What is direct sequence spread spectrum modulation?

What is direct sequence spread spectrum 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.

What happens in case of direct sequence spread spectrum?

In direct sequence spread spectrum (DSSS), the transmitter and receiver contain identical psuedo-random sequence generators producing a pseudo-noise (PN) signal. In the transmitter, the input data stream is XORed with the PN signal before transmission.

What sequences are used for spreading the spectrum?

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.

What is spread spectrum modulation technique?

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.

How many types of spread spectrum techniques are there?

There are four techniques of spread spectrum namely direct sequence spread spectrum (DSSS), frequency hopping spread spectrum (FHSS), chirp spread spectrum (CSSS) and time hopping spread spectrum (THSS). Each of these techniques is described, with a brief mention about its basic mechanism.

Which type of spread spectrum is more secure?

Direct sequence transmission gives the most robust and practical option for a digital spread spectrum. Information to be transmitted is digitally encoded using a locally generated pseudo-noise coding algorithm, which creates a local code that runs at a vastly higher frequency than that of the transmitted data.

How is the direct sequence spread spectrum used?

In telecommunications, direct-sequence spread spectrum ( DSSS) is a spread-spectrum modulation technique primarily used to reduce overall signal interference. The direct-sequence modulation makes the transmitted signal wider in bandwidth than the information bandwidth. After the despreading or removal of the direct-sequence modulation in

How does direct sequence modulation affect the bandwidth?

The direct-sequence modulation makes the transmitted signal wider in bandwidth than the information bandwidth. After the despreading or removal of the direct-sequence modulation in the receiver, the information bandwidth is restored, while the unintentional and intentional interference is substantially reduced.

Who was the first person to use direct sequence modulation?

After the despreading or removal of the direct-sequence modulation in the receiver, the information bandwidth is restored, while the unintentional and intentional interference is substantially reduced. The first known scheme for this technique was introduced by a Swiss inventor, Gustav Guanella.

Why is the spread ratio of a signal important?

The ratio of chips to data is known as the spreading ratio: the higher the ratio, the more immune to interference the signal is, because if part of the transmission is corrupted, the data can still be recovered from the remaining part of the chipping code.