CommScope Node AM4, Руководство пользователя

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4. Functional Description
MF0121ACP _uc.docx Manual for Node AM4 Page 35
4.2.2. Frequency Hopping
The Node AM repeater supports base band hopping (BBH) and synthesized frequency
hopping (SFH) in GSM networks.
For base band hopping (BBH) even channelized digital filters may be used. For
synthesized frequency hopping (SFH) band selective filters are needed.
4.2.3. Filter Types
Please observe that the selectivity of the filter types is not yet available with the current
software version. At the moment only the filter type “
Normal
” will be active even if another
filter is selected. From which software release onwards the selectivity described in the
following will be implemented in future is not defined, yet.
In future, there will be different filter types available for each sub-band. These filter types
are:

Normal
(good selectivity and group delay)

Wide
(low selectivity and low group delay)

Narrow
(high selectivity and high group delay)

Auto
(preferred mode)
It is advisable to select the “Auto” filter. In this case the repeater selects the best filter
type (normal, wide or narrow) automatically. The choice of filter type depends on the input
signal strength and position of the adjacent channel signals.
If narrow, strong adjacent cannel signals are received, the “
Narrow
” filter is selected. If
the adjacent channels are far from the desired band/channel, the “Wide” filter type is used.
For all other configurations, the “
Normal
” filter is selected.
4.2.4. Status Information
The
Status and Reports
menu, which is accessible via the home page of the web
interface, provides information about the current gain, output level and receive signal
strength indication (RSSI) values.
The RSSI provides controlling and monitoring of the receive level of a Base Station (DL
RSSI) or user equipment (UL RSSI) to a Node AM. It measures the level of the input
signal by detecting the RF and converting the analogue level into a digital value. The data
are processed and evaluated by software. A corresponding measurement is also made
for the output levels.
RSSI measurements are done for each band segment; for further details please refer to
the Node AM/ Node AM SW manual.