> On 26 Jul, 20:14, Jerry Avins<j...@ieee.org> wrote:
>> On 7/26/2010 7:16 AM, Rune Allnor wrote:
>>
>>> On 25 Jul, 22:08, "fisico32"<marcoscipioni1@n_o_s_p_a_m.gmail.com>
>>> wrote:
>>>> Hello Forum,
>>
>>>> the Paley-Wiener criterion is the frequency equivalent of the causality
>>>> condition in the time domain.
>>>> It states that the magnitude of the transfer function can be exactly zero
>>>> only a discrete frequencies but not over a finite band of frequencies...
>>>> Why not? Is there a more conceptual explanation for that beside looking at
>>>> the integral and its derivation?
>>
>>> No.
>>
>> I can offer a non-rigorous explanation that is at the root of the
>> rigorous one.
>
> Not at the zero...?
>
>> Every exact zero in the transfer function is the result of a point zero
>> of that function. A zero continuum requires an infinity of point zeros.
>> That is difficult to achieve with limited resources.
>
> To me, this is the same as saying that the integrand
> is not analytic. Which is merely a repharsing of the
> starting position, where one investigates the integral.
Ii is certainly a different way to look at the same information. I had
hoped that fisico might find it more intuitive.
Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
Reply by Rune Allnor●July 26, 20102010-07-26
On 26 Jul, 20:14, Jerry Avins <j...@ieee.org> wrote:
> On 7/26/2010 7:16 AM, Rune Allnor wrote:
>
> > On 25 Jul, 22:08, "fisico32"<marcoscipioni1@n_o_s_p_a_m.gmail.com>
> > wrote:
> >> Hello Forum,
>
> >> the Paley-Wiener criterion is the �frequency equivalent of the causality
> >> condition in the time domain.
> >> It states that the magnitude of the transfer function can be exactly zero
> >> only a discrete frequencies but not over a finite band of frequencies...
> >> Why not? Is there a more conceptual explanation for that beside looking at
> >> the integral and its derivation?
>
> > No.
>
> I can offer a non-rigorous explanation that is at the root of the
> rigorous one.
Not at the zero...?
> Every exact zero in the transfer function is the result of a point zero
> of that function. A zero continuum requires an infinity of point zeros.
> That is difficult to achieve with limited resources.
To me, this is the same as saying that the integrand
is not analytic. Which is merely a repharsing of the
starting position, where one investigates the integral.
Rune
Reply by Jerry Avins●July 26, 20102010-07-26
On 7/26/2010 7:16 AM, Rune Allnor wrote:
> On 25 Jul, 22:08, "fisico32"<marcoscipioni1@n_o_s_p_a_m.gmail.com>
> wrote:
>> Hello Forum,
>>
>> the Paley-Wiener criterion is the frequency equivalent of the causality
>> condition in the time domain.
>> It states that the magnitude of the transfer function can be exactly zero
>> only a discrete frequencies but not over a finite band of frequencies...
>> Why not? Is there a more conceptual explanation for that beside looking at
>> the integral and its derivation?
>
> No.
I can offer a non-rigorous explanation that is at the root of the
rigorous one.
Every exact zero in the transfer function is the result of a point zero
of that function. A zero continuum requires an infinity of point zeros.
That is difficult to achieve with limited resources.
Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
Reply by maury●July 26, 20102010-07-26
On Jul 26, 6:15�am, Rune Allnor <all...@tele.ntnu.no> wrote:
> On 26 Jul, 04:42, HardySpicer <gyansor...@gmail.com> wrote:
>
>
>
>
>
> > On Jul 26, 11:22�am, Tim Wescott <t...@seemywebsite.com> wrote:
>
> > > On 07/25/2010 01:08 PM, fisico32 wrote:
>
> > > > Hello Forum,
>
> > > > the Paley-Wiener criterion is the �frequency equivalent of the causality
> > > > condition in the time domain.
> > > > It states that the magnitude of the transfer function can be exactly zero
> > > > only a discrete frequencies but not over a finite band of frequencies...
> > > > Why not? Is there a more conceptual explanation for that beside looking at
> > > > the integral and its derivation?
>
> > > > Realizable physical system must be causal....Is that always true?
>
> > > Name a non-causal system, then.
