Frequency Division Duplexing. A transmission method that separates the transmitting and receiving channels with a guard band (some amount of spectrum that acts as a buffer or insulator). Allows two-way data transmission by, in effect, opening two distinct radio links. Contrast with Time Division Duplexing (see TDD). Return
Frequency Division Duplex. A duplexing technique which uses two separate channels on the same time slot for downlink and uplink transmission. FDD is suitable for full duplex voice conversation. FDD is mostly deployed in licensed spectrum due to the requirement for the availability of a pair of channels for transmitting and receiving. Compare with TDD.
Frequency Division Duplex - System of wireless communication where the data uplink and downlink are at different frequencies. Alongside TDD, this is a central transmission technology for 3G. gateway Internet server that operates as a gateway between a mobile network and the wider Internet. In addition to collecting information, a wireless gateway will also ensure that content is formatted correctly for the specific mobile device and access technology (such as WAP).
Frequency Division Duplex. In a FDD system simultaneous transmission and reception of radio signal is possible. This allows the mobile phone user to talk and listen at the time. The mode of communication is facilitated by having a frequency channel with two separate operating frequencies, one for transmission and the other for reception.
A full-duplex technique that it is used when there is a significant contiguous spectrum allocated and when synchronization between the base stations is not possible. Each direction (incoming and outgoing) occupies a different portion of the frequency band, and a rather large portion of the spectrum is consumed.
Floppy Disk Drive - Sometimes used (incorrectly) to refer to the individual diskettes used in FDDs. These days diskettes are 3.5 inches in diameter and contain 1.44MB of data. In times past, these diskettes were 5.25 inches and even 8 inches in diameter. They are known as "floppies", as they are made from polyester covered with a magnetic oxide coating and hence are flexible, although they are encased in a fairly stiff, plastic case.
Floppy Disk Drive. The transportable media recorder/player fitted as standard on the original and current PCs. Less use is being made now of the good old floppy, since the introduction of other higher capacity media types, such as Zip disks, CDs and DVDs, but it is still essential for moving small files around and for loading rescue files in a crippled PC.
Facility for the developmentally disabled. A type of nursing home primarily for developmentally disabled persons. State centers for developmentally disabled persons are FDDs. Licensed under ch. HFS 134 Adm. Codes.