Narrowband

The term narrow- band and narrow -band communication, English narrow ribbon is handled according to the context in the field of communications technology and in the area of Internet access with different meanings.

Communications Engineering

In the field of communications engineering, the term narrowband describes a communication channel whose bandwidth is so low that the magnitude frequency response can be assumed almost constant. This is equivalent to a constant in the entire band group delay. A non- linear response, as is the case with the emergence of broadband, leading to distortions in the transmission channel. In narrow- band transmissions so it is possible without channel equalization, which is based on adaptive filtering to get along.

For digital data transmission is equivalent to a specified narrow band transmission of the symbol rate. Each transmitted symbol required to transmit one symbol duration. Is the symbol duration is longer than the transmission time of the transmission channel is a narrow band communication steps:

It is essential that the setting of a narrow -band transmission is not fixed to concrete numerical values ​​of a certain range, but on the respective edge conditions such as the physical parameters of a radio link, oriented.

Internet access

The term is narrow band for narrowband networks or narrowband accesses used, which are characterized by a bandwidth of less than or equal to 3.4 kHz or a bit rate of less than 64 kbit / s in the field of telephone networks and with the advent of Internet access from the 1990s. This rigid definition is based in part to the bandwidth of the analog landline telephony from 300 Hz to 3.4 kHz, on the other hand corresponds to the bit rate of 64 kbit / s ISDN bit rate of a so-called B- channel. In the ITU -T Recommendation I.113, the term is fixed narrowband service with a bit rate of a base channel of less than or equal to 64 kbit / s.

At the region of the narrow -band networks for Internet access so include not only the telephone system and telephone modems, and ISDN and mobile networks such as GSM with GPRS. Internet access such as DSL systems are among the broadband Internet access.