Title :
An adaptive pre-distorter for the compensation of HPA nonlinearity
Author :
Han, Dong-Seog ; Hwang, Taewon
Author_Institution :
Sch. of Electron. & Electr. Eng., Kyungpook Nat. Univ., Taegu, South Korea
fDate :
6/1/2000 12:00:00 AM
Abstract :
A high power amplifier (HPA) is used for the amplification of transmitting communication signals. However, it produces distortions by creating AM/AM and AM/PM modulations in the transmitting signal, Accordingly, this nonlinearity results in bandwidth expansion and nonlinear distortion in the in-band signal. This paper proposes an algorithm for the operation of a pre-distorter, which is composed of a look-up table (LUT), that can compensate for the distortion produced by an HPA. For the fast initialization of the LUT, an estimation algorithm is also proposed for the HPA characteristics. Furthermore, an adaptive algorithm based on the minimization of the mean square error is proposed to compensate for the time-varying property of an HPA. The performance of the proposed algorithm is analyzed by applying the algorithm to an 8-level vestigial sideband (VSB) modulation to be used in the ATSC terrestrial digital TV system
Keywords :
adaptive estimation; compensation; digital television; least mean squares methods; nonlinear distortion; power amplifiers; radiofrequency amplifiers; table lookup; television transmitters; 8-level vestigial sideband modulation; AM/AM modulation; AM/PM modulation; ATSC terrestrial digital TV system; HPA nonlinearity; VSB; adaptive pre-distorter; amplification; bandwidth expansion; compensation; distortions; high power amplifier; in-band signal; initialization; look-up table; mean square error minimization; nonlinear distortion; performance; time-varying property; Adaptive algorithm; Algorithm design and analysis; Bandwidth; Digital modulation; High power amplifiers; Mean square error methods; Minimization methods; Nonlinear distortion; Performance analysis; Table lookup;
Journal_Title :
Broadcasting, IEEE Transactions on
