ENH: NI automatic ramp-down of excitation signal

[klemengit]

It would be beneficial to have an option to automatically reduce the signal at the end with logarithmic decrement or similar. The API would look like this:

gen = LDAQ.national_instruments.NIGeneration(task_gen, signal, decrement)

There are some options to consider before implementing:

• Ramp-up at the start
• Do we add samples with a ramp or decrease the amplitude of the exsiting ones
• The number of the samples in the ramp

All of these could potentially be implemented and controled, however, the intefrace must remain simple and intuitive to use.

[jankoslavic]

This is a nice feature which we usually take care at the side of generated signal; I guess it would make sense to have it also here. We should potentially generate it: rump up/z rump down