Wireless Technology

In the world today, everybody is familiar with wireless communications of some type. It may be experience with the explosion of the cellular phone industry or the cordless phones that we love to use in our homes, or perhaps the "walkie talkies" we all played with as kids. Communication is no longer limited by the restrictive cables and wires of the past. Today, simple and reliable transmissions are possible via recent wireless developments using spread spectrum technology. The key in effective data transmission is to create a "virtual link" through the air such that communication between the two machines occurs as though a physical wire connects them. There are several schemes that exist to accomplish this, including spread spectrum communications.

Standard RF Technology

Standard narrow band RF was first developed to answer the need for communicating with virtual wire. Standard RF technology is used extensively in vehicle dispatch systems, police communications, and security guard handheld transmitters. This type of RF technology requires a Federal Communications Commission (FCC) license to install and operate. Standard RF is susceptible to interference and noise. Because of this susceptibility, standard RF signal quality is widely variable, making it unsuitable for applications that require accurate, robust, and secure communications.

Spread Spectrum Technology

Spread spectrum transmits the entire signal over a bandwidth that is much greater than that required for standard narrow band transmissions, thus gaining signal-to-noise (S/N) performance. Many spread spectrum radios can share the same frequency band, provided that each system uses a unique spreading code to reduce interference between the different radios. Because only a receiver with identical codes can de-spread the signal to recover the message, spread spectrum transceivers can tolerate a high level of interference, unlike conventional radios, providing a much greater increase in frequency capacity.