TINA TI: Square wave voltage source, signal truncated. Why?

Hi Michael,

I can duplicate what you are observing on my end as well.

I know that I can "fix" the issue, but I don't know the reason behind it.

To fix the waveform:

Go to Analysis, "Set Analysis Parameters" and change "TR excitation subdivisions" from default "10" to "1000" and the waveform then looks good, as shown below.

Regards,

Hooman

Michael,

The reason behind this is that the calculation of the waveform in the voltage probe (or voltage meter) is based on samples and the alogrithm uses a weighted sum of those samples. When there is an abrupt change in the source voltage,  a discrepancy like this can occur unless the time step is set sufficiently small (by default the adaptive time step that is being used cannot prevent this from happening). In a normal circuit, there are other reactive components that will smooth out this behavior. If you are simply interested in the voltage or current  from a source, it is recommended that you use the Draw excitation option at the Transient Analysis to see the source waveform and use the voltage probe at other nodes only. As Hooman pointed out, increasing the samples to 1000 will fix the problem. You can also change the maximum time step to 10n and that will fix this as well.

Britt