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`Petitioner's Exhibit 1012
`
`Page 001
`
`Petitioner's Exhibit 1012
`Page 001
`
`

`

`Transceiver and System
`Design for Digital
`Communications
`
`Scott R. Bullock, P.E.
`
`Second Edition
`
`~~ , ... / ... ; '··-;:'i,
`·f......('}~'.·~
`NOBLE
`
`PU8~ 1 SHI N G
`
`Noble Publishing Corporation
`Atlanta, GA
`
`Petitioner's Exhibit 1012
`Page 002
`
`

`

`Library of Congress Cataloging-in-Publication Data
`
`Bullock, Scott R., 1950-
`[Tranr,ceiver system design for digital communications)
`Transceiver and system design for digital communkations / ScottR. Bullock..-2nd. ed.
`p.cm.
`Originally pub.: Atlanta : Noble Pub. : under title: Transceiver system design for digital
`communications, cl995.
`Includes bibliographical references and index.
`ISBN 1-884932-14-2
`1. Radio--Transmitter-receivers--Design and construction. 2. Spread spectrum
`communications. 3. Digital oommunications. I. Title.
`
`TK6561 .B835 2000
`621.384'131--dc21
`
`~~~&
`1.;.; \:~
`-/ .. ! ''}.Jt\
`NOBLE
`
`PUB Ll$H INO
`
`00-045596
`
`Copyright 1995, 2000 by Noble Publishing Corporation.
`First edition 1995.
`
`All rights reserved. No part of tbis book may be repoduced in any form or by any
`means without prior written permission of thto publisher.
`
`Printed in the United States of America
`
`ISBN 1-884932-06-1
`
`Petitioner's Exhibit 1012
`Page 003
`
`

`

`36 I TRANSCEIVER AND SYSTEM DESIGN FOR DIGITAL COMMUNICATIONS
`
`reflected back to the source and not delivered to the load or antenna. The
`standing wave is minimized by making the impedances equal so that there
`are virtually no reflections (VSW'R 1:1).
`
`2.7 Spread Spectrum Transmitter
`
`Many systems today use spread spectrum techniques to transport data
`from the transmitter t-0 the receiver. One of the most common forms of spread
`spectrum uses phase shift keying and is refcned to as direct sequence (DS).
`The data is usually exclusive-or'd with a pseudo-random or pseudo-noise (PN)
`code that has a much higher chipping rate than the data rate. This produces
`a wider occupied spectrum in the frequency domain (spread spectrum).
`DS systems use phase shift generators (PSG) to transfer data (plus code
`for spread spectrum systems) by phase-shifting a carrier frequency. There
`are several ways to build a PSG depending on the waveform selected.
`Detailed description of phase shift keying modulation is provided. Other
`forms of spread spectrum including frequency hopping, time hopping,
`chirped FM, and ways to manage multiple users are included.
`
`Pha8e Shift Keying
`Phase shift keying (PSK) is a type of modulation where the phase of the
`can-ier is shifted to different phase states by discrete steps using a digital
`sequence. This digital sequence can be either the digitized data or a combina(cid:173)
`tion of digitized data and a spread spev'trum sequence. There are many differ(cid:173)
`ent levels and types of PSK. This discussion will be limited to a maximum of
`four phase states. However, the principle can be extended to higher order PSK
`
`Binary Phase Shift Keying (BPSK)
`The basic PSK is the binary-PSK or BPSK (see Figure 2-2). This is
`defined as shifting the carrier O or 180 degrees in phase depending on the
`digital waveform. For example, a + 1 gives O degrees phase of the carrier,
`and -1 shift.s the carrier by 180 degrees. To produce the digital waveform,
`the data or information signal is digitized, encoded, and sent out in a seri(cid:173)
`al bit stream, (if not already), and modulo 2 (exclusive-or) added to a PN
`sequence. The end result is a serial modulating digital waveform. The out(cid:173)
`put of the modulo 2 adder (exclusive-or) contains O and 1 and needs to be
`changed to ± 1 for the mixer t:o operate. However, certain forms of hard(cid:173)
`ware can bypass this step and modulate the mixer directly. Emitter-<.YJupl.ed
`logic (ECL) contains differential outputs and can be connected directly to
`the mixer. ECL is also capable of driving 50 ohms directly without an addi(cid:173)
`tional driver. A dual input mixer is required in order for the ECL logic to
`connect direct\y.
`
`Petitioner's Exhibit 1012
`Page 004
`
`

`

`THE TRANSMITTER | 37
`
`
`
`Figure 2-2 BPSK generator:
`
`Applying minus voltage to the mixer reverses the current through the
`haion of the mixer and causes the current to flow in the opposite direction
`to create a net 180 degree phase shift of the carrier. Therefore, the carrier
`is phase- shifted between 0 and 180 degrees depending on the input wave-
`form. A simple way of generating BPSK is shown in Figure 2-2. The L0 is
`either multiplied by a +1 or a —1 from the digital sequence producing a 0
`or a 180 phase shift.
`Other devices such as phase modulators or phase shifters can create
`the some waveform just as long as one digital level compared to the other
`digital level creates a 180 degrees phase difference in the carrier output,
`
`Difiiarenfial Phase Shift Keying (DPSK)
`The BPSK waveform above can be sent out as absolute phase, i.e., a 0
`degree phase shiit is a “l,” and a 180 degree phase shill: is a “0." Another way
`to perform this function is to use differential PSK (DPSK). which monitors
`the change of phase. A change of phase then (0 to 180 or 180 to 0) represents
`a “1” and no change (0 to {l or 180 to 130} represents a “0." This scheme is
`easier to detect because only the ehsnge of phase needs to he monitomd. The
`EhBOthe phase does not need to be determined. Ditferential mode can be
`applied to various phase shifting schemes and higher order phase shift
`schemes. Ihfi'erentisl results in about one dB of degradation compared to
`coherent PSK It is, however, dependent on the SIN level and the operating
`position on the probability of error curve. Note that diflerential can be
`applied in higher order PSK systems, such as differential quaternary phase
`shifl keying {DQPSK} and differential eight phase shifi keying (DBPSKl.
`
`Quaternary Phase Shifl Keying (QPSK)
`The L0 is quadrature phese-shified so that four phasors are produced
`on the outputs of the two mixers, 0 or 180 degrees out of one mixer and 90
`or 270 degrees out of the second mixer. The phasor diagram shows the four
`phssors (see Figure 2-3]. The two BPSK systems are summed together,
`which gives Four possible resultant phasors, 45, 135, 225, or 315 degrees, oil
`are in quadrature, as shown in Figure 2-3.
`
`
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`Petitioner's Exhibit 1012
`
`Page 005
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`Petitioner's Exhibit 1012
`Page 005
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`