User's Manual

SPEEDLAN 9200 User Guide Part # 34357-MNL Rev.03
Glossary-7
Fade Margin
The difference between the receiver signal input level and the receiver sensitivity. Fade margin is usually
considered the safety factor allowing the system to remain operating under additional forms of attenuation.
Fading
The loss of signal strength due to changes in the atmosphere.
Federal Communications Commission (FCC)
Government organization appointed by the U.S. President that regulates interstate communications (by use of
licenses, standards, rates, etc.).
Firewall
A firewall protects resources in a private network from the users on outside networks. It can also restrict
unwanted traffic from the private network to the outside. The firewall determines based on a set of rules
whether packets should be forwarded to their destination.
Firmware
Alterable programs in semitransparent storage (e.g., some type of read-only or flash reprogrammable
memory).
Forward Error Correction (FEC)
The ability of a receiving station to correct a transmission error. The transmitter sends redundant information
along with the original bits and the receiver uses this information to find and correct errors. This can increase
the throughput of a data link operation.
Framing
Dividing data for transmission into groups of bits, and adding a header and a check sequence to form a
frame.
Frequency
The number of complete cycles per second existing in a waveform. Note that frequency is measured in Hertz
(Hz).
Frequency Hopping (FH)
A type of spreading technique using a PN code to change the signal’s frequency between several
pre-assigned values (hopping). Although the signal itself looks like a narrow band signal at any given point in
time, it acts like a spread signal because of the frequency hopping.