Replacing three integrators with one

Question

I need to calculate a linear growth model (in simulink) with continuous-time signal, described as:

x’ = ax

with at least three different real parameters “a”.

I've managed to do it using three integrators as you can see in the image below:

I've been told that there is a way to do it using only one integrator, but I can't figure it out.

Answer 1

You can give your gain blocks a vector, not just a scalar.

You can use a gain of [1 0.8 1.2] for a single gain block (with the multiplication mode set to Element-wise) instead of having three separate gain blocks set to 1, 0.8, and 1.2.