theory of spread spectrum communications a tutorial pdf

... subset of R N and that Ω is a ∂-submanifold of R N of class C M with M ≥ 2. Then, t here is a bounded open subset  Ω of R N such that  Ω is a ∂-submanifold of R N of class C ∞ (even C ω ) and that ... 1.2.This was noted by Geymonat, along with the fact that Corollary 2.1 was only known to be true in special cases 3, page 242. 3. Proof of Lemma 1.3 Under the assumptions of Lemma 1.3, Ω has a finite ... 3 and it is straightforward to check that the proof of Theorem 1.2 carries over to this case if M ≥ 2. If so, Corollary 2.1 is also valid, with a similar proof and an obvious modification of...

Ngày tải lên: 21/06/2014, 20:20

... 1997. [9] S. Barbarossa and A. Scaglione, “Adaptive time-varying can- cellation of wideband interferences in spread- spectrum com- munications based on time-frequency distributions,” IEEE Transactions ... Pennsylvania, Pa, USA, Au- gust 2000. [14] M. V. Tazebay and A. N. Akansu, “Adaptive subband tr ans- forms in time-frequency excisers for DSSS communications systems,” IEEE Transactions on Signal ... RT can be applied to gray-level images, it does not encompass all possible variations of the HT. Con- sidering the advantages and disadvantages of each transform, we use the combined HRT as proposed...

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Ngày tải lên: 07/09/2013, 13:45

... spectra of the indicates that the real and are imaginary components of are uncorrelated and, hence, independent and have the same variance Since the density of a complex- valued random variable ... otherwise, and Since the real and imaginary components of are jointly Gaussian, this random process is a complex-valued Gaussian random variable. Straightforward calculations using (1-40) and the ... possible paths. At any node, only the partial path reaching that node with the largest partial metric is re- tained, for any partial path stemming from the node will add the same branch metrics to all...

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... military applications and still are. Much of the literature on military applications of spread spectrum communications is classified. A notable application of spread spectrum to civilian uses was ... includes spread spectrum modem specifications for operation at data rates of 1 and 2 Mbps, and the 802.11b standard, released in Oct. 1999, has a maximum raw data rate of 11 Mbps with both operating ... TypesofSpreadSpectrumModulation 7 4 Spreading Codes . 11 5 Code Acquisition and Tracking [1] 24 6 Performance of Spread Spectrum Systems Operating in Jamming—No Coding 50 7 Performance of Spread Spectrum...

Ngày tải lên: 27/06/2014, 09:20

... is a simple quick tutorial that I have done and others might find useful in coloured pencils of how to make eyes look realistic. Figure 1: Image reference of a pair of eyes from the “Nat ... started on the left part of the face. Step 3 : Finished piece Figure 4: The finished piece in landscape. I have added some yellow in the eye brows and used black for the darker areas and ... areas and make it look bolder. As you can see I have used two blues for the colour inside the eyes and used black. I ensured that I added layers of colour to add contrast and lightly shaded the...

Ngày tải lên: 29/06/2014, 00:20

... applications of spread spectrum communications is classified. A notable application of spread spectrum to civilian uses was to cellular radio in the 1990s with the publication of interim standard ... operation at data rates of 1 and 2 Mbps, and the 802.11b standard, released in Oct. 1999, has a maximum raw data rate of 11 Mbps with both operating in the 2.4 GHz band. Specifications 802.1 1a and 802.11g, released ... known as binary direct sequence (DS) spread spectrum modulation, because a data bit 1 (of duration T b ) is sent as the spreading code, c 1 ( t ) ,noninvertedandadatabit0(ofdurationT b ) is sent as...

Ngày tải lên: 07/08/2014, 21:20

... 13:15 FUNDAMENTALS OF SPREAD SPECTRUM MODULATION 11 4 SPREADING CODES An important component of any spread spectrum system is the pseudo-random spreading code. Many options exist for the generation ofsuch ... Block diagrams of the transmitter (a) and receiver (b) for QPSK spreading with arbitrary phase modulation [1]. 3.1 QPSK Spreading With Data Phase Modulation Modulation types other than BPSK may be ... sequence and the re- ceived frequency-hopped spread spectrum signal will be de-hopped whereupon an appropriate data demodulator can be used to recover the data sequence. In the early days of spread spectrum, FHSS...

Ngày tải lên: 07/08/2014, 21:20

... −j } , which means that the transmitted signal is spread by phase shifts that can take on the values { 0,π,π/2, −π/2 } radians. In fact, for the IEEE 802.11b standard, the CCK spreading phase values are ... several reasons. For example, four-phase spreading is used in certain spread spectrum systems by implementing two biphase systems in parallel. Use of a quaternary code would simplify such a transmitter. ... 1. For a delay of book Mobk087 August 3, 2007 13:15 FUNDAMENTALS OF SPREAD SPECTRUM MODULATION 21 TABLE 4: Worst-Case Correlation Magnitude, for the S(0) Family [10] MAXIMUM ABS. NORMALIZED rNCORRELATION...

Ngày tải lên: 07/08/2014, 21:20

... alarms. A false alarm is particularly expensive because it generally takes the synchronization mechanism significant time to attempt tracking as the result of a false alarm and then having to recover ... 6 of Fig. 14, we have all paths beginning at the trail of a new code phase to the rejection of that book Mobk087 August 3, 2007 13:15 FUNDAMENTALS OF SPREAD SPECTRUM MODULATION 25 5.1 Serial ... carrier acquisition or data demodulation because this allows the benefits of spread spectrum to be realized, in particular, resistance to interference and multipath and discrimination against other users. Also,...

Ngày tải lên: 07/08/2014, 21:20

... literature [12]. Example9. Compare serialsearch and digital matched filter acquisition under ideal conditions of P d = 1andP fa = 0, an initial code uncertainty of 10,000 half-chips, and a chip rate ... only a portion of the code duration and also because of possible data transitions during the correlation duration. In spiteof these possibledegradations, matched filtercode acquisition is attractive ... the fine code tracking and data detection. The bandpass matched filter (it could be realized at quadrature baseband) is matched to K chips of the spreading code modulating the IF carrier, so its...

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