What is the difference between direct sequence spread spectrum and frequency hopping spread spectrum?
FHSS and DSSS, which stand for Frequency Hopping Spread Spectrum and Direct Sequence Spread Spectrum, are two spread spectrum techniques. The main difference is in how they spread the data into the wider bandwidth. FHSS utilizes frequency hopping while DSSS utilizes pseudo noise to modify the phase of the signal.
What is the difference between frequency hopping and direct sequence?
FHSS vs DSSS The difference between FHSS and DSSS is their different ways of transmitting the information into a wider bandwidth. FHSS uses the process of “hopping” while DSSS connects the signals through pseudo-noise. FHSS is one of the two-spread spectrum technology, which is a form of radio transmission.
Did Hedy Lamarr invent frequency hopping?
Actress Hedy Lamarr (bottom) and composer George Antheil (top left) patented a form of frequency hopping for secure communication.
How did Hedy Lamarr frequency hopping work?
Lamarr realized that by transmitting radio signals along rapidly changing, or “hopping,” frequencies, American radio-guided weapons would be far more resilient to detection and jamming. The frequencies are “carried in waves through space like melodies,” Lamarr’s character explains.
What are the advantages of 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. An intruder with no official access is never allowed to crack them.
What is direct sequence spread spectrum technology?
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 Hedy Lamarr known for?
Hedy Lamarr was an Austrian-American actress and inventor who pioneered the technology that would one day form the basis for today’s WiFi, GPS, and Bluetooth communication systems. Lamarr was originally Hedwig Eva Kiesler, born in Vienna, Austria on November 9th, 1914 into a well-to-do Jewish family. …
Who invented hopping spread spectrum?
Hedy Lamarr
Hedy Lamarr, inventor of the Frequency Hopping Spread Spectrum.
What is frequency hopping spread spectrum technique?
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. Interference at a specific frequency will affect the signal only during a short interval.
What is the disadvantage of spread spectrum?
Involves low power spectral density since signal is spread over a large frequency band. Disadvantages: Bandwidth inefficient; • Implementation is somewhat complex. Two of the most popular techniques that provide spectrum spreading in a spread spectrum system are direct sequence and frequency hopping.
Which is more bandwidth efficient spectrum?
Explanation: Of all the modulation showed, QAM is the most bandwidth efficient one. Explanation: The primary communication resources are transmitted power and channel bandwidth. 8. Greater the redundancy lesser is the bandwidth expansion.
What is FHSS (frequency hopping spread spectrum)?
In FHSS, which stands for Frequency Hopping Spread Spectrum, RF carrier frequency is changed according to the Pseudo-random sequence (PRS or PN sequence). This PN sequence is known to both transmitter and Receiver and hence help demodulate/decode the information.
What are the technical issues in direct sequence spread spectrum (DSSS)?
There are three technical issues are particularly relevant; frequency allocation, frequency roaming, and frequency interference. In direct sequence spread spectrum (DSSS), the transmitter and receiver contain identical psuedo-random sequence generators producing a pseudo-noise (PN) signal.
What is direct sequence spread spectrum modulation?
Related topics. In telecommunications, direct-sequence spread spectrum (DSSS) is a spread spectrum modulation technique used to reduce overall signal interference. The spreading of this signal makes the resulting wideband channel more noisy, allowing for greater resistance to unintentional and intentional interference.
What is RF carrier frequency in FHSS chip?
In FHSS, which stands for Frequency Hopping Spread Spectrum, RF carrier frequency is changed according to the Pseudo-random sequence (PRS or PN sequence). This PN sequence is known to both transmitter and Receiver and hence help demodulate/decode the information. Within one chip duration, RF frequency does not vary.