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Topic: PN Sequences

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	Recursive Sequences
		In OEIS: - A082411 Second-order linear recurrence sequence with a(n) = a(n-1) + a(n-2).
		In OEIS: - A083216 Second-order linear recurrence sequence with a(n) = a(n-1) + a(n-2).
		In OEIS: - A083105 Second-order linear recurrence sequence with a(n) = a(n-1) + a(n-2).
	www.tanyakhovanova.com /RecursiveSequences/RecursiveSequences.html (10619 words)

	Apparatus for synchronizing linear PN sequences - Patent 4649549
		In the past, the receiver was forced to slew the clock for a linear PN sequence to line up the receiver generator with the transmitted sequence.
		For long sequences or sequences received in heavy noise (i.e., noise power density which is of the order of, or exceeds the energy per chip), such typical methods as "the sliding correlation" are impractical because of the large number of phases which must be tested with attendant dwell time required in heavy noise.
		In accordance with one important advantage, it is not necessary to slew over all the possible PN phases, because the PN synchronizer of the present invention calculates the appropriate despreading sequence regardless of the relative phase.
	www.freepatentsonline.com /4649549.html (8081 words)

	[ss] PN Sequences with a set duty cycle
		PN sequences always have odd lengths of the form 2**n - 1, so they can't have an equal number of 0's and 1's.
		It's possible to "extend" a basic PN sequence to a length that's an even power of two by stuffing a zero when the state recycles.
		I suppose you could post-process a PN sequence to change the 0/1 balance, but the process would be nonlinear and probably also have memory so it would no longer have the nice mathematical pseudo-randomness properties of all basic PN sequences.
	www.tapr.org /pipermail/ss/2006-January/000006.html (350 words)

	CDMA - Online
		A Pseudo-random Noise (PN) sequence is a sequence of binary numbers, e.g.
		The sequence appears to be random in the sense that the binary values and groups or runs of the same binary value occur in the sequence in the same proportion they would if the sequence were being generated based on a fair "coin tossing" experiment.
		The period of the PN sequence is therefore 2N-1, but IS-95 introduces an extra binary zero to achieve a period of 2N, where N equals 15.
	www.cdmaonline.com /members/workshops/terms1/1008.htm (610 words)

	VHSIC Hardware Description Language - Wikipedia, the free encyclopedia
		When simulated, it generates the Fibonacci sequence successfully, until
		When synthesized with an FPGA vendor's tools, an "Adder" module was implemented, as hoped for.
		PN Sequence Generator VHDL example see: (PN Sequences)
	en.wikipedia.org /wiki/VHDL (955 words)

	CDMA Technology
		PN sequences are periodic sequences that have a noise like behavior.
		PN sequences are therefore periodic noise like binary functions generated by a network of feedback loops, modulo-2 adders and flip-flops.
		PN sequences are used to spread the spectrum.
	www.tsp.ece.mcgill.ca /Telecom/Docs/cdma.html (1440 words)

	Amateur Spread Spectrum. Amateur project Amatorki projektWidmo rozproszone. Amatorski projekt
		Only when PN sequences in receiver and transmitter have the same phase, it is possible to despread spectrum of signal.
		When PN sequence in receiver is earlier about ½ byte than PN sequence in transmitter, we have EARLY-RSSI signal, which is used to decrease frequency of 4 MHz oscillator.
		When PN sequence in receiver is later about ½ byte than PN sequence in transmitter, we have LATE-RSSI signal, which is used to increase frequency of 4MHz oscillator.
	adamkar.republika.pl /spread_spec_rx_en.htm (2058 words)

	Apparatus and method for performing fast acquisition of PN sequences by transferring distributed samples - Patent ...
		Furthermore, because of the unrealizable fact that a carrier phase must be obtained before the acquisition completion of PN sequence since coherent demodulation is used to determine whether the value of each sequence chip is positive or negative, the state estimation technique is not suitable for practical use.
		In other words, the igniter sequence is continuously transmitted together with the main sequence to be used as a pilot sequence and that assists the receiving mobile station to accomplish the fast synchronization with the pilot sequence of the base station (ST1).
		For example, in the case of the PN sequence of period 2.sup.15 -1, the mean acquisition time of the DSA scheme according to the present invention reduces to a hundredth of that of the conventional serial search acquisition schemes.
	www.freepatentsonline.com /6389058.html (7390 words)

