Predistortion equalizer with resistive combiners and dividers

Claim 1

A predistortion equalizer for signal to be predistorted comprising: a signal processing first channel including an input terminal and an output terminal, and including first signal attenuation means coupled to said input terminal of said first channel for attenuating signals applied thereto for producing attenuated first channel signals, and first signal translation means coupled to said first attenuation means and to said output terminal of said first channel for translating said attenuated first channel signals for generating first channel output signals at said output terminal of said first channel, which first channel output signals have amplitudes which are substantially linearly related to the amplitudes of the signals applied to said input terminal of said first channel, said first channel having a reference phase for signals of a particular frequency passing therethrough; a signal processing second channel including an input terminal and an output terminal, and including second signal translation means coupled to said input terminal of said second channel for translating signals applied thereto for producing translated second channel signals, and second signal attenuation means coupled to said second signal translating means and to said output terminal of said second channel for attenuating said translated second channel signals and for generating second channel output signals at said output terminal of said second channel, which second channel output signals have amplitudes which are less linearly related to the amplitudes of the signals applied to said input terminal of said second channel than the linearity of the relationship of said input and output signals of said first channel, said second channel having a phase ranging from 90° to 270° relative to said reference phase for signals of said particular frequency passing therethrough; resistive signal dividing means including an input port adapted to be coupled to a source of said signal to be predistorted and also including first and second output terminals, said first output terminal being coupled to said input terminal of said first channel and said second output terminal being coupled to said input terminal of said second channel, for dividing the power of said signal to be predistorted into a first portion for said first channel and a second portion for said second channel, said first and second portions being of substantially equal phase; and resistive signal combining means including first and second input terminals coupled to said output terminals of said first and second channels, respectively, and also including an output port adapted to be coupled to amplifying means operating at a level tending to cause distortion, for combining said first and second channel output signals for generating a predistorted signal at said output port of said resistive combining means, which predistorted signal is the difference between said first and second channel output signals, for tending to compensate for said distortion of said amplifying means.

Claim 14

A method for producing predistorted signals, comprising the steps, over a frequency of interest, of: resistively dividing into first and second portions the signals to be predistorted; passing said first portion of said signals through a first channel having reference phase shift and also having reference magnitude, to produce first channel output signals; passing said second portion of said signals through a second channel having phase shift equal to said reference phase plus a further phase shift having a value in the range of 90° to 270° and also having magnitude which is nonlinearly related to the magnitude of said second portion of said signals to be predistorted, to produce second channel output signals; and resistively combining said first and second channel output signals for generating said predistorted signals.

Claim 15

A method for producing predistorted signals, comprising the steps, over a frequency of interest, of: resistively dividing into first and second portions the signals to be predistorted; passing said first portion of said signals through a first channel having reference phase shift and also having reference magnitude, to produce first channel output signals; passing said second portion of said signals through a second channel having phase shift equal to said reference phase plus a further phase shift having a value in the range of 90° to 270° and also having magnitude which is nonlinearly related to the magnitude of said second portion of said signals to be predistorted, to produce second channel output signals; and resistively combining said first and second channel output signals for generating said predistorted signals.