A transmitter is a device that sends radio frequency signals to a receiver.
A receiver is a device that receives radio frequency signals sent by a transmitter.
For example, a receiver can be at your monitor or recorder receiving video image signals from your camera.
Analog wireless is the transmission of audio and video signals using radio frequencies. Analog wireless has a transmission range from 400 feet to 2 miles in open space; however, walls, doors, and furniture will reduce this range.
Analog wireless is available to the public in three frequencies: 900MHz, 2.4GHz, and 5.8GHz. The majority of wireless security devices operate on the 2.4GHz frequency. Most household routers, cordless phones, and microwaves operate on the 2.4GHz frequency and may cause interference.
Interference is most common when two analog wireless devices compete for same frequency. Examples of analog wireless interference can be in the form of strong static interference, large horizontal lines on the video screen rolling upward, an increased noise level, or wobbly video.
Digital wireless is the transmission of audio and video analog signals encoded as digital packets over high bandwidth radio frequencies.
Digital wireless features FHSS technology (Frequency Hopping Spread Spectrum). FHSS uses a channel hopping sequence based on an algorithm generated by the receiver. As a result, the digital wireless signal is highly secure and resistant to jamming and interference.
The 2.4GHz (2.400-2.480GHz) band is divided into sections or paths of 2MHz per section, and each second, the transmission signal hops hundreds of times in a specified sequence within this frequency range. The overall bandwidth required for frequency hopping is much wider than 2MHz; however, because transmission occurs only on a small section of this bandwidth at any given time, the signal being transmitted does not suffer from greatly reduced signal degradation and also avoids paths blocked by other devices that act as sources of competing signals. The strength of the signal being transmitted is set to be from 13.5-16dBm, which is much higher than the analog transmission signal allowed by authorities around the globe.