|
LTR Standard
Within radio technology, LTR (Logic Trunked Radio) Standard systems have no dedicated control channel. All control data is sent as subaudible data along with voice transmissions. Systems can have any number of channels from 1 through a maximum of 20. Each channel in the system is assigned a unique number (01 through 20) and these need not be sequentially assigned. Each subscriber radio must be programmed with all channels in the system in proper logical channel order (the same requirement as EDACS systems). LTR Standard Talkgroups are written in the format A-HH-GGG. * "A" is the area code and is either 0 or 1. The area code is the same for all Talkgroups in a given system and is arbitrarily chosen by the system operator; the most common use is to simply distinguish between Talkgroups on multiple systems. * "HH" is the home repeater number and has twenty possible values, 01 through 20. Talkgroups usually use their home repeater by default, unless the repeater is already in use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by another antenna connected to a radio receiver. Radio is very widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing, and other applications. In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking, and satellite communication, among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter. In radar, used to locate and track objects like aircraft, ships, spacecraf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Control Channel
In radio communication, a control channel is a central channel that controls other constituent radios by handling data streams. It is most often used in the context of a trunked radio system, where the control channel sends various data which coordinates users in talkgroups. In GSM networks, Control Channels are divided into three categories: Broadcast Channel (BCH), Common Control Channel (CCCH), and Dedicated Control Channel (DCCH).{{Cite book, title=GSM Switching, Services and Protocols, Second Edition, last=Eberspächer, first=Jörg, publisher=John Wiley & Sons Ltd, year=2001 Broadcast Channel (BCH) The group of Broadcast Channel is subdivided into three channels: # Broadcast Control Channel (BCCH) # Frequency Correction Channel (FCCH) # Synchronization Channel (SCH) The BCCH is transmitted by the base transceiver station (BTS) at all times. The radio frequency (RF) carrier used to transmit the BCCH is referred to as the BCCH carrier. The mobile station (MS) monitors the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EDACS
The Enhanced Digital Access Communication System (EDACS) is a radio communications protocol and product family invented in the General Electric Corporation in the mid 1980s. History A young designer, Jeff Childress, created an autonomous radio base-station controller, known as the GETC (General Electric Trunking Card). The GETC was a general-purpose controller with input/output optimized for radio system applications. Childress and the team demonstrated that a smart controller could be adapted to a variety of applications, but his interest was really in fault tolerance. The competition dealt with fault tolerance by means of the "brute force and ignorance" approach, deploying double the hardware for their controllers, and interconnecting them with massive and problematic relay banks . The EDACS system architecture supported large communications footprints. By making the GETC's "trunk" among themselves, one GETC per channel, the system was designed to be inherently fault-t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Repeater
In telecommunications, a repeater is an electronic device that receives a signal and retransmits it. Repeaters are used to extend transmissions so that the signal can cover longer distances or be received on the other side of an obstruction. Some types of repeaters broadcast an identical signal, but alter its method of transmission, for example, on another frequency or baud rate. There are several different types of repeaters; a telephone repeater is an amplifier in a telephone line, an optical repeater is an optoelectronic circuit that amplifies the light beam in an optical fiber cable; and a radio repeater is a radio receiver and transmitter that retransmits a radio signal. A broadcast relay station is a repeater used in broadcast radio and television. Overview When an information-bearing signal passes through a communication channel, it is progressively degraded due to loss of power. For example, when a telephone call passes through a wire telephone line, some of the powe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Controller (control Theory)
Control theory is a field of mathematics that deals with the control of dynamical systems in engineered processes and machines. The objective is to develop a model or algorithm governing the application of system inputs to drive the system to a desired state, while minimizing any ''delay'', ''overshoot'', or ''steady-state error'' and ensuring a level of control stability; often with the aim to achieve a degree of optimality. To do this, a controller with the requisite corrective behavior is required. This controller monitors the controlled process variable (PV), and compares it with the reference or set point (SP). The difference between actual and desired value of the process variable, called the ''error'' signal, or SP-PV error, is applied as feedback to generate a control action to bring the controlled process variable to the same value as the set point. Other aspects which are also studied are controllability and observability. Control theory is used in control system eng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
