From: Randy Yates on
Mikolaj <sterowanie_komputerowe(a)> writes:

> on 07-04-2010 o 13:53:36 glen herrmannsfeldt <gah(a)> wrote:
> (...)
>> I believe that in some cases complex physical quantities
>> that are in exponents have a physical interpretation.
>> As examples, the dielectric constant and its square root,
>> the index of refraction. Other than in exponents,
>> the use of complex numbers for physical quantities,
>> such as describing phase shifts, seems more of a
>> convenience, and not something with a physical
>> interpretation.
> (...)
> It seems that sometimes, luckily
> when you use complex (compressed, packed, combined, compact)
> way of describing few dependent physical things
> their imaginary part (additional dimension used for compression)
> can be human understandable
> and could have interpretation.
> But you can always decompress complex matrix
> to it's scalar version equations.

You can "decompress" modulo arithmetic as well; does that
make it any less of a distinct arithmetic system?
Randy Yates % "And all you had to say
Digital Signal Labs % was that you were
mailto://yates(a) % gonna stay." % Getting To The Point', *Balance of Power*, ELO
From: Mikolaj on
On 10-04-2010 at 19:51:37 Randy Yates <yates(a)> wrote:

> You can "decompress" modulo arithmetic as well; does that
> make it any less of a distinct arithmetic system?

Modulo arithmetic is of the same kind the imaginary number is.
It is a tool.
Describing physical world
is on a diffrent level of abstraction.
We use tools for description.
Sometimes our tools fit to some parts of physical laws.
We want them to fit.
But the nail doesn't fit and doesn't represent the whole house.
We could decomposite house
but if we decomposite nail
we will be talking on a different level of complexity.

It's a bit messy philosophy.
Let's stay close to the main subject.
Does imaginary FIR coefficients fit, in any way, to reality.

From: kadhiem on
>What is the physical significance of having an impulse response with
>complex coefficients ie
>{h0,h1,} where the h values are complex.
Regarding original question...
My perspective is the case you want to shape baseband signal asymmetrically
when upconverted to RF. A real filter cannot do that but a complex pair