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Application Notes: Forward Sweep and Balance

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A forward sweep reference can also be taken at this time. Press “func” and

“6” and enter a name for your reference. Some systems may want to use this

reference for tap output responses.

NOTE: Be careful with forward fiber optic transmitters in

the headend. The test point may be aligned for the input to

the "box" or the actual input to the laser diode. This could

give a faulty reference.

TIP: The Tilt mode is simple and makes selecting EQ very

easy.

Forward Balancing and Sweeping

First, balance the signal levels at the node using your Tilt and Level modes

at the band edge frequencies. Press "Sweep" and verify all is well. Press the

right diamond key for forward sweeping.

Build your reference using the same procedures you used to build the

reference at the headend. Store a reference for each leg of the node that has

actives attached.

NOTE: It’s good to compare "apples" to "apples". Don’t

change things like in-line pads and test leads once a

reference has been stored. Store a new reference

otherwise.

Proceed to the next active in line. Use a directional test point on the active

for forward balancing and sweeping. Most forward balancing is based on

unity gain at the output. If the design slope is different than the node design

slope, use tilt compensation (Sweep; Tilt; Tilt On/Off).

TIP: The "Tilt Compensation" mode of the field unit makes

it easy to get a true peak-to-valley no matter what the tilt of

the reference. The highest tilt channel programmed in your

channel plan is the most affected point, and the lower tilt

channel would be the pivot point. If no tilt channels have

been enabled, tilt compensation won’t work.

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Wavetek 147 Dokumentacja Strona 336