User's Manual

PINEAPPLE TECHNOLOGY, INC V.6 - ADAPTIVE PRE-CORRECTOR WEB SERVICE OPERATION

DXDPRO-10VH MODULATOR MANUAL

THE INFORMATION PROVIDED HEREIN IS PINEAPPLE TECHNOLOGY INCORPORATED PROPRIETARY INFORMATION AND

CANNOT BE COPIED OR DISTRIBUTED WITHOUT PRIOR AUTHORIZATION

V.6 ADAPTIVE PRE-CORRECTOR WEB SERVICE OPERATION (Continued)

D. ECHO CANCELLING AND ADAPTIVE PRE-CORRCTION

NOTE: THIS FEATURE IS NOT INCLUDED IN THE DXDPRO LINE PRODUCTS.

THIS IS AVAILABLE AND THE CUSTOMER SHOULD REQUEST A QUOTATION

FOR PRICE AND AVAILABILITY.

The adaptive pre-corrector option works very well in combination with the echo canceller option PT2791 by

ISO-channel repeater mode with the PT2090 digital repeater unit from Pineapple Technology Inc. However,

the echo canceller‘s ability to work effectively with high positive loop gains is dependent on already

completed linearization of the amplifier non-linearity by the adaptive pre-corrector system. Therefore, when

setting in operation a system that involves the adaptive pre-corrector as well as the echo canceller in an ISO-

channel scenario it is recommended to follow one of the following two methods:

Off-Line Linearization

The ISO-channel repeater should initially be put in operation in a configuration where feedback

between output and input is non-existent. This can be done either by feeding:

a) The input with the actual RF feed off-air while feeding the power output from the ISO-repeater

into a dummy load instead of feeding it to the transmitting antenna; or,

b) A locally generated RF feed into the unit from a test transmitter which is not affected by the

output of the ISO-channel repeater.

In this configuration the adaptive non-linear pre-corrector should be run until a shoulder performance of

about 40dB or better is obtained from the power amplifier. After this initial linearization of the power

amplifier, the ISO-repeater can be put in operation with ‗live‘ input and output.

Gradual Loop Gain Ramp-Up

The ISO-channel repeater may alternatively be put in operation by starting at a low ‗max loop gain‘

setting for the echo canceller (for example 0dB or lower) and for each step allowing the adaptive non-

linear pre-corrector to maximize the power amplifier performance to a shoulder level of about 40dB or

better before increasing the permitted loop gain by a few dB.