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	DSSS: Direct-Sequence Spread Spectrum (Site not responding. Last check: 2007-11-01)
		Direct-Sequence Spread Spectrum (DSSS) is used in WLAN 802.11 and 802.11b physical layer.
		It transmissions multiply a "noise" signal to the data being transmitted.
		This noise signal is a pseudorandom sequence of 1 and -1 values, at a frequency much higher than that of the original signal, thereby spreading the energy of the original signal into a much wider band.
	www.javvin.com /wireless/DSSS.html (60 words)

	[No title] (Site not responding. Last check: 2007-11-01)
		DSSS технология была разработана ранее для применения в военных радиосистемах с высокой помехозащищенностью и с низкой вероятностью радиоперехвата.
		DSSS системы имеют большую ширину излучения сигнала и используют последовательности длиной 11бит, что позволяет создавать 11 кратную избыточность сигнала, а следовательно повысить в 11 раз помехоустойчивость системы.
		DSSS системы могут работать при слабом сигнале, обеспечивая передачу данных на большие расстояния.
	www.eridan.cc /dsss.htm (146 words)

	Direct-sequence spread spectrum - Wikipedia, the free encyclopedia
		As with other spread-spectrum technologies, the transmitted signal takes up more bandwidth than the information signal that is being modulated.
		This effect is the basis for the code division multiple access (CDMA) property of DSSS, which allows multiple transmitters to share the same channel within the limits of the cross-correlation properties of their PN sequencies.
		As this description suggests, a plot of the transmitted waveform has a roughly bell-shaped envelope centered on the carrier frequency, just like a normal AM transmission, except that the added noise causes the distribution to be much wider than that of an AM transmission.
	en.wikipedia.org /wiki/DSSS (675 words)

	DSSS and FHSS - Spead Spectrum tutorials
		DSSS avoids interference by configuring the spreading function in the receiver to concentrate the desired signal but spread out and dilutes any interfering signal.
		DSSS is better at resisting noise up to a certain point.
		On the other hand, because a DSSS system is always transmitting on every frequency in the band, a nearby FHSS system may be unable to find any clear channel to hop to.
	www.arcelect.com /DSSS_FHSS-Spead_spectrum.htm (1189 words)

	Dsss (Site not responding. Last check: 2007-11-01)
		DSSS is one of two types of spread spectrum radio, the...
		DSSS (Data Security Systems Solutions Pte Ltd, http://www.dsssasia.com) is a leading data security integrator and solutions provider to many financial institutions and government bodies.
		DSSS is accomplished by spreading each bit of signal data is spread...
	80211gturbo.foraturbo.com /dsss (797 words)

	DSSS vs. FHSS narrowband interference performance issues
		The physics of DS interference rejection A key to the interference rejection of DSSS is the cyclic cancellation of the spreading code under consecutive digital multiplications, implemented by the exclusive (or gate).
		Figure 10a is the channel test setup, showing the DSSS signal at 915 MHz, which for this photograph is the x15 version, and the interferer at 935 MHz with an amplitude that is 40 dB greater than the DSSS signal.
		For the DSSS system, this sensitivity to large out-of-band interferers is a direct consequence of the switched mixer method of generating BPSK.
	rfdesign.com /mag/radio_dsss_vs_fhss (3703 words)

	Direct Sequence Spread Spectrum (DSSS) (Site not responding. Last check: 2007-11-01)
		The DSSS process is performed by effectively multiplying an RF carrier and a pseudo-noise (PN) digital signal.
		The bandwidth in DSSS systems is often taken as the null-to-null bandwidth of the main lobe of the power spectral density plot (indicated as 2Rc in Fig.
		One feature of DSSS is that QPSK may be used to increase the data rate.
	www.qsl.net /n9zia/wireless/dsss.html (412 words)

	Spread spectrum - Wikipedia, the free encyclopedia
		Originally there were two motivations: either to resist enemy efforts to jam the communications (anti-jam, or AJ), or to hide the fact that communication was even taking place, sometimes called low probability of intercept (LPI).
		Frequency hopping (FHSS), direct-sequence spread spectrum (DSSS), PN spreading (using PN Sequences), time scrambling, chirp, and combinations of these techniques are forms of spread spectrum.
		Wireless Ethernet standard IEEE 802.11 uses either FHSS or DSSS in its radio interface.
	en.wikipedia.org /wiki/Spread_spectrum (1710 words)

	CWNP Exam Terms
		For example, DSSS is specified in IEEE 802.11-1999 (R2003) clause 15 but is often simplified as "clause 15." Amendments are updates (changes) to the standard.
		OFDM is not backwards compatible with HR-DSSS or DSSS because it is used in a different frequency band and it uses a different modulation technique.
		This is a hybrid modulation combining a DSSS preamble and header with an OFDM payload transmission.
	www.cwnp.com /exams/exam_terms.html (2061 words)

