sampling theorem

[ravirevolt]

I need to generate a sine wave with 3GHz frequency can any one tell me ho
to sample it and produce the inphase and qadrature output ? after that
need to feed this inphase and qaudrature output to an fft using comple
numbers how to do it plz mention any resources available on them.

[Mike Yarwood]

"ravirevolt" <[email protected]> wrote in message
news:[email protected]...
>
> I need to generate a sine wave with 3GHz frequency can any one tell me how
> to sample it and produce the inphase and qadrature output ? after that i
> need to feed this inphase and qaudrature output to an fft using complex
> numbers how to do it plz mention any resources available on them.

You could define that at time t=0 at the source of your sinewave you have
I=1 and Q=0 and that at that time and thereafter I(t)=cos(2*pi*t*3e9) and
Q(t)=sin(2*pi*t*3e9) now you can work out what I and Q are for any t the
only thing you need to do is decide what delta_t you want to use for your
sampling. Once you have a reasonable number of samples defined, you might
feed them into your fft using complex_input_value_associated_with_time_t is
I(t) +jQ(t).

Best of Luck - Mike

[Jerry Avins]

ravirevolt wrote:
> I need to generate a sine wave with 3GHz frequency can any one tell me how
> to sample it and produce the inphase and qadrature output ? after that i
> need to feed this inphase and qaudrature output to an fft using complex
> numbers how to do it plz mention any resources available on them.

You aren't sampling anything; you're generating numbers. Once you have
chosen how many numbers you will use to represent one cycle, the
frequency doesn't matter. The ratio of supposed sinewave frequency and
the sampling frequency is all that matters.

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