y,x)

Best regards,
Ivan

4

I have a project of Matlab2Qspice which can directly read .qraw file (or execute Qspice simulation from .qsch etc…), this save your work in exporting into excel.

Matlab2Qspice : A Matlab scripting interface for Qspice - QSPICE - Qorvo Tech Forum

5

For data format, complex format data (e.g. result from .ac) in Qspice is (Real,Imag)

image
image1897×1003 285 KB

1 Like
6

Thank you, I totally forgot that that also was a possibility. I’m used to LTspice so that’s why the confusion I think.
Another stupid mistake I made in Matlab was not using (./ or .*)with matrixes :sweat_smile:

Thank you guys for your help, I got it fixed in Matlab :innocent:

7

Good to hear your problem solved. As a LTspice user who switched to Qspice, I also experienced confusion initially regarding the export format in Qspice.