	A Larger Subset of Pseudo-Orthogonal Spreading Codes for WCDMA
		The principal features of these sequences are the ratio between the peak auto-correlation value and the peak cross-correlation value, as well as the average value of this ratio.
		The y sequence is combined by a logical exclusive-or operation with each row of the X matrix, which is a set of all cyclic rotations of sequence x.
		The maximum peak (of periodic and aperiodic cross-correlation) for the subset P(y,x) of 2048 different sequences is 1426; the difference relative to the auto-correlation (38,400) is 96.29%.
	www.techonline.com /community/related_content/14978?print (1178 words)

	Design of a Mechanical Analog Autocorrelator Based on PN Sequences
		Pseudonoise sequences are bit streams used in communications engineering for spread spectrum communications, radio distance measurements, and analyzing concert hall acoustics during live performances.
		We'll generalize to mod p arithmetic, leaving the binary PN sequences as a special case when p=2.
		Here is sample C code which computes values of a binary PN sequence.
	www.seanerikoconnor.freeservers.com /CommunicationTheory/PseudoNoiseSequences/MechanicalAutocorrelatorBasedOnPseudoNoiseSequences.html (674 words)

	Papers (Site not responding. Last check: 2007-10-27)
		Problems of telephonic overlap have been eliminated using Code Division in which PN sequences are mixed with digital data and transmitted.
		In fact, PN sequences are generated so that any alien code appears as random Gaussian noise, leading to security along with full usage of the spectrum.
		The sequence appears to be random in the sense that the binary values and groups or runs of the same binary value occur in the sequence in the same proportion they would if the sequence were being generated based on a Bernoulli’s fair "coin tossing" experiment.
	education.vsnl.com /vishwas/PNCDMAabstract.htm (323 words)

	IS-95A Short Code Generator (CDMA Reference Blockset)
		This block generates the I and Q short PN code sequences to be used in the quadrature spreading and despreading of CDMA signals.
		This determines the phase of the PN sequences' output.
		Integer scalar that specifies the length of the PN I and PN Q output vectors.
	www.weizmann.ac.il /matlab/toolbox/cdma/is95ashortcodegenerator.html (404 words)

	Using the Libraries (Using the Communications Blockset)
		You can use blocks in the Sequence Generators sublibrary of the Comms Sources library to generate sequences for spreading or synchronization in a communication system.
		The Kasami Sequence Generator block and the PN Sequence Generator block use this polynomial description for their Generator polynomial parameter, while the Gold Sequence Generator block uses it for the Preferred polynomial [1] and Preferred polynomial [2] parameters.
		The lower half of the preceding diagram shows how the output sequence can be shifted by a positive integer d, by delaying the output for d units of time.
	www.technion.ac.il /guides/matlab/toolbox/commblks/usersguide/tutor110.html (359 words)

	[No title]
		Various classes of PN sequences are proposed, such as the families of the Gold sequences and of the Kasami sequences, most of which are generated by LFSR (Linear Feedback Shift Registers) with good correlation behaviors for spread-spectrum communication.
		It has been demonstrated[8]~[11] that chaotic sequences are the good candidates to meet this requirement, since chaotic sequences, though they are generated by deterministic dynamical systems, have correlation properties similar to PN sequences, their screcy is much better than that of the PN sequences, and a great number of distinct sequences can be easily generated.
		Other sequences are used to modulate and mask the signal to spread the spectrum and to avoid a unfriendly detection.
	www.sss-mag.com /txt/96102.doc (1968 words)

