How to write a High-Pass and Low-Pass filter as soon as possible?

On Sun, 20 Nov 2005 15:13:33 -0600, Richard Owlett
<rowlett@atlascomm.net> wrote:

>Jerry Avins wrote:
>> There are plenty of plumbers who don't know (or at least can't 
>> explain) how a pipe wrench works.
>>
>
>Much truth in "Those who can, do. Those that can't, teach."
>

Hi Richard,

  My Book of Quotations attributes that quote to 
George bernard shaw.

I like this one:

   "He is either dead, or teaching school."
                        --Zenobius (1st century B.C.)

[-Rick-]

Jerry Avins wrote:

(snip)

> A good teacher at any level, especially the more elementary ones, needs 
> to know how it is possible not to understand. This is particularly true 
> with math. "I explained it already, so now you know" is never overt, but 
> all too common anyway. It takes a very special person to understand a 
> subject thoroughly and yet understand a student's difficulty. Many 
> people teach, but only such a person is a Teacher.

I can remember at least a few times explaining something to my son, and 
when he didn't understand it the first time realizing exactly how it was 
that he didn't understand it.  I knew, then, how to make the right 
explanation.

I remember when he was learning to read and would see a word spelled 
similar to a more common word, and reading the more common word instead.
Knowing both words, it was then obvious to me what the right word was.

-- glen

Jerry Avins wrote:
> dbell wrote:
> > Richard,
> >
> > I am not a teacher, never have been one (a paid one anyway, I am not
> > counting posting or mentoring).  I grew up hearing
> >
> > "Those who can, do. Those that can't, teach."
> >
> > I think it is wrong.  Naive at best. Teaching IS doing something, it is
> > 'teaching'.  An professor does not have to be an experienced
> > practicioner in the same field.  His/her joy, purpose, or productivity
> > may be in impacting students in an educational environment rather than
> > being a practitioner in an engineering environment.  It can be an
> > entirely different job, with huge differences in environment,
> > satisfaction, .... Some professors obviously do both (some of them post
> > here), and some do more engineering (research, advising) than teaching.
> >
> > As far as the math professors that you mentioned, if the advanced grad
> > students thought they were great, maybe the professor was bored with
> > teaching elementary calculus to your average undergrads with their
> > predictable questions and confusions, and got the intellectual
> > stimulation or achievement needed with higher level subject matter and
> > more serious grad students. I have heard that sentiment expressed
> > before. It is not a perfect world.
>
> A good teacher at any level, especially the more elementary ones, needs
> to know how it is possible not to understand. This is particularly true
> with math. "I explained it already, so now you know" is never overt, but
> all too common anyway. It takes a very special person to understand a
> subject thoroughly and yet understand a student's difficulty. Many
> people teach, but only such a person is a Teacher.

My approach when dealing with intermediate-level students (haven't
taught
beinners), is to ask them to explain to me in their own words how they
see
whatever subject is dicussed. It only works when talking with one or
two 
students at the time, though.

Rune

Rune Allnor wrote:

> My approach when dealing with intermediate-level students (haven't
> taught beinners), is to ask them to explain to me in their own words how they
> see whatever subject is dicussed. It only works when talking with one or
> two  students at the time, though.

It depends.  I've used a similar approach in a larger class size, and
it seems to work OK. The trick is to get one or two of the more vocal
students talking about the problem, then other, less confident,
students tend to join in the conversation.

I agree, though, that it doesn't scale well.

Ciao,

Peter K.

glen herrmannsfeldt wrote:
> Jerry Avins wrote:
> 
> (snip)
> 
>> A good teacher at any level, especially the more elementary ones, 
>> needs to know how it is possible not to understand. This is 
>> particularly true with math. "I explained it already, so now you know" 
>> is never overt, but all too common anyway. It takes a very special 
>> person to understand a subject thoroughly and yet understand a 
>> student's difficulty. Many people teach, but only such a person is a 
>> Teacher.
> 
> 
> I can remember at least a few times explaining something to my son, and 
> when he didn't understand it the first time realizing exactly how it was 
> that he didn't understand it.  I knew, then, how to make the right 
> explanation.
> 
> I remember when he was learning to read and would see a word spelled 
> similar to a more common word, and reading the more common word instead.
> Knowing both words, it was then obvious to me what the right word was.


It's also important not to unteach. "I do it this way" instead of 
"That's wrong." When my oldest son first learned to about numbers, he 
didn't use them to count objects. Given a few nuts, he would move them 
to a pile one or two at a time, saying "One, one, two, one," contemplate 
the pile for a bit, then announce "Five!" It would have been sinful to 
"correct" him.

He did know how to progress from one number to the next, and could 
accurately count as high as he had time for. It was to him simply the 
sequence of successively larger groups. About the time he could stare at 
a group of ten things for a while and know its number, he also had 
acquired enough words so I could tell him that if he named each unit the 
next counting number in turn, the name of the last one would be the 
number of the group.

In a deep sense, he was right and the rest of us miss the point. I let 
him teach me and we're both the better for it.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

Jerry Avins <jya@ieee.org> writes:

> In a deep sense, he was right and the rest of us miss the point. I let
> him teach me and we're both the better for it.

That's one thing I found great about teaching: if you do it properly,
the teacher learns as much (or more) than the taught.

Having said that, one thing that disappointed me about some students
was the attitude implied by this para-phrased saying:

Give someone a fish; feed them for a day.
Teach someone how to fish; they'll ask if fish roe is on the exam.

:-(

I suppose there is a difference between learning for the sake of it
and having to show at a predefined time (finals) that you learnt specific
things (DSP101).

Ciao,

Peter K.

Peter K. wrote:

   ...

> That's one thing I found great about teaching: if you do it properly,
> the teacher learns as much (or more) than the taught.
> 
> Having said that, one thing that disappointed me about some students
> was the attitude implied by this para-phrased saying:
> 
> Give someone a fish; feed them for a day.
> Teach someone how to fish; they'll ask if fish roe is on the exam.
> 
> :-(

But we adults teach them to think that way. :-(

> I suppose there is a difference between learning for the sake of it
> and having to show at a predefined time (finals) that you learnt specific
> things (DSP101).

Sure, but often, we define the times wrongly. I think it's better to 
have final exams long after the course is over, so that knowledge, 
rather than ability to cram and forget is tested.

It's been shown over and over that middle- and high-school kids learn 
better when they can sleep in, yet they're rousted out of bed at 6 AM so 
the buses can be reused later for elementary-school kids. Keep the 
elementary classes at the present time and starting the older kits after 
consistently raises test scores, but it's rarely done.

Predefined time is often the wrong time.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

Jerry Avins <jya@ieee.org> writes:

> 
> But we adults teach them to think that way. :-(
>

Yes, I suppose you're correct.  It's a pity. I rarely take that
attitude (do the minimum to get by; oh, and will you tell me what the
minimum minimum is?).
 
> Sure, but often, we define the times wrongly. I think it's better to
> have final exams long after the course is over, so that knowledge,
> rather than ability to cram and forget is tested.

That's one reason I used to have a quiz in the second week of
semester... on the pre-requisite course material. To see how much
stuck.

> It's been shown over and over that middle- and high-school kids learn
> better when they can sleep in, yet they're rousted out of bed at 6 AM
> so the buses can be reused later for elementary-school kids. Keep the
> elementary classes at the present time and starting the older kits
> after consistently raises test scores, but it's rarely done.
> 
> Predefined time is often the wrong time.

Almost surely.

Ciao,

Peter K.