Looks the nyquist condition cannot be satised and isi

This preview shows page 1. Sign up to view the full content.

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Ü´Øµ. The Nyquist condition in (4.6) is equivalent to the condition ÜÆ ´Øµ Æ ´Øµ or Æ ´ µ ½ in frequency domain. Now, by employing (4.8), we get ½ Ò Ò Ì ½ This is the equivalent Nyquist condition in frequency domain. It says that the folded spectrum of Ü´Øµ has to be ﬂat for not having ISI. ´ µ ¼ for When the channel is bandlimited to Ï Hz, i.e., Ï , the Nyquist condition has the following implications: ¯ ¾Ï . Then, the folded spectrum È½ ½ ´ Ò There are gaps between copies of ´ µ. No matter how ½ Suppose that the symbol rate is so high that Ì Ò Ì µ looks like the one in Figure 4.3. ´ µ looks, the Nyquist condition cannot be satisﬁed and ISI is inevitable. ¯ ½ Suppose that the symbol rate is slower so that Ì È their neighbors. The folded spectrum ½ ½ ´ Ò ´µ ¾Ï . Then, copies of ´ µ can just touch Ò Ì µ is ﬂat if and only if Ì for Ï ¼ for otherwise (4.10) The corresponding time domain function is the sinc pulse Ü´Øµ sinc´ 4.5 Ø...
View Full Document

This note was uploaded on 12/13/2012 for the course EEL 6535 taught by Professor Shea during the Spring '08 term at University of Florida.

Ask a homework question - tutors are online