Actually,
at the time of the communication process, only 40% of mobile users said
that time and during the rest of the time is not very useful
information. All
information is transmitted to the network, it's just a waste of system
resources, but also a system that does not include more involvement. When
the transmission of radio signals transmitted voice signal is forbidden
to tackle this problem, DTX technique, GSM is used in the process. This is to reduce the level of interference and increase system capacity. In addition, this approach will also save battery mobile station and the mobile station can prolong the standby time. DTX function is not used for the data transfer will be.
GSM system, two transmission modes: a common source. In this case, the noise transmission of sound quality Pickup: There is a discontinuous transmission mode. In this case, the mobile station transmit only voice signals. Receiving end are artificial noise.
Artificial noise communication connection is fine when you do not speak the client that is used to notify listeners. And uncomfortable to hear is noise that has been designed as a comfortable noise.
Casual noise transmission measurement system that meets the requirements. DTX mode, only 260bit code is transmitted every 480ms, normal mode, 260bit code is transmitted every 20ms while. DTX mode, 260 bits SID (silence descriptor) frames will create. Frame, such as frame size, interleaving, will be processed by channel coding, and modulation then encrypted, and sent to 8 continuous spraying. At other times, no message.
DTX mode is optional. However, the standard transmission will reduce a bit the DTX mode. Especially when the two ends of the mobile communication subscribers, will influence the transmission quality will be more severe as the DTX will be used twice on the same path. In addition, to implement the DTX function, the system should be able to indicate when to start the discontinuous transmission and when it stopped, and when the active DTX coder should be able detect whether the signal is a voice signal or noise signal. Therefore, the use of VAD technique. The VAD algorithm determines the output frame is all voice or background noise by comparing the measured signal energy to the threshold defined for it. The principle is the decision that should be the noise energy is always lower than the energy of voice.
GSM system, two transmission modes: a common source. In this case, the noise transmission of sound quality Pickup: There is a discontinuous transmission mode. In this case, the mobile station transmit only voice signals. Receiving end are artificial noise.
Artificial noise communication connection is fine when you do not speak the client that is used to notify listeners. And uncomfortable to hear is noise that has been designed as a comfortable noise.
Casual noise transmission measurement system that meets the requirements. DTX mode, only 260bit code is transmitted every 480ms, normal mode, 260bit code is transmitted every 20ms while. DTX mode, 260 bits SID (silence descriptor) frames will create. Frame, such as frame size, interleaving, will be processed by channel coding, and modulation then encrypted, and sent to 8 continuous spraying. At other times, no message.
DTX mode is optional. However, the standard transmission will reduce a bit the DTX mode. Especially when the two ends of the mobile communication subscribers, will influence the transmission quality will be more severe as the DTX will be used twice on the same path. In addition, to implement the DTX function, the system should be able to indicate when to start the discontinuous transmission and when it stopped, and when the active DTX coder should be able detect whether the signal is a voice signal or noise signal. Therefore, the use of VAD technique. The VAD algorithm determines the output frame is all voice or background noise by comparing the measured signal energy to the threshold defined for it. The principle is the decision that should be the noise energy is always lower than the energy of voice.
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