Creating Flange or Variable Delay DSP model

[Evo8]

Homework Statement

Im trying to model this in simulink. I am having a little trouble getting things to work. I need to create a variable delay model or basically implement a "flanger" effect.

Flange
A flange is an audio effect, which is achieved by combining two identical signals with each other; the original and delayed signal by a gradually changing amount. The difference equation for the flange effect is given by:
$$x(n)a*[x(n)+x(n-d(n))]$$

Where the time varying delay is given by
$$d(n)=D+\frac{D}{2}[1-sin(\frac{2 \pi f_{d} n}{f_{s}})]$$

Where
- D is a fixed delay,
- fd is the flanging frequency

Homework Equations

N/A

The Attempt at a Solution

So this is what I have right now.

The parameters of the Variable fractional delay block are here:

Im basically trying to mimic that equation with math operators. I am told that it should do the trick. However it doesn't. I am not sure where I am going wrong. Any hints or tips would be greatly appreciated!

Thank you,

E

 

[I like Serena]

I do not have much experience with simulink, but it seems to me that your model should work.

What does it do now?
Or what exactly doesn't it do?