	Bioterrorism Preparedness and Response: Use of Information Technologies and Decision Support Systems: Summary of ...
		However, this system is limited in that it is specific for infectious diseases; consequently, even those clinicians with access to this technology may not use it if the patient does not present with a fever or other signs or symptoms of infectious disease.
		For example, there are diagnostic DSSs currently available in hospitals with electronic medical records that provide clinicians with an estimate of the likelihood of community-acquired pneumonia or active pulmonary tuberculosis based exclusively on data collected from the medical record.
		Diagnostic DSSs have not been used widely, and several of the available systems require time-consuming manual input of patient data, which is impractical in many clinical settings.
	www.ahrq.gov /clinic/epcsums/bioitsum.htm (4991 words)

	DSSS vs. FHSS narrowband interference performance issues
		The results of this example are shown in Figure 4, which compares the DSSS system throughput factor to the interference to signal ratio (ISR).
		Notice that the occupied bandwidth of the DSSS signals of Figure 6 are not absolute.
		It is important to also check the behavior of the DSSS systems in the presence of such large, out-of-band signals.
	www.rfdesign.com /mag/radio_dsss_vs_fhss/index.html (3703 words)

	DSSS CHICKSANDS - Find Friends from DSSS CHICKSANDS at Forces Reunited
		Steven Bartlett was at DSSS Chicksands between 2001 and 2003
		Julian Bennett was at DSSS Chicksands between 1989 and 2003
		Samuel Stocker was at DSSS Chicksands between 1937 and 1946
	www.forcesreunited.org.uk /namearchive/units/HMSNames/DSSS-Chicksands.html (158 words)

	Network Computing \| Workshop \| Infrastructure \| Anatomy of IEEE 802.11b Wireless \| Page 1 \| August 7, 2000 (Site not responding. Last check: 2007-11-01)
		IEEE 802.11b data is encoded using DSSS (direct-sequence spread-spectrum) technology.
		DSSS works by taking a data stream of zeros and ones and modulating it with a second pattern, the chipping sequence.
		The PLCP consists of a 144-bit preamble that is used for synchronization to determine radio gain and to establish CCA.
	www.networkcomputing.com /1115/1115ws2.html (870 words)

	What is DSSS? - A Word Definition From the Webopedia Computer Dictionary
		DSSS is one of two types of spread spectrum radio, the other being frequency-hopping spread spectrum.
		DSSS is a transmission technology used in LAWN transmissions where a data signal at the sending station is combined with a higher data rate bit sequence, or chipping code, that divides the user data according to a spreading ratio.
		The chipping code is a redundant bit pattern for each bit that is transmitted, which increases the signal's resistance to interference.
	www.webopedia.com /TERM/D/DSSS.html (181 words)

	An Introduction to Direct-Sequence Spread-Spectrum Communications - Maxim/Dallas
		The message is thus made invisible, an effect that is particularly strong with the DSSS technique.
		DSSS and FHSS are the two techniques most in use today.
		The most difficult area is the receiver path, especially at the despreading level for DSSS, because the receiver must be able to recognize the message and synchronize with it in real time.
	www.maxim-ic.com /appnotes.cfm/appnote_number/1890 (2477 words)

	Bluetooth FHSS compared to WLAN DSSS
		Mostly the difference is in the baseband, DSSS has to run on a much more powerful DSP chip since DSSS uses chip rate (many times higher than the symbol rate) while FHSS only need to run at the symbol rate, so the power consumption for FHSS is much lower and the complexity is lower too.
		In the RF part, FHSS use FSK which is relatively easy to build and the noise immunity is better while DSSS usually use QPSK(for IEEE 802.11 2 Mbps) or CCK (in IEEE 802.11b 11Mbps) which are more complex and the noise immunity is inferior to FSK.
		However, one major disadvantage of FHSS is that it is slower than DSSS, mostly due to the fact that FSK need a frequency synthesizer (to hop frequency) and if you need a greater spread spectrum advantage, it has to be fast but this is not easy to implement.
	www.palowireless.com /infotooth/knowbase/othernetworks/57.asp (207 words)

	Looking for a 2.4Ghz DSSS OEM module.
		I can't afford an FPGA for all the filtering, pulse shaping and spreading code, so I was hoping that there are some nice little OEM modules that do it all for me, letting me worry about the protocol/data etc..
		Since DSSS is direct spreading, generally the bandwidth of these is 11-22Mhz.
		I've even thought about buying a cheap wireless network card, and ripping out the baseband IC, leaving the screened RF circuit with on-board antenna's, and all the analogue....In fact...I often use pre-built computer parts, since they're so cheap and easily available...eg: old SDRAM is cheaper than the individual chips, and you get about 5.
	www.edaboard.com /viewtopic.php?p=539390 (721 words)

	DSSS Products > Certificate Authority
		DSSS CA software is a flexible one-stop solution for secure business communications.
		It is designed to make the deployment of digital certificates transparent to end-users and easier on administrative staff by enabling them to take advantage of existing authentication systems.
		DSSS CA technology helps organizations to streamline the enrollment process and automate the registration and authentication of certificate requests as well as the approval, issuance and deployment of digital certificates.
	www.dsssasia.com /htmdocs/products/certificate_authority/c_authority_overview.htm (98 words)

