i have a problem trying to work with a signal whose amplitude is in nanovolts and has an offset of 1V. LTSpice doesn't plot the amplitude because is too small in comparation to the offset (the amplitude limit for plotting with the offset is 1 micro volt). Is there a way to make LTSpice more sensitive to these little amplitudes or force it to work with the signal? I need to amplify the signal but my amplifier needs the offset to work, and LTSpice does not amplify anything because it does not recognize the waveform because of the little amplitude it has.
Thank you
Best Answer
If you are in Windows, go to the plot display pane of your signal in LTspice. At the top center, there is a nice "net" name there (could be more than one.) Right click on that and a dialog box will pop up. In the bottom half of that dialog box, is an area with a heading that says "Enter an algebraic expression to plot:". Underneath, you will see the equation used, currently. This is probably just a node name, for now. Move your cursor into the box, left click once to get your text cursor, and move around until you are at the end of the node name. Append "-1" to it. (Or some other value.) This will subtract "1" from the signal. (You said the offset is one, so this subtracts that from the signal." Now just click on the "OKAY" button in the upper right. The display will change. Or, if it doesn't seem to, just right click on the data curve itself and click on "Zoom to Fit." That should get it, if it didn't do so otherwise.