Printed in the United States of America.
`Library of Congress Catalog Card No. 78-154683
`system, without written permission from the copyright owner.
`photocopying, recording, or by any informationai storage and retrieval
`or utilized in any form or by any means, electronic or mechanical, including
`No part of the material protected by this copyright notice may be reproduced
`Massachusetts. All rights reserved. Printed in the United States of America
`© Copyright 1971 by Allyn and Bacon, Inc., 470 Atlantic Avenue, Boston,
`
`BOSTON
`
`ALLYN and BACON, Inc.
`
`느
`
`◦会
`
`Syracuse University
`Norman Balabanian
`Consulting Editor
`
`The ALLYN and bacon Series
`
`in Electrical Engineering
`
`This book is part of
`
`University of Alabama
`University of Houston
`Electrical Engineering
`Professor of Electrical Engineering
`Associate Professor of
`Richard S. Simpson Ronald C. Houts
`
`Systems
`Communication
`Analog and Digital
`Fundamentals of
`
`IPR2020-00038
`MM EX1015, Page 1
`
`

`

`Figure 11-2 Density functions for envelope detection of ASK signals
`
`V
`
`Pi(r)
`
`Po(r)
`
`Pi(f)
`
`zero
`(ll.le)
`
`2N0Br°\Ñ^B
`rV
`r2+ F
`
`2-i
`
`d(f>
`
`N0B
`
`rV cos (¡)"
`
`exp +
`
`o
`
`.2n
`
`2N0b\ It
`r2 + V21 1
`
`exp
`
`exp
`
`NqB
`
`r
`
`N0B
`
`r
`
`Jo•PiO, 샀) d<t)
`
`Pi(r) = Í
`2n
`
`which gives
`We can obtain the envelope density function p^r) by integrating over <j),
`
`.(11.Id)
`
`2N0B
`
`r2 + F2 _ 2rV cos 삼■
`
`exp
`
`ItzNqB
`
`r
`
`source
`we can
`
`obtain solutions for the error performance. Assuming equal
`It will be necessary for us to determine the threshold before
`
`order. The density functions p-^r), i = 0 or 1，are shown in Fig. 11-2.
`where IQ(x) is the modified Bessel Function of the first kind and
`
`(11.1c)
`
`r(t) = [F+ x(i)] cos (a)。i) + y(t) sin (co01)
`
`in phase with the signal while the other is in phase quadrature，i.e.，
`given by the sum of (8.19f) and (11.1b). One component of the noise is
`from 0 to 2n radians. Hence, with signal present the filter output is
`where the initial phase angle 0 is a random variable uniformly distributed
`(11.1b)
`
`sx{i) = V cos (o)01 + 0)，
`
`express the incoming signal 가(¿) as
`where the noise power P in (8.19o) has been replaced by NQ B. We can
`
`(ll.la)
`
`r > 0,
`
`iVBeXP l2N0B.
`r -r2l
`
`r
`
`Po(r)
`
`data bit is a ZERO or a ONE.
`threshold-decision circuit is used to determine whether the incoming
`tion is present in the amplitude, an envelope detector followed by a
`influencing a decision regarding the next bit. Because the signal informa­
`to ignore intersymbol interference, i.e.，energy associated with one bit
`B is approximately equal to the bit rate 1 ¡Th. This assumption permits us
`tion discussed in Chapter 8. It will be assumed that the filter bandwidth
`has power N0 B and can be represented by the narrowband approxima­
`the noise outside of the filter bandwidth B. Therefore，the output noise
`narrowband filter is used to improve the incoming SNR by removing
`
`for the envelope is Rayleigh, i.e.，
`band noise. We know from Chapter 8 that the probability density function
`transmitted. With no signal present the filter output is simply narrow-
`for the received waveform given that either a ZERO or a ONE was
`We can determine the conditional probability density functions
`
`Figure 11-1 Noiicoherent ASK detector
`
`Di> Ro：m= 1
`
`DiKRfiim^O
`
`CIRCUIT
`DECISION
`
`DETECTOR
`ENVELOPE
`
`r(t)
`
`NARROWBAND
`
`FILTER
`
`The noncoherent detector for ASK signals is shown in Fig. 11-1. The
`ASK Detector
`
`can be shown (see Problem 11.1-1) to be
`lope and phase of an incoming waveform consisting of signal plus noise
`enve-
`without affecting the final results. The joint density function for
`where the Q found in (11.1b) has been arbitrarily set equal to 0 radians
`
`phase-coherent channel.
`detecting information transmitted by phase shifts without having
`coherent detection of ASK and FSK signals, plus a technique for
`assumption is not justifiable. Schemes will be presented for the
`non-
`
`a
`
`347
`
`11.1 Noncoherent Detector Techniques
`
`Digital Communication Techniques
`
`346
`
`IPR2020-00038
`MM EX1015, Page 2
`
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