Starline Cable Equalizers; Example 1; Example 2 - Motorola BLE100 Installation And Operation Manual

Field-sweep the entire bandwidth of the amplifier to correct frequency response for passive
signature and roll-off.
Close the housing in accordance with the instructions in Section 5, "Installation."

STARLINE Cable Equalizers

Select the appropriate model SFE-100-* to compensate for cable attenuation versus frequency
and to obtain the proper output tilt. The BLE100 is equipped with the LDR/9/1G interstage
equalizer and flatness board that compensates for cable attenuation. Any cable or passive slope
beyond that of the LDR must be compensated for by selecting and installing the appropriate
SFE-100-* cable equalizer.
Equalizers are available in 1 dB increments from 0 dB through 22 dB. The following examples
describe how to choose the correct equalizer.

Example 1

The amplifier location includes 20 dB of cable (at 1 GHz) between its input and the preceding
amplifier. Consider cable loss only. Exclude any flat loss due to splitters or other passive
devices. The internal equalizer, model LDR/9/1G, compensates for approximately 9 dB of cable.
Subtract this cable length from the 20 dB of this example (20 – 9 = 11). The SFE-100-11 is the
proper equalizer in this case. With this equalizer installed, the BLE100 reproduces the output
tilt of the last upstream amplifier.
When selecting an equalizer, choose the next lower value if the exact value is not available or in
cases where the calculated value makes two choices possible.

Example 2

The BLE100 is used in a link following a fiber node with flat output. There is 18 dB of cable
between the node and the line extender, plus passive losses that are assumed to be flat. Which
is the proper equalizer to achieve the 10 dB of output tilt?
In this case, calculate the equalizer value by using the following method:
SLOPE eq = TILT out + SIG lo – SIG hi – SLOPE ieq
where: SLOPE eq = required SFE-100 slope
TILT out
SIG lo
SIG hi
SLOPE ieq = interstage equalizer slope (9 dB)
From various references, such as manufacturer's catalogs, you can determine that 18 dB of cable
at the operating frequency of 1003 MHz is 4 dB of loss at 54 MHz. This suggests that the
channel 2 signal input level to the line extender is 14 dB greater (18 – 4 = 14) at channel 2 than
it is at 1003 MHz. Our example assumes that the high-end frequency level into the amplifier is
+15 dBmV.
Substituting this information in equation (1) provides the following result:
10.0 dB + 29 dB – 15.0 dB – 9.0 dB = 15 dB
= required amplifier output tilt
= signal input level at channel 2
= signal input level at 1 GHz
Amplifier Setup
BLE100 Installation and Operation Manual
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