> PeteS wrote:
> > Rune Allnor wrote:
> >
> > [1] I have a BA in mathematics, and it was stated to me that 'one gets a
> > BA because mathematics is not science, it is one of the arts'.
> >
>
> Hello Pete, whether it is a BA or a BS in math is up to the university
> or the underwriting authority. Many schools offer both with the BA
> trading a few hours of math for a few hours of a language such as
> Spanish, French, German, etc.
>
> IIRC, Newton called Mathematics the Queen of the sciences.
>
> Clay
Well, my memory partially failed me. It was Gauss who wrote
"Mathematics is the Queen of the Sciences"
Clay
Reply by glen herrmannsfeldt●December 14, 20062006-12-14
Jerry Avins wrote:
(snip)
(someone wrote)
>> My guess is that the poster was referring to the fact that a
>> superconducting inductor has no serial resistance, inferring a
>> "perfect" inductor, and made the incorrect jump that a perfect
>> inductor could be used to build a perfect filter-- i.e., his
>> definition of "perfect low pass filter" was not what others in this
>> thread are using. It wouldn't seem like he meant to say that you could
>> use a superconducting inductor to make a brick wall filter.
> You're probably right. I've been jumping at a lot of wrong conclusions
> lately, especially when the wording gives me an initial shove (impulse?)
> in the wrong direction.
Yes, I read it as the inductors weren't perfect causing the filters
to be less than perfect. Still, I am not so sure of the properties
of filters made with superconducting inductors.
-- glen
Reply by Rune Allnor●December 13, 20062006-12-13
DSP Guru skrev:
> "jeff227" <rocksonics@earthlink.net> wrote in message
> news:8cidnVYW8O0zR-PYnZ2dnUVZ_hm3nZ2d@giganews.com...
> > OK, I'm going to really stick my naive neck out on this one...
> >
> >
> > Why isn't the impulse response of a perfect LPF a flat line (i.e., zero)?
> >
> > For example, an infinitely large mass (the filter) hit by an infinitely
> > small particle (the impulse) would not move at all because of its inertia
> > (acceleration goes to zero as masses go to +/-infinity).
> >
> > So why is the impulse response of an infinitely long (perfect) LP FIR a
> > "sinc" function rather than zero?
>
> Nice troll.
>
> Welcome back, Airy.R.Bean!
>
> (Where have you "bean" all this time?)
>
> I've read through the thread and you've certainly got them
> all going again, even getting Jerry Avins to respond in his usual
> (immature?) style.
The only person I have seen use the word "immature" about
others here on comp.dsp, is the very Mr Bean himself...
Rune
Reply by DSP Guru●December 13, 20062006-12-13
"jeff227" <rocksonics@earthlink.net> wrote in message
news:8cidnVYW8O0zR-PYnZ2dnUVZ_hm3nZ2d@giganews.com...
> OK, I'm going to really stick my naive neck out on this one...
>
>
> Why isn't the impulse response of a perfect LPF a flat line (i.e., zero)?
>
> For example, an infinitely large mass (the filter) hit by an infinitely
> small particle (the impulse) would not move at all because of its inertia
> (acceleration goes to zero as masses go to +/-infinity).
>
> So why is the impulse response of an infinitely long (perfect) LP FIR a
> "sinc" function rather than zero?
Nice troll.
Welcome back, Airy.R.Bean!
(Where have you "bean" all this time?)
I've read through the thread and you've certainly got them
all going again, even getting Jerry Avins to respond in his usual
(immature?) style.
Reply by Scott Seidman●December 13, 20062006-12-13
Jerry Avins <jya@ieee.org> wrote in
news:7pydnZAuDqxC0R3YnZ2dnUVZ_uXinZ2d@rcn.net:
> You're probably right. I've been jumping at a lot of wrong conclusions
> lately, especially when the wording gives me an initial shove (impulse?)
> in the wrong direction.
>
> Jerry
Its good training. Much more pleasant doing it here than having a light
bulb going off in your head telling you that you and a client have been
using different definitions for two months!
FWIW, I teach in a biomedical engineering program, and I try my best to
make sure that the undergrads we send out into the world know how to write
and communicate. I'm in the middle of grading term papers now, and that
has me in the habit of casting a big net for definitions, which the
students often let drift.
--
Scott
Reverse name to reply
Reply by Jerry Avins●December 13, 20062006-12-13
Scott Seidman wrote:
> Jerry Avins <jya@ieee.org> wrote in
> news:od-dnUdsho_2gh3YnZ2dnUVZ_rTinZ2d@rcn.net:
>
>> Scott Seidman wrote:
>>> glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in news:O4qdnZdDm-
>>> j1KOLYnZ2dnUVZ_vPinZ2d@comcast.com:
>>>
>>>> Jerry Avins wrote:
>>>>
>>>> (snip)
>>>>
>>>>> But not *every* LPF. Your analogy depends on a "perfect" lowpass,
>>>>> which an inductor is not.