	Using the Libraries (Using the Communications Blockset)
		Of the three types of sequences, the PN sequences are best suited for synchronization because the autocorrelation takes on just two values.
		In fact, the small set of Kasami sequences satisfy the lower bounds for correlation values, and for this reason they are also referred to as optimal sequences.
		The results show that for each block, the sequence generated by the first run is orthogonal to the sequence generated by the second run.
	www.technion.ac.il /guides/matlab/toolbox/commblks/usersguide/tutor111.html (552 words)

	The Effects of PN Sequences on the Misconvergence (ResearchIndex) (Site not responding. Last check: 2007-10-27)
		The Effects of PN Sequences on the Misconvergence (ResearchIndex)
		The Effects of PN Sequences on the Misconvergence
		The distortion of the probabilistic symmetry of the transmitted constellation can be controlled by careful selection of the underlying binary PN sequence, thereby influencing the convergence behavior of CMA.
	citeseer.ist.psu.edu /712589.html (315 words)

	Abstract (Site not responding. Last check: 2007-10-27)
		The classes of optimal PN sequences which have good pseudo-randomness and very small cross-correlation values for some range of offsets are designed by using a matrix-based approach.
		In contrast to the case of the other sequences, the optimal PN sequences produce small multiple-access interference (MAI) which is not affected by the number of users if there are sufficiently large number of users in the link.
		The new results are compared with the commonly used PN sequences to prove the superiority of our designed sequences, and the system performance of the QS-CDMA systems using different PN sequences are also evaluated.
	www.isi.ee.ethz.ch /cgi-bin/srv?isipapa:isipap/inspec-1997-1 (149 words)

	Products -- Spread-Spectrum PN Sequence Generator -- DSSS, FHSS, OQPSK, & Gold Code Capable
		The LRS-100 generates PN sequences that are useful for developing and testing both spread spectrum and conventional data communication systems.
		The LRS-205 generates PN sequences that are useful for developing and testing both spread spectrum and conventional data communication systems.
		The LRS-220 generates PN sequences that are useful for developing and testing both spread spectrum and conventional data communication systems.
	www.newwaveinstruments.com /products (789 words)

	Publications
		Generation and annotation of the DNA sequences of human chromosomes 2 and 4.
		The sequence and analysis of duplication-rich human chromosome 16.
		Ranade K, Shue WH, Hung YJ, Hsuing CA, Chiang FT, Pesich R, Hebert J, Olivier M, Chen YD, Pratt R, Olshen R, Curb D, Botstein D, Risch N, Cox DR. (2001) The glycine allele of a glycine/arginine polymorphism in the beta2-adrenergic receptor gene is associated with essential hypertension in a population of Chinese origin.
	www-shgc.stanford.edu /information/publications.html (1492 words)

	[STDS-802-16] [PREAMBLE] Complexity of GCL sequences
		Now let's analyze the complexity of GCL and PN sequences for two cases: 1) Case #1: We are acquiring initial synchronization: In this case, a time-domain correlator of length Nfft may be used.
		Some people suggested to correlate the frequency domain data with the sequence directly for PN sequences (assuming timing is obtained), which amounts to adding the results at each subcarrier after dividing the sequence.
		They may think that the autocorrelation of PN sequences can be good enough to detect the cell ID. The problem is that we have a channel with a lot frequency selectivity, so some subcarriers can be in fade relative to the other subcarriers.
	www.ieee802.org /16/arc/802-16list2/msg02028.html (682 words)

	Maximal Length Sequences
		Galois feedback generator uses only the output bit to add (in Galois field) several stages of the shift register and is desirable for high speed hardware implementation as well as software implementation.
		Shift-register sequences having the maximum possible period for an r-stage shift register are called maximal length sequences or m-sequences.
		As the cross-correlation property of these sequences is relatively poor compared to Gold codes, the same sequence with different offset are usually used for different users or for different base stations.
	rice.ecs.soton.ac.uk /bjc97r/pnseq/node2.html (301 words)

	references
		Age And Significance Of Sequence Boundaries On Jurassic And Early Cretaceous Rifted Continental Margins.
		Basement Fragments, Accreted Tectonostratigraphic Terranes And Overlap Sequences: Elements In The Tectonic Evolution Of The Arabian Shield.
		Pn, Sn, And Lg Progagation In The Middle East.
	atlas.geo.cornell.edu /ctbt/references.html (14779 words)

