[SI-LIST] Re: what's de-emphasis

This looked to be pretty useful as well. It was hidden
in a directory. The  ole I will put this in such an obvious
place that when looking for it I am just as likely to never
find it ever again.........;-)
As Chris Knight would say "I filed this under H for toy"

http://www.altera.com/literature/wp/wp_pre-emphasis.pdf

On Fri, Oct 30, 2009 at 3:25 PM, Michael Greim <mgreim001@xxxxxxxxx> wrote:

> If you google with a little more gusto you will get what you
> want.
>
> In short, pre-emphasis modifies a waveform such that the
> interconnect distortion is effectively canceled out.  In short, and in an
> ideal
> world, the signal at the receiver looks remarkably like what
> was presented at the front of the pre-emphasis circuit.
>
> Then there's
> http://www.the-signal-and-power-integrity-institute.com/Pre-emphasis2.pdf
>
>
> Here is what wikipedia says when you google with gusto.
>
> In high speed digital transmission, pre-emphasis is used to improve signal
> quality <http://en.wikipedia.org/wiki/Signal_integrity> at the output of a
> data transmission <http://en.wikipedia.org/wiki/Data_transmission>. In
> transmitting signals at high data rates, the transmission medium may
> introduce distortions, so pre-emphasis is used to distort the transmitted
> signal to correct for this distortion. When done properly this produces a
> received signal which more closely resembles the original or desired signal,
> allowing the use of higher frequencies or producing fewer bit errors.
>
>   On Fri, Oct 30, 2009 at 3:09 PM, Adiu <adiu_panli@xxxxxxxxx> wrote:
>
>> Hello, Everyone
>>
>> What's pre-emphasis and de-emphasis?
>> I can get the following definitions from Google:
>>
>> Pre-emphasis: " Improving the signal to noise ratio by increasing the
>> magnitude of higher frequency signals with respect to lower frequency
>> signals"
>> De-emphasis: " Improving the signal to noise ratio by decreasing the
>> magnitude of higher frequency signals with respect to lower frequency
>> signals"
>>
>> There is not problem to understand the above definitions. However, I have
>> difficulities in the following concerns:
>> 1. is pre-emphasis always at the transmitter?
>> 2. is de-emphasis always at the receiver?
>> 3. what's difference between de-emphasis and equalization?
>> 4. I have not problems to draw the pre-emphasis pulse waveforms with
>> respect to a normal waveform. However, I am not quite sure of the
>> de-emphasis pulse waveforms. The attached figure shows a simple example.
>> Could someone confirms for me if the waveforms are draw correctly?
>>
>> any comments are appreciated.
>>
>> best regards,
>> adiu
>>
>>
>>
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>
>
> --
> Best Regards,
>
> Michael C. Greim
>
> And all this science they don't understand
> Is just my job six days a week.....
>
> We will either find a way or make one   -Hannibal
>
> In the middle of every difficulty lies opportunity   -Al Einstein
>



-- 
Best Regards,

Michael C. Greim

And all this science they don't understand
Is just my job six days a week.....

We will either find a way or make one   -Hannibal

In the middle of every difficulty lies opportunity   -Al Einstein


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