"Direct Sequence Spread Spectrum (DSSS)
DSSS multiplies the data bits by a very fast pseudo-random bit pattern (PN sequence) that "spreads" the data into a large coded stream that takes the full bandwidth of the channel. DSSS is the basis for CDMA cellphones and 802.11 Wi-Fi wireless transmission. For a technical example of DSSS technology, see cdma.
Frequency Hopping Spread Spectrum (FHSS)
FHSS continuously changes the center frequency of a conventional carrier several times per second according to a pseudo-random set of channels, while chirp spread spectrum changes the carrier frequency. Because a fixed frequency is not used, illegal monitoring of spread spectrum signals is extremely difficult, if not downright impossible depending on the particular method. FHSS is the transmission technology in Bluetooth. See integrated-business-systems-and-services-inc, wifiand bluetooth."
From spread-spectrum
Direct-Sequencing Spread Spectrum
a. Direct sequence spread spectrum (DSSS). b. Frequency hopping spread spectrum (FHSS). c. Infrared d. Orthogonal frequency division multiplexing(OFDM)
"Direct Sequence Spread Spectrum (DSSS)DSSS multiplies the data bits by a very fast pseudo-random bit pattern (PN sequence) that "spreads" the data into a large coded stream that takes the full bandwidth of the channel. DSSS is the basis for CDMA cellphones and 802.11 Wi-Fi wireless transmission. For a technical example of DSSS technology, see cdma.Frequency Hopping Spread Spectrum (FHSS)FHSS continuously changes the center frequency of a conventional carrier several times per second according to a pseudo-random set of channels, while chirp spread spectrum changes the carrier frequency. Because a fixed frequency is not used, illegal monitoring of spread spectrum signals is extremely difficult, if not downright impossible depending on the particular method. FHSS is the transmission technology in Bluetooth. See integrated-business-systems-and-services-inc, wifiand bluetooth."From spread-spectrum
Direct Sequence Spread Spectrum It's one of the many protocols for transmitting data over a wire (or other medium)
It can't, Prof. Schiller is wrong In contrary DSSS is more vulnerable to multipathing than e.g. FHSS is since it could just ignore its own shadows after jumping.
FHSS- Which has been dropped recently DSSS- which is still used by access points to advertise themselves
22 MHz Each channel is a contiguous band of frequencies 22 MHz wide
Roald Dahl uses the word "cognoscenti" to refer to knowledgeable experts in his writing.
A maximum of three co-located direct sequence system are possible because channels 1, 6, and 11 are the only theoretically nonoverlapping channels.
DSSs include knowledge-based systems. A properly designed DSS is an interactive software-based system intended to help decision makers compile useful information from a combination of raw data, documents, and personal knowledge, or business models to identify and solve problems and make decisions.
TPS (Transaction Processing System) is used to process routine transactions such as recording sales or updating inventory in real-time. DSS (Decision Support System) is used to analyze data and provide information to support decision-making by managers. While TPS focuses on operational efficiency, DSS focuses on enhancing managerial effectiveness.
There are many data communication technologies that use low power radio waves to transmit data, including:* CDMA (used in most cell phones)* FM (used in Family Radio Service walkie talkie)* frequency-hopping spread spectrum (FHSS) (used in Bluetooth)* direct-sequence spread spectrum (DSSS), used in IEEE 802.15.4, which in turn is used by ZigBee, MiWi, 6LoWPAN, etc.* amateur radio operators often try "QRP" operation (very low power) with many different communication technologies: CW (Morse code), AM audio, FM audio, PSK31 and Hellschreiber digital text chat, and etc.