Interpolate between two signals in Simulink

I only need to interpolate between two signals. The signals are just calculations for flow rate needed based off altitude. So signals are as follows: 1. Flow rate needed at 47500ft and above in altitude 2. Flow rate needed at 23000ft and below in altitude I just need to interpolate between the signals (ex: 35000ft) to get the needed value, where altitude is always known. The flow rate is calculated with variables that can be changing.

[Eric Stewart]

I ended up making a simple linear interpolation subsystem. Kept looking for a block to do this, but my subsystem does the job for me.

Answer 1

[Aquatris]

Here is how linear interpolation works;

y1 = 10; % known flow rate for 47500 ft
y0 = 2;  % known flow rate for 23000 ft
x1 = 47500; % constant altitude
x0 = 23000; % constant altitude 

x = 35000; % variable altitude
y = y0 + (x-x0)*(y1-y0)/(x1-x0); % needed flow rate
plot([x0 x1],[y0 y1],x,y,'o')

Implement it using the constant blocks and math operation blocks.