Table of Contents
- 1 Why do we need spread spectrum?
- 2 How does the use of spreading codes increase signal bandwidth?
- 3 What are the spread spectrum techniques?
- 4 Which of these is the way to spread the bandwidth of signal?
- 5 How is the spread spectrum related to bandwidth?
- 6 How is the original signal recovered from the spread spectrum?
Why do we need spread spectrum?
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.
Which spread spectrum is more bandwidth efficient?
Explanation: Time hopping spread spectrum is more bandwidth efficient.
Why is spread spectrum a more secure method of using WIFI?
Spread spectrum communications are normally secure, because spread spectrum produces a pseudo-random signal, so the transmitted signal appears as noise to other receivers-only receivers possessing the proper duplicate pseudo-random noise code sequence are able to recover the signal.
How does the use of spreading codes increase signal bandwidth?
In DSSS, a spreading code is used to map each data bit in the original signal to multiple bits in the transmitted signal. Because the pseudorandom code provides a wide bandwidth to the input data, it allows the signal power to drop below the noise threshold without losing information.
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.
Where is spread spectrum used?
Spread-spectrum clock generation (SSCG) is used in some synchronous digital systems, especially those containing microprocessors, to reduce the spectral density of the electromagnetic interference (EMI) that these systems generate.
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.
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 spread spectrum and its goal?
In spread spectrum (SS), we combine signals from different sources to fit into a larger bandwidth, but our goals are to prevent eavesdropping and jamming. To achieve these goals, spread spectrum techniques add redundancy; they spread the original spectrum needed for each station.
Which of these is the way to spread the bandwidth of signal?
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 filter is used to get the final FHSS signal?
Which filter is used to get the final FHSS signal? Explanation: Band pass filter is used to block difference frequency and allow the sum frequency to yield final FHSS signal.
What is meant by spread spectrum?
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.
Direct sequence spread spectrum (DSSS) introduces rapid phase transition to the data making it larger in bandwidth. As the period T of a signal gets shorter in time (or rate R increases), the bandwidth B of the signal increases: R = 1/T = 2B (Nyquist Rate) Figure 3: Rate and period are related to bandwidth by when pulse shaping is used.
Why does a spread spectrum signal have lower peak power?
A spread-spectrum signal has lower peak power, equal total power, and wider bandwidth. In other words, the available transmission power is distributed over a wider range of frequencies. Spread-spectrum techniques make a system more robust against jamming and interference.
What is the purpose of direct sequence spread spectrum?
DSSS, direct sequence spread spectrum is a form of spread spectrum transmission which uses spreading codes to spread the signal out over a wider bandwidth then would normally be required.
How is the original signal recovered from the spread spectrum?
The original signal is recovered by multiplying the spread-spectrum signal by the same PN code. A spread-spectrum signal has lower peak power, equal total power, and wider bandwidth.