AIMA-FT5S
Product User Manual
Pacific Broadband Networks
18 July 2014
Page 33 of 62
QAM RF equivalent power = (Nd) x 10
–(back off /10)
Example
RF load consisting of a mix of analog and of QAM RF channels.
Analog channels = 50
QAM64 channels = 13 channels have -10 dB backoff
QAM256 channels = 15 channels have a -6 dB backoff
+
First, the total RF power of the suggested channel load must be determined. This will require the QAM
RF channels to be converted to the equivalent analog RF power. QAM RF channels operate -6 dB and
-10 dB below the analog RF channels, the RF power of QAM channels is significantly lower than the
RF power compared with analog channels.
General Rule:
10 channels of QAM64 operating at -10 dB converted to analog channels equals the same RF
power of a single analog RF channel
Formula for calculating the QAM RF to equivalent analog RF power.
(Nd) = Number of QAM RF channels
Backoff = RF delta between Analog RF and QAM RF
Typically, QAM64 operates at 10 dB below analog RF levels; QAM256 operates 6 dB below analog
RF levels.
Calculating the total RF power
13 QAM64 channels at -10 dB
QAM RF equivalent power = (Nd) x 10
– (backoff /10)
QAM RF equivalent power = (13) x 10
– (10 /10)
QAM RF equivalent power = (13) x 0.1
QAM RF equivalent power = 1.3 x analog channel
15 QAM256 channels at -6 dB
QAM RF equivalent power = (Nd) x 10
– (backoff /10)
QAM RF equivalent power = (15) x 10
– (6 /10)
QAM RF equivalent power = (15) x 0.25
QAM RF equivalent power = 3.8 x analog channel