Narrow-Band Version
Application
Equipment in the narrow-band version can be operated on VF links and over CF
and radio relay routes. Security against impulse noise and disturbance voltages
is a little lower than with the broadband version.
Frequency space
The desired frequencies are closer together in this equipment version. As a
result up to 3 of the 4 possible channels (channel 1, 2, 3) can be operated
simultaneously within an ITU-T voice band of 3.1-kHz bandwidth (0.3 kHz to
3.4 kHz).
Multi-purpose
The use with PLC transmission is possible in multi-purpose operation. However,
a smaller range (transmit level distribution for all services) and less security
against interference must be expected compared with the broadband version.
Alternate multi-purpose
The use with PLC transmission is not possible in alternate multi-purpose opera-
tion.
Channel 4
Channel 4 can be used within a 4-kHz frequency space.
The position of channel 4 in the VF frequency band is defined for the following
operations:
•
Operation in the upper half of the transmission bands 2.67 kHz to 3.7 kHz
(voice band limitation 2.4 kHz with pilot 2.58 kHz)
•
Operation in the upper half of the transmission bands 2.1 kHz to 3.6 kHz
(voice band limitation 2.0 kHz with pilot 3.78 kHz)
In the second case, another four 50-Bd WT channels can be accommodated
between the voice band and the channel 4.
Applications for Narrow-Band Devices
4-Wire connection
The operation of several units in parallel at one connection is possible by using Narrow-Band (NB) devices.
2.4.3
2.4.4
Functional Description
2.4 Equipment Versions
Smart Communication, SWT 3000 Teleprotection, Equipment Manual
41
C53000-G6040-C605-1, Edition 03.2020
