Well Jerry he's half right. Maybe he should reread the subject line ...
I don't see a capital J in there at all :)
Cheers,
David
Jerry Avins wrote:
> Neo wrote:
>
>> I is the inphase component and J is the quadratrature phase component.
>
>
> It doesn't matter that he repeated it. Ignore it anyway.
>
> Jerry
Reply by Jon Harris●March 10, 20052005-03-10
"Jerry Avins" <jya@ieee.org> wrote in message
news:beOdnRDuWdvF6a3fRVn-hQ@rcn.net...
> Neo wrote:
> > I is the inphase component and J is the quadratrature component.
>
> Ignore that nonsense. (What is K?)
I = In-phase, Q = Quadrature, j = sqrt(-1)
Reply by Jerry Avins●March 10, 20052005-03-10
Neo wrote:
> I is the inphase component and J is the quadratrature phase component.
It doesn't matter that he repeated it. Ignore it anyway.
Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
Reply by Jerry Avins●March 10, 20052005-03-10
Neo wrote:
> I is the inphase component and J is the quadratrature component.
Ignore that nonsense. (What is K?)
Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
Reply by Jerry Avins●March 10, 20052005-03-10
Andre wrote:
> I guess the missing part is that the math peoples i (imaginary element)
> is called j in electrical engineering to avoid mixup with the current i.
Mix-ups are so very easy! If I didn't know better, I could assume that
"current i" above refers to i as it is now, as opposed to what it might
become. (Anyone still confused should read "the current i" as "the
symbol 'i' that is used to represent electrical current.") Oh my!
Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
Reply by Neo●March 10, 20052005-03-10
I is the inphase component and J is the quadratrature component.
Reply by Neo●March 10, 20052005-03-10
I is the inphase component and J is the quadratrature phase component.
Reply by Andre●March 10, 20052005-03-10
I guess the missing part is that the math peoples i (imaginary element)
is called j in electrical engineering to avoid mixup with the current i.
Randy Yates wrote:
> "Dr. Thomas Radtke" <thradtke@freenet.de> writes:
>
>
>>george_barr@yahoo.com schrieb:
>>
>>>This is regarding the DSP math/equations in general. What is "x = I +
>>>jQ"? I know that j = 0 + 1i and i = sqrt(-1) and i^2 = -1. But what
>>>is x = I + jQ, where x represents a form of the input data signal.
>>>I need this info to calc the atan(Q/I) for frequency demodulation
>>>purposes. Any help is appreciated.
>>>
>>
>>x is just a complex number. Since I and Q are real, you should have no
>>problems calculating your formula.
>
>
> Also note that a complex number can be expressed in rectangular form,
>
> z = x + i*y
>
> or polar form
>
> z = r*e^{j*theta},
>
> where
>
> r = |z| = sqrt(x^2 + y^2}
> theta = angle(z) = arctan(y/x),
>
> the usual rectangular-to-polar conversion.
--
Please change no_spam to a.lodwig when replying via email!
Reply by Randy Yates●March 10, 20052005-03-10
"Dr. Thomas Radtke" <thradtke@freenet.de> writes:
> george_barr@yahoo.com schrieb:
>> This is regarding the DSP math/equations in general. What is "x = I +
>> jQ"? I know that j = 0 + 1i and i = sqrt(-1) and i^2 = -1. But what
>> is x = I + jQ, where x represents a form of the input data signal.
>> I need this info to calc the atan(Q/I) for frequency demodulation
>> purposes. Any help is appreciated.
>>
>
> x is just a complex number. Since I and Q are real, you should have no
> problems calculating your formula.
Also note that a complex number can be expressed in rectangular form,
z = x + i*y
or polar form
z = r*e^{j*theta},
where
r = |z| = sqrt(x^2 + y^2}
theta = angle(z) = arctan(y/x),
the usual rectangular-to-polar conversion.
--
% Randy Yates % "And all that I can do
%% Fuquay-Varina, NC % is say I'm sorry,
%%% 919-577-9882 % that's the way it goes..."
%%%% <yates@ieee.org> % Getting To The Point', *Balance of Power*, ELO
http://home.earthlink.net/~yatescr
Reply by Mike Yarwood●March 10, 20052005-03-10
"Dr. Thomas Radtke" <thradtke@freenet.de> wrote in message
news:422FFB0A.90508@freenet.de...
> george_barr@yahoo.com schrieb:
>> This is regarding the DSP math/equations in general. What is "x = I +
>> jQ"? I know that j = 0 + 1i and i = sqrt(-1) and i^2 = -1. But what
>> is x = I + jQ, where x represents a form of the input data signal.
>>
>> I need this info to calc the atan(Q/I) for frequency demodulation
>> purposes. Any help is appreciated.
>>
>
> x is just a complex number. Since I and Q are real, you should have no
> problems calculating your formula.
>
> Thomas
>
What Thomas said. I is used for the In-phase component and Q for Quadrature
component. People seem to use phase = atan2(imaginary part , real part) as
a convention , if this is what you are using then phase can be interpreted
as a clockwise rotation (looking into the paper) with respect to the
In-phase direction, when you draw your Q axis at 90 degrees clockwise to the
I.
Best of Luck - Mike