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The following will be discussed in this chapter: Defining public relations, a short history of public relations, public relations in the digital age, organization of the public relations industry, departments and staff, the public relations program, economics. | DIGITAL COMMUNICATION SUSTEMS 6.02 Fall 2012 Lecture 14 Spectral content via the DTFT 6.02 Fall 2012 Lecture 14 Slide 1 Dem o Deconvolving Output of Channel with Echo x n Channel y n Receiver z n h1 . filter h2 . Suppose channel is LTI with h1 n ồ n 0.8S n-1 H1 Q So 2 h m ejQm m 1 0.8e-jQ 1 0.8cos Q - j0.8sin Q H1 Q 1.64 1.6cos Q 1 2 EVEN junction of Q H1 Q arctan - 0.8sin Q 1 0.8cos Q ODD. 6.02 Fall 2012 Lecture 14 Slide 2 A Frequency-Domain view of Deconvolution x n Channel y n Receiver z n H1 Q filter H2 Q Noise w n Given H1 Q what should H2 Q be to get z n x n I H2 Q 1 H1 Q Inverse filter 1 H1 Q . exp -j Hi Q Inverse filter at receiver does very badly in the presence of noise that adds to y n filter has high gain for noise precisely at frequencies where channel gain H1 Q is low and channel output is weak 6.02 Fall 2012 Lecture 14 Slide
