Non-linearity Correction Filter - FPGA MACRO

• AM/AM and AM/PM distortion curve inversion.
• Standard processor bus interface supports programmable features.

Block Diagram

The figure shows the block diagram for pre-distortion filter functions.

Description

The Pre-distortion macro implements non-linearity correction filter to reduce amplitude distortion (AM/AM) and phase modulation distortion (AM/PM).

Inverse transform look up table is core of system; table can be configured to have a single sample delay or double sample delay depending (A’ = C_nX_n+ C_n-1X_n-1).

Standard parallel bus interface provides to implement coefficients loading.

The following table lists the typical device utilization for filter functions.

Echo Canceller - FPGA MACRO

Features

• Echo cancelling technique independent from source signal type.
• Programmable echo cancelling window partition.
• Standard processor bus interface supports programmable features.

The echo canceller macro-function allows the system designer to reduce noise introduced from coupled transmission in a iso-frequency re-generator system.

For every component I/Q, the macro-function implements a FIR filter with variable taps coefficients, to compensate introduced noise.

Echo canceller filter coefficients evaluation is based on temporal correlation technique.

Echo canceller filter taps numbers and working frequency determinate echo canceller window width.

The echo canceller macro-function allows to reduce echo noise generated from coupling local transmission antenna, or from far transmission system; echo canceller window can be divided in two part, one centred on small delay, to reduce local transmission coupling noise, and the other centred on programmable delay to reduce a far coupling transmission. This technique allows to have a large echo correction window and a lower design resource utilization.

The echo canceller macro-function implements a micro-processor interface to change programmable parameter.

typical parameter example for echo canceller functions