What are the spread spectrum techniques?

There are two predominant techniques to spread the spectrum: 1) Frequency hoping (FH), which makes the narrow band signal jump in random narrow bands within a larger bandwidth. 2) Direct sequence (DS) which introduces rapid phase transition to the data to make it larger in bandwidth.

Which technique is most popular for spread spectrum?

Direct or Hopping Direct sequence and frequency hopping are the most commonly used methods for the spread spectrum technology.

What is FHSS technology?

FHSS is a wireless technology that spreads signals over rapidly changing frequencies. Each available frequency band is divided into subfrequencies, and signals rapidly change, or “hop,” among these subfrequency bands in a pre-determined order.

What is spread spectrum explain it with a diagram?

Spread Spectrum refers to a system originally developed for military applications, to provide secure communications by spreading the signal over a large frequency band. Figure 1 represents a narrow band signal in the frequency domain. These narrowband signals are easily jammed by any other signal in the same band.

How does direct sequence spread spectrum work?

Direct sequence spread spectrum (DSSS) is a transmission technology used in local area wireless network transmissions. In this technology, a data signal at the sending station is combined with a high data rate bit sequence, which divides user data based on a spreading ratio.

What is the direct sequence spread spectrum concept?

Direct-Sequence Spread Spectrum: A transmission technology used in WLAN (wireless LAN) 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.

What is a PN sequence spreading code?

A pseudo-noise code (PN code) or pseudo-random-noise code (PRN code) is one that has a spectrum similar to a random sequence of bits but is deterministically generated. The most commonly used sequences in direct-sequence spread spectrum systems are maximal length sequences, Gold codes, Kasami codes, and Barker codes.

What is frequency hopping method?

Frequency-hopping spread spectrum (FHSS) is a method of transmitting radio signals by rapidly changing the carrier frequency among many distinct frequencies occupying a large spectral band. The changes are controlled by a code known to both transmitter and receiver.

What do you mean by frequency hopping spread spectrum?

Frequency Hopping Spread Spectrum: A transmission technology in which the data signal is modulated by a narrowband carrier signal which changes frequency (“hops”) over a wide band of frequencies. The hopping seems random but is prescribed by an algorithm known to the receiving system. Synonyms.

Is frequency hopping spread spectrum?

Frequency-hopping spread spectrum (FHSS) transmission is the repeated switching of the carrier frequency during radio transmission to reduce interference and avoid interception.

What is spread spectrum technology?

Spread Spectrum Spread-spectrum (SS) technology uses a sequential noise-like signal to spread the normally narrowband information signal over a relatively wide band of radio frequencies. The receiver correlates the received signals to retrieve the original information signal.

What is frequency hopping spread spectrum (FHSS)?

e Frequency-hopping spread spectrum (FHSS) is a method of transmitting radio signals by rapidly changing the carrier frequency among many distinct frequencies occupying a large spectral band. The changes are controlled by a code known to both transmitter and receiver.

What is direct sequence spread spectrum (DSSS)?

In direct sequence spread spectrum (DSSS), the transmitter and receiver contain identical psuedo-random sequence generators producing a pseudo-noise (PN) signal. In the transmitter, the input data stream is XORed with the PN signal before transmission.

Does FHSS interfere with direct sequence spread spectrum?

FHSS can, however, cause interference with adjacent direct-sequence spread spectrum (DSSS) systems. Adaptive frequency-hopping spread spectrum (AFH), a specific type of FHSS, is used in Bluetooth wireless data transfer.