ADTRAN 12804108L1A, Системное руководство

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Section 2 Microwave Path Engineering Basics TRACER 4108/4208 System Manual
20 © 2003 ADTRAN, Inc. 612804208L1-1B
Table 3 lists path loss values for various path lengths for both 2.4 GHz and 5.8 GHz systems. Values not
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.
Receiver sensitivity of the TRACER 4108/4208 is dynamic as a function of desired bandwidth; receiver
sensitivity improves as delivered bandwidth decreases. In situations where 8xT1 connectivity is not
required, the delivered bandwidth can be decreased to either 4xT1 or 2xT1, and the receiver sensitivity will
be improved as follows:
Table 3. Path Loss for Given Path Lengths
Path Length
(miles)
Path Loss (dB)
at 2.4GHz
Path Loss (dB)
at 5.8 GHz
1 104 112
2 110 118
3 114 121
4 116 124
5 118 126
10 124 132
15 128 135
20 130 138
25 132 140
30 134 141
35 135 143
Table 4. Receiver Sensitivity for the TRACER 4108/4208
Delivered
Bandwidth
Receiver Sensitivity
Active
T1 Ports
TRACER 4108 TRACER 4208
8xT1 -90 dBm -85 dBm A – H
4xT1 -93 dBm -89 dBm A – D
2xT1 -97 dBm -92 dBm A, B
Should an interferer be present nearby, three software selectable bandplans are provided
for frequency agility. Changing the TRACER 4108/4208 bandplan does not require
additional components, or opening of the radio. See TRACER System Option > RF
Bandplan on page 47 for additional details.