Add arbitrary waveform together

[qwertyuio0]

Hello everybody,

i'm trying to create a program which produces arbitrary waveforms (non sine, non triangle, non square) from a formule. The number of points of each waveform is determinated by a "random number" into a "for loop", and the number of waveforms is determinated by a second "for loop". My trouble is that the waveforms break at the last point and fall to 0; I want to add them together, i mean add the magnitudes of waveforms. I want to do something like this

two signals , but obiusly with arbitrary waveforms.

[altenbach]

Please don't color the diagram background!

You simply need to sum the waveforms in a shift register instead of using a concatenating tunnel. Of course if you want to add them together, it does not make sense to make them different in lenght.

Please explain.

[qwertyuio0]

Sorry for the color background.

Each waveform represents a current generated by a charge in a diode as efect of radiation (the current is described by the formule). Each waveform has diferent amplitud and length because each charge the diode is different. it means i'm creating many currents. What is important is the area under the waveforms, that's why i want to add them. in fact the waveforms are going to be generated by a Function Generator (here the funcion generator replaces the diode) through GPIB interface. 

[qwertyuio0]

I forgot to say that i would like to take control of each time arrival of each charge. it means a delay between each charge