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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.