Contents
What are the spread spectrum techniques?
Spread-Spectrum techniques are methods by which a signal (e.g. an electrical, electromagnetic, or acoustic signal) generated with a particular bandwidth is deliberately spread in the frequency domain, resulting in a signal with a wider bandwidth.
What is spread spectrum in data communication?
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.
What do you mean by spread spectrum technique?
Definition(s): Telecommunications techniques in which a signal is transmitted in a bandwidth considerably greater than the frequency content of the original information. Frequency hopping, direct sequence spreading, time scrambling, and combinations of these techniques are forms of spread spectrum.
What are the applications of spread spectrum modulation?
Spread spectrum communication systems are widely used today in a variety of applications for different purposes such as access of same radio spectrum by multiple users (multiple access), anti-jamming capability (so that signal transmission can not be interrupted or blocked by spurious transmission from enemy).
What are the two types of spread spectrum techniques?
2.2 SPREAD SPECTRUM TECHNOLOGIES There are two main types of spread spectrum techniques that are employed. These are Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS).
Which technique is most popular for spread spectrum?
Frequency-Hopping Spread Spectrum
Frequency-Hopping Spread Spectrum (FHSS) The latter method, the most common, allows several consecutive data bits to modulate the same frequency. FFHSS is characterized by several hops within each data bit. The transmitted spectrum of a frequency-hopping signal is quite different from that of a direct-sequence system.
What is spread spectrum explain through example?
Spread spectrum is a form of wireless communications in which the frequency of the transmitted signal is deliberately varied. When you listen to a signal at 103.1 MHz on an FM stereo receiver, for example, the signal stays at 103.1 MHz. It does not go up to 105.1 MHz or down to 99.1 MHz.
How many types of spread spectrum techniques are used in CDMA?
The DS-CDMA system uses two types of spreading sequences, i.e., PN sequences and orthogonal codes. As mentioned above, the PN sequenc is generated by the pseudo-random noise generator.
What is spread spectrum & Types?
There are four generic types of spread spectrum signals: Direct Sequence (DS) – The carrier of a DS source stays at a fixed frequency. Narrowband information is spread out into a much larger bandwidth using a pseudo-random chip sequence. Pseudo noise (PN) Frequency Hopping (FHA)
What is spread spectrum What are the types of spread spectrum?
There are two main types of spread spectrum techniques that are employed. These are Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS).
Which data is transmitted using spread spectrum?
Hence, these techniques are used for military purposes. These spread spectrum signals transmit at low power density and has a wide spread of signals….Comparison between FHSS and DSSS/CDMA.
| FHSS | DSSS / CDMA |
|---|---|
| Multiple frequencies are used | Single frequency is used |
What are the disadvantages of spread spectrum?
Disadvantages: It is need complex frequency synthesizers. Not useful for range and range rate measurements. It requires error correction.
What is FHSS modulation?
FHSS is a Spread Spectrum modulation technique in which the data signal is hopped from one frequency to the other frequency after a specific interval of time, by making the signal resistant to noise, diffusion, multipath distortion, jamming and interception and makes an efficient use of frequency channels.
What is the spread spectrum?
Spread spectrum. In telecommunications, spread spectrum is a technique in which a signal’s original bandwidth is spread across frequencies, widening its bandwidth. This process can result in increased security of communications, a resistance to interference and jamming, and an LPI (low probability of interception) by unintended recipients.
What does spread spectrum communication mean?
Spread spectrum is a form of wireless communications in which the frequency of the transmitted signal is deliberately varied . This results in a much greater bandwidth than the signal would have if its frequency were not varied.