Circuit power management (option) – Comtech EF Data MIDAS 4 System and Design User Manual
Page 51
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System and Design Manual, Revision 2
Theory of Operation 3–9
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Circuit power management is provided as an option. It includes:
• Circuits at setup.
• Site level call blocking based on available High power Amplifiers
(HPA) power.
Site Level Call
Blocking
The MIDAS Controller supports dynamic site level call blocking based on the
available HPA power. The MIDAS Controller keeps track of the HPA power
for each site. A call originating from a site is blocked if it would cause the
total transmit power for that site to exceed the recommended HPA power (less
backoff). This leads to improved system stability.
AUPC Bw
Calculation
AUPC bandwidth calculation is as follows:
1. Use the data rate as the initial number of Hz for the carrier.
2. Multiply or divide by various factors to account for other link
parameters, such as:
a. For modulation:
BPSK
No Change
QPSK
Divide by 2
8PSK
Divide by 3
16QAM
Divide by 4
b. For FEC Rate, divide by the FEC rate, such as:
FEC 1/2
Divide by 0.5
FEC 3/4
Divide by 0.75
c. Reed-Solomon, multiply by:
225/205
or
1.0976
3. Multiply by the “Allocation Factor”, (suggested is 1.4) to add some
extra room for sidebands and small frequency offsets.