Four quadrant linearizer
View Patent ↗A system includes a laser generator, and a signal distortion generator circuit inline with the laser generator modulation signal and configured to generate distortion vectors in any of four distortion vector quadrants.
1. A circuit comprising:
a signal distortion generator circuit configured to generate distortion vectors in any of four distortion vector quadrants, the distortion generator comprising:
an RF splitter adapted to split an RF input signal into positive and negative outputs;
a first diode current shunt between the positive output of the RF splitter and ground;
a second diode current shunt between the negative output of the RF splitter and ground;
a first varactor current Shunt between the positive output of the RF splitter and ground; and
a second varactor current shunt between the negative output of the RF splitter and ground;
wherein the first diode current shunt is configured to produce a positive real component of an RF predistortion signal, the second diode current shunt is configured to produce a negative real component of an RF predistortion signal, the first varactor current shunt is configured to produce a positive imaginary component of an RF predistortion signal, and the second varactor current shunt is configured to produce a negative imaginary component of an RF predistortion signal.
2. The circuit of claim 1 , further comprising:
a positive signal amplifier coupled to the positive output of the RF splitter, and
a negative signal amplifier coupled to the negative output of the RF splitter.
3. The circuit of claim 2 , further comprising:
a first feedback circuit connecting the positive output of the RF splitter to an input of the negative signal amplifier, and a second feedback circuit connecting the negative output of the RF splitter to an input of the positive signal amplifier.
4. The circuit of claim 3 , further comprising:
a controlled signal source coupled to inject current into the first and second feedback circuits.