	DMX Without Wires - A Comparison (mrEriksson.net)
		These two standars are Direct Sequencing Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS), where DSSS is the most common one, due to it's advantage in available bandwidth and a low price-level.
		Due to it's low price, IEEE 802.11b (DSSS) equipment could be seen as the optimal choice for DMX over wireless Ethernet, however, due to it's high sensitivity to external interferences, none of the IEEE 802.11a/b/g standards are recommended for this particular purpose.
		DSSS is the other type of Spread Spectrum radio available.
	www.mreriksson.net /miscdocs/dmx-without-wires (1447 words)

	Bioterrorism Preparedness and Response: Use of Information Technologies and Decision Support Systems
		We found 6 general diagnostic systems, 4 systems designed to improve radiologic diagnoses, 4 telemedicine systems, 4 systems for the diagnosis of infectious diseases, 1 system for the diagnosis of dermatologic lesions, 1 system for the diagnosis of community-acquired pneumonia, and 3 systems for other purposes.
		The need for clinicians to manually enter patients' signs and symptoms into diagnostic DSSs -- a laborious step that may be a barrier to the use of these systems and has been demonstrated to increase inter-user variability -- is eliminated by the few systems that automatically collect patient data from an electronic medical record.
		Because the individuals collecting and analyzing the environmental and clinical samples are often at considerable distance from public health decision makers, detection systems could benefit from the capacity for secure transmission of data to these decision makers.
	www.ncbi.nlm.nih.gov /books/bv.fcgi?rid=hstat1.chapter.78731 (6093 words)

	O'Reilly Network -- 802.11b Tips, Tricks, and Facts
		DSSS (Direct Sequence Spread Spectrum) breaks the band into 14 overlapping 22-MHz channels and uses one at a time.
		The FHSS frequency-hopping cards were the first to hit the marketplace, as they were cheaper to produce and easier to implement than DSSS.
		As time marched on (and with Moore's Law in effect), the processing power needed to cheaply implement DSSS soon became available.
	www.oreillynet.com /pub/a/wireless/2001/03/02/802.11b_facts.html (1259 words)

	cwnp.com :: View topic - DSSS Channel width
		To me, it seems that a DSSS channel is 5 MHz wide, but p.
		186 says that "Each DSSS channel is a contiguous band of frequencies based around a center frequency that uses 1 MHz carrier frequencies, just as with FHSS.".
		I recommend that CWNAv3 study guide page 186, last paragraph, first sentence read: "Each DSSS channel is a contiguous band of frequencies based around a center frequency." The reference to FHSS is a mistake.
	www.cwnp.com /phpBB2/viewtopic.php?t=941 (887 words)

	IEEE 802.11 - Internet-ional Articles v. 1 no. 1
		Direct Sequence Spread Spectrum (DSSS) is one of the modulation techniques provided for by the IEEE 802.11 and the one chosen by the 802.11 Working Group for the widely used IEEE 802.11b devices.
		DSSS modulation is governed in the United States by FCC Regulation 15.247 and in Europe by ETSI Regulations 300-328.
		DSSS in IEEE 802.11 uses Differential Binary Phase Shift Keying (DBPSK) for 1 Mbps, and Differential Quadrature Phase Shift Keying (DQPSK) for 2 Mbps.
	www.isoc.org /pubs/int/cisco-1-1.html (4193 words)

	rfid fh and dsss together (Site not responding. Last check: 2007-11-01)
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	www.frequency-identification.info /rfid-fh-and-dsss-together.htm (109 words)

	Welcome Page (Site not responding. Last check: 2007-11-01)
		The mission of the DSSS is to “consider and propose provisions for Louisiana’s comprehensive efforts to
		Act 1147 amended the Community and Family Support System Act (Act 378 of 1989) and extended the guiding principles for systems change contained in that earlier law to encompass the needs of all people with disabilities, regardless of age or type of disability.
		The planning activities of the DSSS are supported under grant CFDA 93.779 from the U.S. Department of Health and Human Services, Centers for Medicare and Medicaid Services.
	www.gov.state.la.us /disabilityaffairs/dsss/index.htm (318 words)

	Romb Networks, ISP. Wavelan. Сравнительная характеристика методов модуляции ...
		:::: Сравнительная характеристика методов модуляции DSSS и FHSS.
		Метод DSSS позволяет достигать значительно большей производительности (2 Мб/с на один канал, 6 Мб/с на весь диапазон 2,4 ГГц), а кроме того, обеспечивают большую устойчивость к узкополосным помехам (поскольку выбором поддиапазона для передачи часто удается отстроиться от помех) и большую дальность связи.
		Еще одно достоинство FHSS-устройств состоит в том, что они, в отличие от DSSS, могут сохранять работоспособность в условиях широкополосных помех, - например, создаваемых DSSS-передатчиками, но это оборачивается тем, что сами они мешают обычным узкополосным устройствам.
	romb1.dela.kr.ua /wavelan/characteristic.html (168 words)

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