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Re: [BP] Informative Channel



sugawara,

    1.  The channel itself will essentially kill the 3rd and higher
        harmonics of Nyquist.  The full 2dB should apply.

    2.  Just how much good a DFE Rx will do, recognizing signals which
        look like 5.156GHz sine waves and passing them while rejecting
        interference which looks like a 5.156GHz sine wave, i do not
        know.  I hope to learn more.

    4.  Maybe i am too optimistic about riding over dips in the
        transfer characteristic.

I plan to present some stuff in this general area at the Minneapolis
meeting, trying to come up with the correct values to use in the
interference tolerance test (72A, changing i think to 69A).  Thank
you for helping me to clarify my thinking.

                       charles


-- 
|--------------------------------------------------------------------|
|       Charles Moore
|       Agilent Technologies
|       ASIC Products Division
|       charles_moore@agilent.com
|       (970) 288-4561
|--------------------------------------------------------------------|

> Hello, Charles,
> 
> I agree your "nits" points.
> 
> 1. You are right for 4/pi (2dB) factor in a case of square wave at
>    TX output.
>    In actual case, for example there is 0.5pF stray capacitance
>    including TX output transistors, ESD protectors, etc.,
>    3rd harmonic will be -13dB referring to 5GHz sine wave, and the
>    factor between composite p-p vs sine wave is almost 1dB.
>    This is the reason why I ignored the factor previously. But I
>    agree that still 1dB difference exits.
> 
> 2. I agree that RX equalization need to boost at least 5GHz.
> 
> 4. Length of ..0101.. can be 31~32bit at PRBS31. In the case,
>    its spectra distributes approximate 250MHz width. I'm not sure
>    that it is wide enough to cover dip and peak of frequency ripple.
>    I understand 5dB is too match. please teach me how many dB is 
>    reasonable.
>    I guess 0101010 (8bit length) spreads approximate 1GHz, and ok to
>    cover dip and peak.
> 
> 
> I am still wondering BER at lower S/N case.
> 
> 
> M. Sugawara
>