Question: What Is Spread Spectrum And Its Types?

What is FHSS and DSSS?

Two popular methods for using the spread spectrum are frequency-hopping spread spectrum (FHSS) and direct-sequence spread spectrum (DSSS).

DSSS, in contrast, spreads the signal across a wider bandwidth than FHSS, creating a lower power density across the spectrum..

What is Spread Spectrum?

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

Does WIFI use spread spectrum?

Bluetooth uses Frequency Hopping Spread Spectrum (FHSS) and is allowed to hop between 79 different 1 MHz-wide channels in this band. Wi-Fi uses Direct Sequence Spread Spectrum (DSSS) instead of FHSS. Its carrier does not hop or change frequency and remains centered on one channel that is 22 MHz-wide.

Who invented spread spectrum?

Hedy LamarrHedy Lamarr (/ˈheɪdi/), born Hedwig Eva Maria Kiesler (November 9, 1914 – January 19, 2000), was an Austrian-American actress, inventor, and film producer. She was part of 30 films in an acting career spanning 28 years, and co-invented an early version of frequency-hopping spread spectrum.

What is spectrum in data communication?

Spectrum refers to the invisible radio frequencies that wireless signals travel over. … The portion used for wireless communication sits within that space and ranges from about 20 KHz to 300 GHz. Spectrum wavelengths are classified into different bands within the electromagnetic spectrum range.

What does S Fhss mean?

spectrum (FHSSFrequency-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 the demodulator used in Fhss?

The conventional frequency hopping modem implements the first step by using analog mixers to down-convert the modulated FSK signal to the intermediate frequency or baseband, and then uses an analog or a digital FSK demodulator to extract the received information.

What are the three main types of shift keying?

As with analog modulation, there are three parameters of the carrier wave to vary and therefore three basic types of shift keying:Amplitude Shift Keying (ASK)Frequency Shift Keying (FSK), and.Phase Shift Keying (PSK).

What are the advantages of spread spectrum?

Advantages of Spread SpectrumCross-talk elimination.Better output with data integrity.Reduced effect of multipath fading.Better security.Reduction in noise.Co-existence with other systems.Longer operative distances.Hard to detect.More items…

Why CDMA is called spread spectrum?

CDMA is a form of a Direct Sequence Spread Spectrum (where the transmitted data is coded at a very high frequency) communication. In spread spectrum, to send data, the signal bandwidth is much larger than necessary to support multi-user access.

What is PCIe spread spectrum?

The PCIE Spread Spectrum BIOS feature controls spread spectrum clocking of the PCI Express interconnect. When set to Down Spread, the motherboard modulates the PCI Express interconnect’s clock signal downwards by a small amount.

What is processing gain in spread spectrum?

Abstract: The processing gain of a spread-spectrum (SS) system is generally defined as the ratio between the transmission bandwidth and data bandwidth, and is a measure of its interference rejection capability.

When was spread spectrum invented?

1941Lamarr and Anthiel received a patent in 1941, but the enormous significance of their invention was not realized until decades later. It was first implemented on naval ships during the Cuban Missile Crisis and subsequently emerged in numerous military applications.

What are the two types of spread spectrum?

Out of many Spread Spectrums, this report analyses the two main spread spectrum systems which are the ‘Frequency Hopping and Direct Sequence’ and in addition an overview of the ‘Chirp Spread’ Spectrum.

What are the applications of spread spectrum?

Current applications of spread spectrum technology include wireless LANs (local area networks), bar code scanners, and microphones. This technology improves the efficiency and effectiveness of business processes, many of which are finding that wireless communications are requisite for success.

Should I disable Spread Spectrum?

Generally, frequency modulation through spread spectrum clocking should not cause any problems. … Therefore, it is recommended that you disable the MCLK Spread Spectrum feature if you are overclocking the memory bus. You will be able to achieve better overclockability, at the expense of higher EMI.

What is DSSS modulation?

In telecommunications, direct-sequence spread spectrum (DSSS) is a spread-spectrum modulation technique primarily used to reduce overall signal interference. … Each spreading-sequence bit, which is known as a chip, has a much shorter duration (larger bandwidth) than the original message bits.

Which is the application of DSSS signals?

Direct sequence spread spectrum applications CDMA cellphone technology: The DSSS technique was used to provide a multiple access scheme that was used for 3G cellophane technology. Each mobile used a different access code or spreading code and this enabled multiple users to access the base station on the same frequency.

What is PN sequence?

Theory: Pseudo-Noise (PN) sequences are commonly used to generate noise that is approximately “white”. It has applications in scrambling, cryptography, and spread-spectrum communications. It is also commonly. referred to as the Pseudo-Random Binary Sequence (PRBS). These are very widely used in communication.

What are spreading codes?

A spreading code is a pseudo-random code that has a narrow ambiguity function, unlike other narrow pulse codes. In CDMA a locally generated code runs at a much higher rate than the data to be transmitted.