User's Manual

SPEEDLAN 9000 Series Installation and Operation User Guide
Glossary-16
Sidelobe
These are 20 dB lower than the main lobe, and it is critical from a performance standpoint that antennas are aligned with
respect to the main lobe. Failure to do so may cause the radio to be interfered with or the radio may interfere with other
systems.
Signal level
This is the value of the signal level at the receiving end of the transmission path.
Simple Network Management Protocol (SNMP)
The standard protocol for TCP/IP network management that has the most common worldwide use.
Site ID (Unique)
This is the alphanumeric site address given to the terminal by you (the user).
Spread Spectrum Technology (SST)
A method of encoding (with a PN code) a digital signal in a transmitter so as to spread it over a wide range of frequencies
so that the average signal power is close to the noise floor. The same code is known to the receiver and is used to decode
the signal. Keeping the code secret provides communications security.
Submask
This term allows you to mask section(s) (depending on the class specified) of the octets in the network address. Each octet
used in the subnet mask is assigned to a data link. The leftover octet(s) are assigned to the remaining nodes.
Subnet
This term allows you to create multiple networks within one Class A, B, or C network. Each data link (octet) contains its
own unique identifier also known as the subnet. Also, each node on the same data link must belong on the same subnet
as well.
Symbol Threshold
After a signal has been acquired, the acquisition algorithm in the spread-spectrum chip continues to run a cross-correla-
tion between the expected PN sequence and the received signal, but now uses the Symbol Threshold for comparison. If
the result of the cross-correlation drops below the Symbol Threshold, the signal is considered to have been lost, and the
algorithm begins trying to acquire the signal again.