Справочник Пользователя для Adtran TRC6420
TRACER 6420 System Manual
Section 2 Microwave Path Engineering Basics
612806420L1-1A
Copyright © 2005 ADTRAN, Inc.
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Table 3 lists path loss values for various path lengths for the TRACER 6420 5.8 GHz system. Values not
listed in the table can be interpolated from those listed.
listed in the table can be interpolated from those listed.
5.
RECEIVER SENSITIVITY
Receiver sensitivity is a value expressed in decibels referenced to one milliwatt (dBm) that corresponds to
the minimum amount of signal power needed at the receiver to achieve a given bit error rate (BER).
Receiver sensitivity is usually a negative number of decibels, and smaller receiver sensitivity (higher
quantity negative number) is better for a given BER. Several factors affect receiver sensitivity, including
the data bandwidth of the wireless link and the amount of additional signal degradation introduced in the
receiver electronics.
the minimum amount of signal power needed at the receiver to achieve a given bit error rate (BER).
Receiver sensitivity is usually a negative number of decibels, and smaller receiver sensitivity (higher
quantity negative number) is better for a given BER. Several factors affect receiver sensitivity, including
the data bandwidth of the wireless link and the amount of additional signal degradation introduced in the
receiver electronics.
Receiver sensitivity of the TRACER 6420 is dynamic as a function of the desired bandwidth; receiver
sensitivity improves as delivered bandwidth decreases. TRACER bandwidth is provided in the form of 8
channels available for mapping to the support modules. For T1 Modules, each channel mapped represents
a single T1 interface. For Quad Ethernet Switch Modules, each channel mapped represents 2 Mb of switch
data delivered to the module. In situations where 8-channel connectivity is not required, the delivered
bandwidth can be decreased to 4 or 2 channels, and the receiver sensitivity will be improved as follows:
sensitivity improves as delivered bandwidth decreases. TRACER bandwidth is provided in the form of 8
channels available for mapping to the support modules. For T1 Modules, each channel mapped represents
a single T1 interface. For Quad Ethernet Switch Modules, each channel mapped represents 2 Mb of switch
data delivered to the module. In situations where 8-channel connectivity is not required, the delivered
bandwidth can be decreased to 4 or 2 channels, and the receiver sensitivity will be improved as follows:
Table 3. Path Loss for Given Path Lengths
Path Length
(miles)
Path Loss
(dB)
1
112
2
118
3
121
4
124
5
126
10
132
15
135
20
138
25
140
30
141
35
143
Table 4. Receiver Sensitivity for the TRACER 6420
Delivered
Bandwidth
Receiver
Sensitivity
8 Channels
-87 dBm
4 Channels
-90 dBm
2 Channels
-93 dBm
Should an interferer be present nearby, three software selectable band plans are provided
for frequency agility. Changing the TRACER 6420 band plan does not require additional
components, or opening of the radio. See > RF Link Configuration > RF Band Plan on
page 53 for additional details.
for frequency agility. Changing the TRACER 6420 band plan does not require additional
components, or opening of the radio. See > RF Link Configuration > RF Band Plan on
page 53 for additional details.