How can I set the input signal to LTspice with equal intervals?

Question

In transient analysis I define a voltage input such as a square wave input and obtain an output voltage. Here I set the input signal:

Export time series:

But when I export the input and export time series signals from LTspice as a text, the time points do not have equal intervals. From the text file time plotted:

Is it possible to set it so we have an input and output with equal time intervals? Such as a sampled input and output with a constant sampling rate fs.

I set the max timestep to 0.00008 still same number of samples and same issue nothing change. I think that question is lacking example imao I didnt get the solution which parameter is what ect. — user1245, Nov 20 '17 at 22:10
Can you put your spice file (the netlist file) on pastebin or somewhere? — The Photon, Nov 20 '17 at 22:13
Yes here is the asc file: http://wikisend.com/download/511398/fltrtest22.asc — user1245, Nov 20 '17 at 22:21
@BruceAbbott Because I will use a system identification tool and the tool needs the sampling time(1/fs) to process the data. Related to my previous question: https://electronics.stackexchange.com/questions/340818/obtaining-bode-plots-by-using-laplace-transform-and-time-domain-data-from-spice I will compare the LTspice's Bode plots and the system identification's transfer function. I plan to use it in real scenario. — user1245, Nov 21 '17 at 00:12
Possible duplicate of Exporting LTspice waveforms to txt or csv — Voltage Spike, Nov 21 '17 at 05:52
The problem is not with the input signal, it is with the stimulation time. You can either force the timestep in the .tran command OR use a .meas statment and measure the time that way OR just use the interp function after you load the data into matlab — Voltage Spike, Nov 21 '17 at 05:54

score 1 · Answer 1 · answered Nov 21 '17 at 05:42

1

To 'sample' nodes in LTspice you can use the .WAVE command to create a WAV audio file. The maximum resolution is 32 bits and maximum sampling frequency is 4096MHz.

The plot below was produced from your LTspice schematic. It was created in LTspice with .wave fltrtest22.wav 16 50 V(in) V(out) which specifies 16 bits and 50sps, then converted to csv text data using Sound eXchange (command line: 'sox fltrtest22.wav -t dat fltrtest22.csv'), loaded into Openoffice Calc as merged space-delimited text, and finally plotted on an x-y scatter chart.

answered Nov 21 '17 at 05:42

Bruce Abbott

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Don't forget that the downside of this is the limit between +/-1V. – a concerned citizen Nov 21 '17 at 08:14
Yes, the 'audio' waveforms saturate at +-1V. Just have to set the input to a level that ensures the output doesn't saturate. – Bruce Abbott Nov 21 '17 at 11:51

How can I set the input signal to LTspice with equal intervals?

1 Answers1