Edimax Technology EW-7711UMN manual What is DSSS? What is FHSS? And what are their differences?

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11.What is DSSS? What is FHSS? And what are their differences?

Frequency-hopping spread-spectrum (FHSS) uses a narrowband carrier that changes frequency in a pattern that is known to both transmitter and receiver. Properly synchronized, the net effect is to maintain a single logical channel. To an unintended receiver, FHSS appears to be short-duration impulse noise. Direct-sequence spread-spectrum (DSSS) generates a redundant bit pattern for each bit to be transmitted. This bit pattern is called a chip (or chipping code). The longer the chip is, the greater the probability that the original data can be recovered. Even if one or more bits in the chip are damaged during transmission, statistical techniques embedded in the radio can recover the original data without-the need for retransmission. To an unintended receiver, DSSS appears as low power wideband noise and is rejected (ignored) by most narrowband receivers.

12. What is Spread Spectrum?

Spread Spectrum technology is a wideband radio frequency technique developed by the military for use in reliable, secure, mission-critical communication systems. It is designed to trade off bandwidth efficiency for reliability, integrity, and security. In other words, more bandwidth is consumed than in the case of narrowband transmission, but the trade off produces a signal that is, in effect, louder and thus easier to detect, provided that the receiver knows the parameters of the spread-spectrum signal being broadcast. If a receiver is not tuned to the right frequency, a spread –spectrum signal looks like background noise. There are two main alternatives, Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS).

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Contents Page Page T a L O G Chapter IV Appendix………………………………………………………………62 Main Features Introduction and safety informationSafety Information Chapter I Product InformationSystem Requirements Package ContentsDescription Familiar with your new wireless network cardNetwork Card Installation Chapter II Driver Installation and ConfigurationUnder Windows XP Under Windows Vista Page Page Page Here Page Connect to Wireless Access Point Using Edimax Utility Page Scan for Other Wireless Devices AB C DE Page Item Name Description Connect to an Access Point Page Page Page Add an Access Point to Profile Here are descriptions of every setup item Item Name Description WPA Select 802.1x EAP method from dropdown menu. Please ask ‘Remove’ Using Windows Zero Configuration Page Page Page Profile Management Add a profile Edit an existing profile Delete an existing profile Activate a profile Advanced Settings Here are descriptions of every setup item View Network Statistics WMM Setting Check this box to enable WMM function. Please click ‘Apply’ WPS Configuration WPS Button Push-Button WPS Setup PBC Push-Button ConfigurationPage Page WPS Setup PIN Page Radio On/Off About On-line Help Chapter III Soft-AP Function Switch to AP Mode and Basic ConfigurationPage Please input the Ssid the name used to identify Be operated. Selection of other channels is not Are in different country. For example whenPermitted under FCC regulations Security Setting Please select a wireless authentication type you wish to use Access Control Select the policy type of your access rule AID Connection TableEvent Log Statistics Chapter IV Appendix Specification Troubleshooting List What is the Ieee 802.11b standard? What is the Ieee 802.11g standard?Glossary What is Ad-hoc? What does Ieee 802.11 feature support?What is Infrastructure? What is BSS ID?What is AES? What is TKIP?Can Wireless products support printer sharing? What is Spread Spectrum? What is DSSS? What is FHSS? And what are their differences?What is WMM? What is WMM Power Save?What is WPS? What is STBC?What is GI? 4FCC and CE Compliance Statements Federal Communication Commission Interference StatementPage TTE Compliance Statement