[sdiy] Can you call the low pass filter in a frequency shifter an antialiasing filter?

[cheater cheater]

Thanks a lot for the tips guys. Highly appreciated. I really liked the
links and the topic mentions, that'll be helpful in future research..

Achim,

On Tue, Oct 5, 2010 at 19:40, ASSI <Stromeko at nexgo.de> wrote:
> On Tuesday 05 October 2010, cheater cheater wrote:
>> So is there an easy explanation of what a quadrature mixer is? I'm
>> happy for heavy maths, but heavy electronics scare me a bit ...
>
> Then it will certainly excite you to hear that "quadrature mixer" is the
> maths-light term for the more math-heavy description "mixer that works with
> analytic signals" (and for the more practically minded description "single-
> sideband mixer").  "Mixing" refers to modulation, which is a multiplication
> in the time-domain or equally a folding operation in the frequency domain.
> "Analytic signal" is a description of a signal by a superposition of complex
> exponentials instead of real-valued functions.

so basically we take two signals u(t) and v(t), find their analytic
representations u_a(t) and v_a(t), and we calculate w_a(t) =
x_a(t)*y_a(t), then we output Re(w(t)) and that's it?

Why do we need to multiply the analytical representation?

Cheers,
D.

On Tue, Oct 5, 2010 at 20:08, Donald Tillman <don at till.com> wrote:
> On Oct 4, 2010, at 11:02 PM, cheater cheater wrote:
>
>> So is there an easy explanation of what a quadrature mixer is? I'm
>> happy for heavy maths, but heavy electronics scare me a bit ...
>> I'm afraid the only things I can find arr involved radio-world descriptions.
>
> Check out the writeup of the Bode Frequency Shifter on my Moog Patent Reviews page:
>
>   http://www.till.com/articles/moog/patents.html
>
> (It's intentionally very concise and abbreviated, but it should give you everything you need.)
>
>  -- Don
>
> --
> Don Tillman
> Palo Alto, California
> don at till.com
> http://www.till.com
>
>
>
>
>