Unformatted text preview: µ and ÀÊ ´ µ are LTI ﬁlters, they can be combined and represented by an equivalent digital
½ . The
LTI ﬁlter. Denote its transfer function by À ´Þ µ and its impulse response by ½
result is the discrete time-linear ﬁlter model shown in Figure 4.11, in which the output sequence Á ¼ is given by
Á ·Ò (4.16) Wong & Lok: Theory of Digital Communications Ik
’ H(z) Ik 4. ISI & Equalization Equalizer Decision nk
Figure 4.11: Equivalent discrete-time communication system model with colored noise HW ( z ) EQZ Figure 4.12: Typical equalizer ¼ for some In general, ¼. Therefore, ISI is present. Notice that the noise sequence Ò consists of samples of the colored Gaussian noise (AWGN ﬁltered by ÀÊ ´ µ), and is not
white in general. ¯ Usually, the equalizer consists of two parts, namely, a noise-whitening digital ﬁlter ÀÏ ´Þ µ and
an equalizing circuit that equalizes the noise-whitened output as shown in Figure 4.12. The ÀÏ ´Þ µ is to “whiten” the noise sequence so that the noise samples are uncorrelated....
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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.
- Spring '08