Tait TB8100, Руководство пользователя

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232 Glossary
© Tait Electronics Limited December 2007
S
SAW filter
Surface Acoustic Wave filter. A band pass filter that can be used
to filter both RF and IF frequencies. A SAW filter uses the
piezoelectric effect to turn the input signal into vibrations that are
turned back into electrical signals in the desired frequency range.
selectivity
The ability of a radio receiver to select the wanted signal and
reject unwanted signals on adjacent channels (expressed as a
ratio).
sensitivity
The sensitivity of a radio receiver is the minimum input signal
strength required to provide a useable signal.
SINAD
SINAD (Signal plus Noise and Distortion) is a measure of signal
quality. It is the ratio of ( noise + distortion) to (noise +
distortion). A SINAD of 12 dB corresponds to a signal to noise
ratio of 4:1. The TB8100 can provide an approximate SINAD
value while in service by comparing the in-band audio against
out-of-band noise. This value should not be relied upon to make
calibrated measurements.
Sleep mode
Sleep mode is a power saving state in which a part of the base
station is switched off, and then periodically switched on again.
Standby mode
Standby mode is a mode of base station operation in which active
service is suspended so that special operations can be carried out,
such as programming the base station with a new configuration.
status message
A status message is a set of information about the base station that
can be emailed. It identifies the base station, indicates the current
operating channel, lists the status of all alarms, and gives the
current values of a number of other monitored parameters. It also
contains the alarm log.
subaudible
signalling
Subaudible signalling is signalling that is at the bottom end of the
range of audible frequencies. The TB8100 base station supports
CTCSS and DCS subaudible signalling.
subtone
A subtone (subaudible signalling tone) is a CTCSS tone or a DCS
code.
switching range
The switching range is the range of frequencies (about 10 MHz)
that the equipment is tuned to operate on. This is a subset of the
equipment’s frequency band.