What are spread spectrum techniques?
In telecommunication and radio communication, 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.
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 modulation spectrum?
We thus have developed such a theory from an engineering perspective and, using terminology from speech research, call the key result of this theory the “modulation spectrum.” A modulation spectrum decomposes a signal into a two-dimensional representation of standard frequency versus frequency of the dynamics.
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.
What is spread spectrum Technology explain the two types of it?
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 interference limited?
Which technique is interference limited? Explanation: CDMA technique capacity is interference limited.
What is side frequency?
(in radio engineering), the frequencies of oscillations that appear along with the principal (carrier) frequency ω when the oscillations are modulated. They differ from the carrier frequency by a value that is either equal to or a multiple of the frequency of the modulating signal Ω.
What is divided in FDM multiplexing technique?
In telecommunications, frequency-division multiplexing (FDM) is a technique by which the total bandwidth available in a communication medium is divided into a series of non-overlapping frequency bands, each of which is used to carry a separate signal.
Why spread spectrum is required?
The main advantage of spread spectrum communication technique is to prevent “interference” whether it is intentional or unintentional. The signals modulated with these techniques are hard to interfere and cannot be jammed. These spread spectrum signals transmit at low power density and has a wide spread of signals.
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 do you mean by spread spectrum modulation?
Spread Spectrum Modulation. A collective class of signaling techniques are employed before transmitting a signal to provide a secure communication, known as the Spread Spectrum Modulation.
How is the spectrum divided in BOC modulation?
Following this sub-carrier multiplication, the spectrum of the signal is divided into two parts, therefore BOC modulation is also known as a split-spectrum modulation.
What are the features of the spread spectrum?
Spread of energy is low and concentrated. Though the features are good, these signals are prone to interference. The spread spectrum signals have the signal strength distributed as shown in the following frequency spectrum figure. Band of signals occupy a wide range of frequencies.
Why are spread spectrum techniques called multiple access techniques?
Since multiple users can share the same spread spectrum bandwidth without interfering with one another, these can be called as multiple access techniques. Spread spectrum multiple access techniques uses signals which have a transmission bandwidth of a magnitude greater than the minimum required RF bandwidth. These are of two types.