>
> > Duhh �- The Tardis of course!
>
> Would be surprised if our friends at the wrong side of the
> pond would be familiar with The Doctor...
>
> Dr Rune- Hide quoted text -
>
> - Show quoted text -
I have a copy of everthing from Hartnell on (at least those that were
not lost). My USB expander is a miniature Tardis.
Jelly baby, anyone?
Maurice
Reply by Clay●July 26, 20102010-07-26
On Jul 26, 7:15�am, Rune Allnor <all...@tele.ntnu.no> wrote:
> On 26 Jul, 04:42, HardySpicer <gyansor...@gmail.com> wrote:
>
>
>
>
>
> > On Jul 26, 11:22�am, Tim Wescott <t...@seemywebsite.com> wrote:
>
> > > On 07/25/2010 01:08 PM, fisico32 wrote:
>
> > > > Hello Forum,
>
> > > > the Paley-Wiener criterion is the �frequency equivalent of the causality
> > > > condition in the time domain.
> > > > It states that the magnitude of the transfer function can be exactly zero
> > > > only a discrete frequencies but not over a finite band of frequencies...
> > > > Why not? Is there a more conceptual explanation for that beside looking at
> > > > the integral and its derivation?
>
> > > > Realizable physical system must be causal....Is that always true?
>
> > > Name a non-causal system, then.
>
> > Duhh �- The Tardis of course!
>
> Would be surprised if our friends at the wrong side of the
> pond would be familiar with The Doctor...
>
> Dr Rune- Hide quoted text -
>
> - Show quoted text -
We are very familiar with Dr Who.
Reply by Rune Allnor●July 26, 20102010-07-26
On 25 Jul, 22:08, "fisico32" <marcoscipioni1@n_o_s_p_a_m.gmail.com>
wrote:
> Hello Forum,
>
> the Paley-Wiener criterion is the �frequency equivalent of the causality
> condition in the time domain.
> It states that the magnitude of the transfer function can be exactly zero
> only a discrete frequencies but not over a finite band of frequencies...
> Why not? Is there a more conceptual explanation for that beside looking at
> the integral and its derivation?
No.
Rune
Reply by Rune Allnor●July 26, 20102010-07-26
On 26 Jul, 04:42, HardySpicer <gyansor...@gmail.com> wrote:
> On Jul 26, 11:22�am, Tim Wescott <t...@seemywebsite.com> wrote:
>
> > On 07/25/2010 01:08 PM, fisico32 wrote:
>
> > > Hello Forum,
>
> > > the Paley-Wiener criterion is the �frequency equivalent of the causality
> > > condition in the time domain.
> > > It states that the magnitude of the transfer function can be exactly zero
> > > only a discrete frequencies but not over a finite band of frequencies...
> > > Why not? Is there a more conceptual explanation for that beside looking at
> > > the integral and its derivation?
>
> > > Realizable physical system must be causal....Is that always true?
>
> > Name a non-causal system, then.
>
> Duhh �- The Tardis of course!
Would be surprised if our friends at the wrong side of the
pond would be familiar with The Doctor...
Dr Rune
Reply by Rune Allnor●July 26, 20102010-07-26
On 26 Jul, 05:48, glen herrmannsfeldt <g...@ugcs.caltech.edu> wrote:
> Jerry Avins <j...@ieee.org> wrote:
> > On 7/25/2010 7:22 PM, Tim Wescott wrote:
> > � ...
> >> Name a non-causal system ....
> > How about getting blamed for something you didn't do?
>
> Before or after you didn't do it?
Before. The term "pre-emptive strike" comes to mind...
Rune
Reply by steveu●July 26, 20102010-07-26
>On 7/25/2010 7:22 PM, Tim Wescott wrote:
>
> ...
>
>> Name a non-causal system ....
>
>How about getting blamed for something you didn't do?
>
>Jerry
Wouldn't it be getting blamed for something you will not have done?
Steve
Reply by glen herrmannsfeldt●July 26, 20102010-07-26
Jerry Avins <jya@ieee.org> wrote:
> On 7/25/2010 7:22 PM, Tim Wescott wrote:
> ...
>> Name a non-causal system ....
> How about getting blamed for something you didn't do?