Digital analogue intercom is an intercom system for analogue environments, which connects one or more analogue environments wirelessly by means of wireless communication in order to solve the problems that currently exist in the field of communication.
Digital analogue intercoms have a rich range of interfaces and functions and are suitable for a variety of monitoring systems and communication networks. As the level of information technology in society continues to increase, the speed of information dissemination is greatly accelerated.
Digital analogue intercoms are not only able to achieve intercom communication functions, but also have great development potential and application prospects in voice communication and data acquisition, playing an increasingly important role in national and social development.
I. Communication methods
Digital analogue intercom is mainly used for communication between the intercom system and other wireless terminal equipment. Before the emergence of wireless terminal equipment, intercom communication usually uses wired communication; with the continuous development and maturity of communication technology, wireless communication has gradually become the mainstream form in recent years. Although in the field of digital intercom has not yet appeared wireless communication technology standards, but after years of development has formed a relatively complete protocol system.
At present, wired communication mainly includes voice communication, IP telephony, RF communication and so on. The audio communication is a communication method that includes call, audio return, audio monitoring, audio acquisition, voice output and many other functions! In addition, in the digital narrative can also achieve voice calls, data interaction, voice chime, digital intercom and digital recording and other operations.
Ⅱ.Transmission medium
The transmission medium of digital analogue intercom is analogue signal. Digital analogue intercom signal transmission speed than the analogue circuit is more than 20% faster, the bandwidth is 1-3 times greater. The digital technology used in the analogue intercom is the digital signal processed through the analogue circuit, the digital transmission method can be used TCP/IP protocol, while the digital transmission method after processing through the analogue circuit has a variety of communication modes available: UDP, BT, MU-MIMO, FSK, FDMA, etc.
Ⅲ.Transmission distance
The transmission distance refers to the distance of the sound waves emitted by the wireless intercom when the transmitting power is at its maximum under normal working conditions. In general, the wireless intercom in 1-3 transmit power point per meter for wireless communication, to use not less than 10 kHz (Hz = 1 Hz) of the wireless frequency band for wireless communication, requires the transmit power is not more than 20 kHz (Hz = 1 Hz).
The wireless communication distance has a certain influence on the transmission distance. In a good signal environment, the signal can be transmitted 20-40 metres; while in a poor signal environment the transmission distance is reduced or even impossible, and in a poor signal environment the communication distance cannot be guaranteed.
Therefore need to choose according to the actual situation suitable for wireless communication distance within the transmission signal situation, choose the transmission distance suitable for digital analog intercom system transmission application.
Ⅳ. Environmental adaptability issues
As the analog data intercom channel is two-way, can not be based on different users in different environments using digital intercom.
The general requirements of the communication network in the outdoor environment to have a high anti-interference ability; in the indoor environment to have a high anti-interference ability; indoor environment and outdoor environment there is a big difference.
In order to address these issues, due consideration should be given to the capabilities (including channel quality, frequency matching, signal strength, etc.) and the communication bandwidth required to communicate between outdoor and indoor environments. Manufacturers of analogue equipment must therefore consider their environmental suitability in order to adapt them to the various environments in which they communicate.
V. Requirements for security and control functions
In analogue systems, there are many means of network communication used. In order to ensure the security and functional integrity of the system, well-designed signal integrity protection software and procedures are required to ensure user information security. In analogue systems, strict protection of terminals is necessary.
In a digital video environment, intelligent control must be used between the intercom and the user. To ensure that video surveillance and fire-fighting equipment can work smoothly, the intercom should have a very high degree of flexibility and security.
Digital intercoms also have some special settings and functions to meet the requirements of use. It is necessary to have a detailed and comprehensive set of performance requirements for analogue intercoms as well as some safety measures to ensure this.