An automatic phase adjustment scheme for RF and Cartesian feedback linearizers

Author

Faulkner, Michael

Author_Institution

Sch. of Commun. & Inf., Victoria Univ. of Technol., Melbourne, Vic., Australia

Volume

49

Issue

3

fYear

2000

fDate

5/1/2000 12:00:00 AM

Firstpage

956

Lastpage

964

Abstract

Amplifier linearization schemes based on modulation feedback (e.g., Cartesian feedback) require a phase correction circuit to stop instability and limit the level of the out-of-band noise floor. It is shown that the optimum phase corrector setting corresponds to the minimum output power condition of the amplifier. A new and very simple method by which the phase correction circuit is adjusted is described. The scheme uses the supply current to the final stage amplifier as a measure of the output power and minimizes this by using a simple direct search algorithm. Phase correction to within 5° of optimum can be obtained after about 50 iterations. The performance is limited by hysteresis in the supply current feedback signal

Keywords

circuit stability; electric current measurement; feedback amplifiers; linearisation techniques; noise; nonlinear network analysis; phase measurement; power amplifiers; radiofrequency amplifiers; search problems; Cartesian feedback linearizer; RF feedback linearizer; RF feedback system; RF nonlinear power amplifier; amplifier linearization; automatic phase adjustment; current measurement; direct search algorithm; instability; minimum output power condition; modulation feedback; optimum phase corrector setting; out-of-band noise floor; output power measure; performance; phase correction circuit; phase error measurement; supply current; supply current feedback signal hysteresis; system noise model; Circuit noise; Current supplies; Feedback circuits; Noise level; Phase modulation; Phase noise; Power amplifiers; Power generation; Radio frequency; Radiofrequency amplifiers;

fLanguage

English

Journal_Title

Vehicular Technology, IEEE Transactions on

Publisher

ieee

ISSN

0018-9545

Type

jour

DOI

10.1109/25.845112

Filename

845112