Digital audio broadcasting is the most essential development in radio technology. It is very advanced technology in the radio technology. Digital audio broadcasting is audio broadcasting in which analog audio is converted into a digital signal and broadcast on an allocated channel in the AM or FM frequency range. Digital audio broadcast signals are transmitted in-band, on-channel. Were by using this number of stations can be carried inside the same frequency range.A digital signal allows several advantages over conservative analog transmission, as well as improved sound quality, reduced desertion.

By Using the Digital audio broadcasting information, we may also be possible to see what song is coming up next. Some Digital audio broadcasting stations offer up to the minute news, sports, and weather headlines or announcement in a scrolled text format on the display. The main advantages of digital technology are it can create broadcasting space for hundreds of new channels and then the higher description signals can deliver CD-quality sound.

Signal converters are electronic tool that receive one type of signal and output another type of signal. There are several types of signal converters like Analog-to-digital converters, digital-to-analog converters, Frequency converters, Voltage converters, Frequency-to-voltage converters, Voltage-to-frequency converters. Signal converters convert signals from sensors into signals for industrial use and convert input analog signals into output analog signals.

The common features of signal converters are filtering and amplification. Integral filters permit some signal frequencies to pass as attenuating others. Integral amplifiers increase signals to the corresponding scale of the input device. Signal converters that contain multiplexers can unite a number of AC or DC inputs serially into one output. Signal isolation can be realized through optical isolation, magnetic induction, or the use of capacitors. Sometimes Signal converters comprise current-to-voltage converters, which create output signal voltages that are a role of the input current, and current loop converters that convert an analog or digital signal to a current loop output.

A video multiplexer is a device that helps us to put video recording of signals from various security cameras on one cassette. It handles several video signals at the same time. Video multiplexers can split a monitor into various display areas which will combine output signals from several cameras to a single monitor. The main features that used in video multiplexer are the time and date stamp that allow us to know when any recorded activity took place. An alarm output and Motion detection.

The ability of video multiplexer can be used with our computer software. It can be use with either color or black-and-white cameras. There are different Types of Video Multiplexers are available like Simplex, Duplex and Triplex. Video multiplexers are used in many closed circuit television and video observation applications. Video multiplexers take several camera signals and combine them onto one channel so we can record them on a recording system of our choice.