[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] Welcome and brief update

From: Marshall White
Subject: Re: [Discuss-gnuradio] Welcome and brief update
Date: Sat, 11 Jan 2003 14:50:38 -0800 (PST)

--- Daniel Rogers wrote:
> actually, it seems that I choose 40Msps from a lack of understanding of 
> the amount of samples/Hz of radio frequency needed for correct digitization.
> That said, how is it that a 400 kHz sample rate is sufficient for a 
> 107.5 MHz FM modulated signal?  How is it that you can extract useful 
> information when you have much muhc less that one sample per cycle.
> And given all this information, what is the max frequency you could 
> demodulate at 40Msps?
> --
> Dan


The answer is that you must have a "tuner" that takes the signal at 107.5 MHz 
and "moves" it down
to a much lower frequency (called an IF, or intermediate frequency).

If you have a 40 MHz sampling rate, any IF less than 20 MHz should more or less 
be okay.

If you had a 400 kHz sampling rate, then your IF would have to be CENTERED at 
100 kHz.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]