>>>> Superconducting inductors are pretty close, though.
>>>>
>>>> -- glen
>>>>
>>>
>>> When people say "perfect" LP filter, they are usually referring to a
>>> filter with a zero-phase "boxcar" in the frequency domain. They
>>> aren't refering to a filter constructed with "perfect" inductors or
>>> capacitors.
>> Agreed. How do superconducting inductors resemble a brick-wall
>> lowpass?
>>
>> Jerry
>
>
> My guess is that the poster was referring to the fact that a
> superconducting inductor has no serial resistance, inferring a "perfect"
> inductor, and made the incorrect jump that a perfect inductor could be
> used to build a perfect filter-- i.e., his definition of "perfect low
> pass filter" was not what others in this thread are using. It wouldn't
> seem like he meant to say that you could use a superconducting inductor
> to make a brick wall filter.
You're probably right. I've been jumping at a lot of wrong conclusions
lately, especially when the wording gives me an initial shove (impulse?)
in the wrong direction.
Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
Reply by Scott Seidman●December 13, 20062006-12-13
Jerry Avins <jya@ieee.org> wrote in
news:od-dnUdsho_2gh3YnZ2dnUVZ_rTinZ2d@rcn.net:
> Scott Seidman wrote:
>> glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in news:O4qdnZdDm-
>> j1KOLYnZ2dnUVZ_vPinZ2d@comcast.com:
>>
>>> Jerry Avins wrote:
>>>
>>> (snip)
>>>
>>>> But not *every* LPF. Your analogy depends on a "perfect" lowpass,
>>>> which an inductor is not.
>>> Superconducting inductors are pretty close, though.
>>>
>>> -- glen
>>>
>>
>>
>> When people say "perfect" LP filter, they are usually referring to a
>> filter with a zero-phase "boxcar" in the frequency domain. They
>> aren't refering to a filter constructed with "perfect" inductors or
>> capacitors.
>
> Agreed. How do superconducting inductors resemble a brick-wall
> lowpass?
>
> Jerry
My guess is that the poster was referring to the fact that a
superconducting inductor has no serial resistance, inferring a "perfect"
inductor, and made the incorrect jump that a perfect inductor could be
used to build a perfect filter-- i.e., his definition of "perfect low
pass filter" was not what others in this thread are using. It wouldn't
seem like he meant to say that you could use a superconducting inductor
to make a brick wall filter.
--
Scott
Reverse name to reply
Reply by Martin Eisenberg●December 13, 20062006-12-13
Clay wrote:
> PeteS wrote:
>> Rune Allnor wrote:
>>
>> [1] I have a BA in mathematics, and it was stated to me that
>> 'one gets a BA because mathematics is not science, it is one of
>> the arts'.
>
> Hello Pete, whether it is a BA or a BS in math is up to the
> university or the underwriting authority. Many schools offer
> both with the BA trading a few hours of math for a few hours of
> a language such as Spanish, French, German, etc.
>
> IIRC, Newton called Mathematics the Queen of the sciences.
The problem is placing mathematics' object of study. Does our concept
of mathematical truth approximate a property of the universe or is it
a function of the way humans structure their perceptions? The answer
may well be unknowable -- or humanly unknowable if you prefer.
Martin
--
The biggest difference between time and space is
that you can't reuse time. --Merrick Furst
Reply by Jerry Avins●December 13, 20062006-12-13
Scott Seidman wrote:
> glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in news:O4qdnZdDm-
> j1KOLYnZ2dnUVZ_vPinZ2d@comcast.com:
>
>> Jerry Avins wrote:
>>
>> (snip)
>>
>>> But not *every* LPF. Your analogy depends on a "perfect" lowpass, which
>>> an inductor is not.
>> Superconducting inductors are pretty close, though.
>>
>> -- glen
>>
>
>
> When people say "perfect" LP filter, they are usually referring to a filter
> with a zero-phase "boxcar" in the frequency domain. They aren't refering
> to a filter constructed with "perfect" inductors or capacitors.
Agreed. How do superconducting inductors resemble a brick-wall lowpass?
Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
Reply by Scott Seidman●December 13, 20062006-12-13
glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in news:O4qdnZdDm-
j1KOLYnZ2dnUVZ_vPinZ2d@comcast.com:
> Jerry Avins wrote:
>
> (snip)
>
>> But not *every* LPF. Your analogy depends on a "perfect" lowpass, which
>> an inductor is not.
>
> Superconducting inductors are pretty close, though.
>
> -- glen
>
When people say "perfect" LP filter, they are usually referring to a filter
with a zero-phase "boxcar" in the frequency domain. They aren't refering
to a filter constructed with "perfect" inductors or capacitors.
--
Scott
Reverse name to reply