Re: [Discuss-gnuradio] USB2 <-> fast ADC & DAC

[Joseph DiVerdi]

At 3:07 AM +0100 5/30/2003, Henrique Miranda wrote:
>Joseph,     
>
>After some calculations I came with the following procedure:
>
>1: The Nyquist region can be obtained using n = floor(fc/B + 1/2)
>   where floor(x) rounds x towards minus infinity, fc is the
>   IF center frequency and B the signal bandwidth.
>
>2: The minimum fs can then be easily obtained by fs = (2*fc+B)/n
>                                                      
>3: If the optimum fs is intended use fs = 4*fc/(2*n-1) instead.
>
>Moreover, if (fc/B + 1/2) is an integer, then minimum fs equals
>the optimum fs.
>
>If you find some inconsistency in this procedure please let me know.
>Henrique

Dear Henrique,

No inconsistencies found. I had to brush up on my algebra of inequalities 
(aarghh!) but I agree with your equations #1 & #2. Nicely done and thank you 
again.

However, I must admit that I still don't fully appreciate what qualities make a 
particular fs "optimum".

Best regards,
Joseph
-- 
Joseph A. DiVerdi, Ph.D., M.B.A.          
http://xtrsystems.com/           970.980.5868 (voice) 
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