Not a graph, but a start
Here's a file...maybe you've already done this, in which case, my apology for the redundancy. A typical kind of amp, and I sweep the drive level. If you look in the Spice error log file (view=>spice error log), you see the output distortion.
I know you wanted a graph, but maybe this is a useful stop along the way.
unzip the model file and the .asc file into the same directory, and run the test case.
Here's a file...maybe you've already done this, in which case, my apology for the redundancy. A typical kind of amp, and I sweep the drive level. If you look in the Spice error log file (view=>spice error log), you see the output distortion.
I know you wanted a graph, but maybe this is a useful stop along the way.
unzip the model file and the .asc file into the same directory, and run the test case.
Here's that Graph!
The enclosed zip file contains a pdf file that describes what's going on in the enclosed LTSpice files.
In a nutshell, it lets you make plots of THD versus input level in LTSpice.
Given this example, you could probably also do THD plots versus frequency, but I haven't tested that. I thought I'd get feedback on the original question first before continuing.
I hope this is useful, and clearly enough documented to be understandaable. Feedback is appreciated.
Dan
The enclosed zip file contains a pdf file that describes what's going on in the enclosed LTSpice files.
In a nutshell, it lets you make plots of THD versus input level in LTSpice.
Given this example, you could probably also do THD plots versus frequency, but I haven't tested that. I thought I'd get feedback on the original question first before continuing.
I hope this is useful, and clearly enough documented to be understandaable. Feedback is appreciated.
Dan
It is understandable , but the subcircuit part of it would be problematic to implement with a much larger circuit. It is redundant. thanks for the idea ... I don't know to what level I will abuse it yet. 😀
I have the level stepped and can see both my fourier and error log total THD , therefore I can see the data I need (below 1). It would be a lot of work just to get a handy (level vs. THD graph). 😱 It seems a shame , as I have the total THD data stepped in the log , that it could not be directly plotted out versus the stepped levels.
OS
The FFT with multiple steps shows the progression of H2 -9 as output increases , which is still quite useful.
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One more link to solution http://www.diyaudio.com/forums/software-tools/202522-ltspice-thd-analyzer.html
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