	Spreading Sequences
		In cellular radio communication, the autocorrelation property and the cross-correlation property of the spreading sequences are used to achieve multiple access communications, known as CDMA(Code Division Multiple Access).
		In reverse link, different users use different pseudo random sequences for their spreading and the base station recovers all the user's signals making use of the knowledge of each spreading sequences.
		As the spreading sequences generation is the first step in understanding CDMA mobile communications, I have written several well-known code generators.
	www-mobile.ecs.soton.ac.uk /bjc97r/pnseq/doc.html (203 words)

	Communications Sources :: Using the Libraries (Communications Blockset)
		The script then calculates, for each of the three blocks, the cross-correlation between the sequence generated by the first run and the sequence generated by the second run.
		This section discusses the sample time parameter, seed parameter, and signal attribute parameters that are common to many random source blocks, and then discusses each category of random source.
		The sequence is different from that produced with a different constant seed.
	www.mathworks.com /access/helpdesk/help/toolbox/commblks/ug/fp42065.html (1943 words)

	[Abstract] Parity Bit Selected PN Sequences for Improved BER Performance of Direct Sequence Spread Spectrum Systems
		Parity bits of a systematic block code are used to select the spreading sequence from a set of orthogonal pseudonoise (PN) sequences.
		At the receiver, the spreading sequence employed is determined from the outputs of the filters that are matched to each PN sequence.
		By employing parity bit selected PN sequences, the bit error rate (BER) performance of a direct sequence spread spectrum system is improved compared to a conventional spread spectrum system.
	www.actapress.com /PaperInfo.aspx?PaperID=16753 (189 words)

	Math Forum Discussions
		Yes, binary maximum-length sequences are always of odd lengths.
		>"Pseudo-Random Sequences and Arrays", by F. Jesse MacWilliams and Neil J. Sloane, Proceeding of the IEEE, Vol.
		The Math Forum is a research and educational enterprise of the Drexel School of Education.
	www.mathforum.org /kb/thread.jspa?threadID=40989&messageID=139848 (283 words)

	optim_codes_info
		Further, there also exist a need for agreed ("standardized") PN code sets to fix the codes and their initial-phases when important system parameters, such as code length and the number of simultaneous users, are decided for the purpose of numerical analysis or simulation.
		The code sets and the number of PN codes in each set are briefly summarized in Table 1.
		For the purpose of this WWW-based PN code delivery, it is important that you have received all chips correctly.
	www.ee.oulu.fi /~kk/optim_codes_info.html (1401 words)

	Advanced Spread Spectrum Topics -- PN & Gold Codes, LFSR Sequences, Multipath Fading, OQPSK/MSK/GMSK Modulation, ...
		This is an impressive summary of the many aspects of spread spectrum communication systems, starting with a brief history, and then digging right down into the details of direct sequence, frequency hopping, and time hopping.
		But a wide variety of codes are covered: Gold codes, Kasami codes, Walsh codes, multi-rate orthogonal Gold codes, Shapiro-Rudin PN codes, Sivaswamy's complementary sequence sets, and poly-phase sequences (Frank and Zadoff-Chu sequences).
		If you scroll down to Part 3 ("P3"), you will find some useful information on the generation and properties of PN codes, Gold codes, Kasami codes, Walsh codes, and Barker codes.
	www.newwaveinstruments.com /resources/sections/advanced_topics.htm (1508 words)

	Number Sequences
		Please look for Number Sequences, Number Patterns Sequences and Solve Number Sequence to find more Number Sequences information.
		Beginning June 26, 40 science teachers from Chicago Public Schools will learn to infuse awe into “awful” science subjects like chemistry, physics and biology that too often leave students uninspired.
		Identify a sequence by entering few terms in the sequence.
	www.numbersequences.info (218 words)

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