Generate a variable sine wave during simulink simulation

Hi,

I want to generate a sine which amplitude and delay is changing during a simulation.

From this formula:

 out = M * sin(2*pi*50*t + (pi*phi/180)))

I want to change M and phi.

I've tried to generate it using blocks but I am stucked in the sine part. I've tried using a gain but it gives me an error.

The perfect solution for me will be to use the sine wave block and change the variables on the block through an external variable.

Many thanks.

Answer 1

[Kaustubha Govind]

The Sine Wave block from the Simulink>Sources library does not accept any inputs, so you cannot use this block to change 'M' and 'phi' as you intend. Instead, you should use the MATLAB Function block to implement the same equation while accepting 'M' and 'phi' as inputs to the block.

[Guy Rouleau]

Personally, I would not use the MATLAB Function for that. I would use the Trigonomeric Function, Product, Gain and Sum block:

http://www.mathworks.com/help/simulink/slref/trigonometricfunction.html

That way you will avoid the need for the MATLAB Function block to generate code.

[Kaustubha Govind]

I agree!

[Dani Tormo]

That was I was looking for.

Many thanks!

[Guy Rouleau]

Thanks for sharing the image, that's what I meant. One minor suggestion. You can replace the Product and 1/360 Constant by a Gain block. This will not have significant effects on your small model, but in general the less blocks in a model the better it is. This is especially true on the update time.

[Vaibhav Banajwade]

Thank you for the answer. I was also looking for it. But I didn't understand why the "clock" is used.