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 >> >> >> >> __________________________________________________________________ >> Looking for the perfect gift? Give the gift of Flickr! >> >> http://www.flickr.com/gift/ >> >> ------------------------------------------------------------------ >> To unsubscribe from si-list: >> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field >> >> or to administer your membership from a web page, go to: >> //www.freelists.org/webpage/si-list >> >> For help: >> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field >> >> >> List technical documents are available at: >> http://www.si-list.net >> >> List archives are viewable at: >> //www.freelists.org/archives/si-list >> or at our remote archives: >> http://groups.yahoo.com/group/si-list/messages >> Old (prior to June 6, 2001) list archives are viewable at: >> http://www.qsl.net/wb6tpu >> >> >> > > > -- > 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 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu