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From: Speed axs on 21 Sep 2009 14:58
Hello All,

I am using simulink to generate phase noise. Basically I have a since wave generator and want to introduce phase noise to this. Surprisingly I haven't found a phase shifter block in simulink. I even didnt find an Allpass filter.
One other related issue I have is to generate a constant 90 degree phase shift (generate a cos signal). I do not want to introduce a new sine generator with a phase shift. I want to be able to use a single sine generator, then phase shift it by 90 degrees to get separate sine and cos signals.
I am working with continuous time signals. I a constant phase shift (to generate cos signals), I even tried taking derivative (I get the 90 degrees shift but a weird gain ...which is not omega times the signal like what we expect - d(sinwt)/dt = wcoswt). I even tried to create a basic all pass filter using the transfer function block with the fn as (s-1)/(s+1), still I dont get a 90 degree phase shift.

Please help me with these to concerns.
1. To introduce a constant phase shift of 90 degrees
2. To be able to generate a random pahse shift.

I can play around and get the solutions even if I get to know the solution for one of the above points. Only point to be noted is that it has to be in Simulink and not using matlab code.

This is my first post in this forum. Hope to get some positive responses.

Thanks s lot for your time and support,

With best regards,
Speed
From: Phil Goddard on 21 Sep 2009 17:54

Us the Variable Time Delay block (from the Continuous library).
Feed your sine wave into the first input and a th amount of delay you want into the second.

Phil.
From: Speed axs on 21 Sep 2009 19:15
Thanks a lot Phil for the quick and apt response. It works perfectly fine. I am now surprised why the other methods didnt work.

Anyways, once again thanks a lot.

Woth best regards,
Speed

"Phil Goddard" <philNOSPAM(a)goddardconsulting.ca> wrote in message <h98sls$irl$1(a)fred.mathworks.com>...
>
> Us the Variable Time Delay block (from the Continuous library).
> Feed your sine wave into the first input and a th amount of delay you want into the second.
>
> Phil.
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