Brain Running Slow This A.M. - Time Delay from Laplace ??

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Jim Thompson - 25 Feb 2005 17:52 GMT

My brain is running on slow this A.M.

I can't remember how to calculate time delay versus frequency, given
the Laplace transform.

Please refresh my brain cells.

Thanks!

...Jim Thompson

I love to cook with wine. Sometimes I even put it in the food.

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Rob Gaddi - 25 Feb 2005 18:32 GMT

> I can't remember how to calculate time delay versus frequency, given
> the Laplace transform.

IIRC, L{y(t - d)} = Y(s) * e^(-ds)

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Jim Thompson - 25 Feb 2005 18:42 GMT

>> I can't remember how to calculate time delay versus frequency, given
>> the Laplace transform.
>
>IIRC, L{y(t - d)} = Y(s) * e^(-ds)

That's how to INSERT delay.

Given F(s), what's the time delay versus omega?

...Jim Thompson

I love to cook with wine. Sometimes I even put it in the food.

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Larry Brasfield - 25 Feb 2005 19:06 GMT

>>> I can't remember how to calculate time delay versus frequency, given
>>> the Laplace transform.
[quoted text clipped - 4 lines]
>
> Given F(s), what's the time delay versus omega?

Given your first post, I would have answered as Mr. Gaddi did.
However, it seems now that you want either group delay or
phase delay. Since phase delay is pretty obvious, I'm guessing
it's group delay that you want. Given the Laplace transfer
function, F(s), substitue j*w for s, then take the derivative
of phase with respect to w. That is group delay. (Pronounce
'w' as omega.)

Signature

--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.

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Jim Thompson - 25 Feb 2005 19:11 GMT

>>>> I can't remember how to calculate time delay versus frequency, given
>>>> the Laplace transform.
[quoted text clipped - 12 lines]
>of phase with respect to w. That is group delay. (Pronounce
>'w' as omega.)

Thanks! It's coming back to me.. d(phase)/d(omega)

...Jim Thompson

I love to cook with wine. Sometimes I even put it in the food.

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gwhite - 25 Feb 2005 23:34 GMT

> >>>> I can't remember how to calculate time delay versus frequency, given
> >>>> the Laplace transform.
[quoted text clipped - 14 lines]
>
> Thanks! It's coming back to me.. d(phase)/d(omega)

don't forget the negative sign!:

-dø
GD = ----
dw

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Jim Thompson - 25 Feb 2005 23:57 GMT

>> >>>> I can't remember how to calculate time delay versus frequency, given
>> >>>> the Laplace transform.
[quoted text clipped - 20 lines]
> GD = ----
> dw

But I build only anticipatory circuits ;-)

...Jim Thompson

I love to cook with wine. Sometimes I even put it in the food.

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Rich Grise - 26 Feb 2005 02:25 GMT

>>> Thanks! It's coming back to me.. d(phase)/d(omega)
>>
[quoted text clipped - 5 lines]
>
> But I build only anticipatory circuits ;-)

You mean they finally got that thiotimoline doping process perfected?

;-)
Rich

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Mark Fergerson - 27 Feb 2005 08:12 GMT

>>>>Thanks! It's coming back to me.. d(phase)/d(omega)
>>>
[quoted text clipped - 5 lines]
>>
>>But I build only anticipatory circuits ;-)

> You mean they finally got that thiotimoline doping process perfected?

No, but they're _this close_.

Mark L. Fergerson

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Electronics Forum / CAD / February 2005

Brain Running Slow This A.M. - Time Delay from Laplace ??